#480 – Dave Hone: T-Rex, Dinosaurs, Extinction, Evolution, and Jurassic Park

Dave Hone is a paleontologist, expert on dinosaurs, co-host of the Terrible Lizards podcast, and author of numerous scientific papers and books on the behavior and ecology of dinosaurs. He lectures at Queen Mary University of London on topics of Ecology, Zoology, Biology, and Evolution. Thank you for listening ❤ Check out our sponsors: https://lexfridman.com/sponsors/ep480-sc See below for timestamps, transcript, and to give feedback, submit questions, contact Lex, etc. Transcript: https://lexfridman.com/dave-hone-transcript CONTACT LEX: Feedback – give feedback to Lex: https://lexfridman.com/survey AMA – submit questions, videos or call-in: https://lexfridman.com/ama Hiring – join our team: https://lexfridman.com/hiring Other – other ways to get in touch: https://lexfridman.com/contact EPISODE LINKS: Dave’s Website: https://www.davehone.co.uk/ Dave’s Books: https://amzn.to/4pbk828 Terrible Lizards Podcast: https://terriblelizards.libsyn.com/ Dave’s Blog: https://archosaurmusings.wordpress.com/ Dave’s Academic Website: https://www.qmul.ac.uk/sbbs/staff/davidhone.html SPONSORS: To support this podcast, check out our sponsors & get discounts: Lindy: No-code AI agent builder. Go to https://go.lindy.ai/lex https://lexfridman.com/s/lindy-ep480-sc BetterHelp: Online therapy and counseling. Go to https://betterhelp.com/lex https://lexfridman.com/s/betterhelp-ep480-sc Shopify: Sell stuff online. Go to https://shopify.com/lex https://lexfridman.com/s/shopify-ep480-sc LMNT: Zero-sugar electrolyte drink mix. Go to https://drinkLMNT.com/lex https://lexfridman.com/s/lmnt-ep480-sc AG1: All-in-one daily nutrition drink. Go to https://drinkag1.com/lex https://lexfridman.com/s/ag1-ep480-sc OUTLINE: (00:00) – Introduction (00:22) – Sponsors, Comments, and Reflections (07:18) – T-Rex’s size & biomechanics (31:00) – T-Rex’s hunting strategies (44:07) – History of dinosaurs on Earth (1:04:38) – $31.8 million T-Rex fossil (1:17:44) – T-Rex’s skull and bone-crushing bite force (1:36:33) – What Jurassic Park got wrong (1:54:52) – Evolution and sexual selection (2:15:26) – Spinosaurus (2:26:02) – What Jurassic Park got right (2:33:35) – T-Rex’s intelligence (2:43:34) – Cannibalism among T-Rex (2:49:05) – Extinction of the dinosaurs (3:06:15) – Dragons (3:22:39) – Birds are dinosaurs (3:33:23) – Future of paleontology PODCAST LINKS: – Podcast Website: https://lexfridman.com/podcast – Apple Podcasts: https://apple.co/2lwqZIr – Spotify: https://spoti.fi/2nEwCF8 – RSS: https://lexfridman.com/feed/podcast/ – Podcast Playlist: https://www.youtube.com/playlist?list=PLrAXtmErZgOdP_8GztsuKi9nrraNbKKp4 – Clips Channel: https://www.youtube.com/lexclips

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Lex Fridman?

  The following is a conversation with Dave Hohn, a paleontologist, expert on dinosaurs, co-host of the Terrible Lizards podcast, and author of many scientific papers and books on the behavior and ecology of dinosaurs. This was truly a fun and fascinating conversation.

• 0:22Lex Fridman?

  And now, a quick few second mention of each sponsor. Check them out in the description or at lexfridman.com/sponsors. It's the best way to support this podcast. We got Lindy for AI agents, BetterHelp for mental health, Shopify for selling stuff online, Element for electrolytes, and AG1 for my daily multivitamin. Choose wisely, my friends. And now, onto the full ad reads. They're all here in one place. I try to make them interesting, but if you must skip, please still check out the sponsors. I enjoy their stuff. Maybe you will too. To get in touch with me, for whatever reason, go to lexfridman.com/contact. All right, let's go.

• 1:05Lex Fridman?

  This episode is brought to you by Lindy, a platform that helps you build multiple AI agents in minutes. They have their new Lindy Build tool, which basically goes from prompt to business. You type in the prompt, it generates the full stack, builds the backend database, builds the frontend, all the UI components, sets up the staging, deploys it, tests it, really thoroughly tests it, doing all the QA stuff, and then ships it. Plus, it has a large number of integration. I believe with over 1,500 tools, it is really well,

• 1:45Lex Fridman?

  which matters to me, integrated with all the Google products, Gmail, Google Drive, Docs, Calendar, and so on. Anyway, the tricky thing to get right here with the utilization of AI agents is to minimize the number of times you fall over and mess things up and so on. Lindy does a really, really good job of minimizing that even for complex workflows. Sign up at lindy.ai/lex to get two weeks free plus 50% off a pro plan for a year. That's lindy.ai/lex. This episode is also brought to you by BetterHelp, spelled H E L P, help. They figure out what

• 2:27Lex Fridman?

  you need and match you with a licensed therapist in under 48 hours. Over 350 million messages, chat, phone, video sessions, over 34,000 licensed therapists, and over 4.4 million people that got help through BetterHelp. I think about the landscape of suffering that is out there. People feeling alone, heartbroken, afraid, going through a difficult time in their life. Anything that can help alleviate that is something I'm a big supporter of. One of the big positives on that front of BetterHelp is that it's just easy to get started. And

• 3:09Lex Fridman?

  that's often the hardest thing to do, the first step. Anyway, check them out at betterhelp.com/lex and save in your first month. That's betterhelp.com/lex. This episode is also brought to you by Shopify, a platform designed for anyone to sell anywhere with a great looking online store. I set one up in minutes at lexfigment.com/store that sells a couple of shirts. I should probably add some more in there. I just have to think about some interesting designs. There's thousands of integrations and third-party apps, including one of the ones I'm using for on-demand printing of t-shirts. And as I've said many, many, many, many, many times, it's built on Ruby on Rails

• 3:51Lex Fridman?

  and was the thing that showed that Ruby on Rails is a performant beast. Not just that Ruby is a beautiful programming language, but the thing can scale and perform when latency is a crucial thing. Beauty and power, friends, can go hand in hand. You can sign up for a $1 per month trial period at Shopify.com/lex. That's all lowercase. Go to Shopify.com/lex to take your business to the next level today. This episode is also brought to you by Element, my daily zero sugar and delicious electrolyte mix. My favorite flavor is, of course, watermelon salt. I've been training more and more jiu jitsu recently, stepping back on the mat,

• 4:36Lex Fridman?

  doing some hard training sessions. Now, sometimes, you know, six, seven rounds, sometimes 10 plus rounds. And of course, I'm pretty hard drilling for the class portion. And for whatever reason, I don't usually get much water during the class. Just don't like stepping off the mat. So when I'm done with the class, I have a big, what is it? 28 ounce bottle with water and a pack of Element in it. And it's just tastes and feels so good to get water back in my system. And feel like I've earned it.

• 5:12Lex Fridman?

  Jiu jitsu really is one of the sources of happiness for me. Anyway, get a free eight count sample pack with any purchase. Try it at drink element.com/lex. This episode is also brought to you by AG1, an all in one daily drink to support better health and peak performance. It's become a bit of a tradition for me to do a long run along the river, especially if it's 10 plus miles in the Texas heat.

• 5:40Lex Fridman?

  It just feels so good to get back home, make an AG1, and then put it in the freezer for like 30 minutes. It gets really nice and cold. And then I sit back, relax, and think about life as I sip on the AG1. I don't know, those little habits, those little mini traditions that you have inside your day, especially when I'm at home. It's just a source of little happy moments. And I'm grateful for those moments, especially when there's turmoil from the outside world. It is good to find raspous, brief moments of escape in the happy habits of life.

• 6:25Lex Fridman?

  I sound a bit like Bob Ross about the human condition versus a painting. Well, here we are. Anyway, they'll give you a one month supply of fish oil when you sign up at drinkag1.com/lex. This is the Lex Fridman Podcast. To support it, please check out our sponsors in the description or at lexfridman.com/sponsors. And consider subscribing, commenting, and sharing the podcast with folks who might find it interesting. And now, dear friends, here's Dave Hohn.

• 7:18Lex Fridman?

  Let's start with the T. rex dinosaur, possibly the most iconic predator in the history of Earth. You have deeply studied and written about their evolution, biology, ecology, and behavior. So let's first maybe put ourselves in the time of the dinosaurs and imagine we're standing in front of a T. rex. What does it look like? What are the key features of the dinosaur in front of us?

• 7:40Speaker 01

  It's gigantic. It's almost trite now because everyone knows T. rex is massive. But yes, if you actually stand in front of one, you would be seriously impressed. Just how absolutely vast they are. Um. So I've got a copy of a T-Rex skull downstairs from my office. And yeah, I I could fit comfortably through its mouth. So it would be just about capable of swallowing me whole. And I'm a pretty big guy. Your body, you can fit in it to small.

• 8:07Speaker 01

  I can fit through it. Wow. And it's not even a particularly big one. It's a copy of the one that's in the Smithsonian. And they get bigger than that. You have a two scale copy. Yeah, yeah. Yeah, it's a it's a cast. It's just a giant mold made and then pull that like the dentist do your teeth, but very, very big. So, yeah, they are twelve-ish meters long. So what's that? Fourteen yards? Four and a half, maybe five to the top of the head standing up. So another six yards high and then seven-ish metric tons. What's that? About eight and a half short tons. So a colleague of mine, Tom Holtz, described them as an orca on land. But that's it. It is a killer whale sized animal.

• 8:53Speaker 01

  But on legs on land. And those are massive predators. So you're looking at something absolutely colossal. And I think that is what will stun you. I think people don't realize how big a lot of animals are, which sounds weird. But I used to work in a few zoos and something I think you notice is when you go and see things like elephants or giraffes or rhinos. Everything's built to the scale of the animal. The elephant house is huge. The doors are huge. The bars are huge. The food is huge. And so you don't see them in the context of something that you have a good frame of reference for. And I learnt this, yeah, when I was at London Zoo and

• 9:34Speaker 01

  was it going into the basement of the old Elephant and Rhino Pavilion and a rhino stuck its head out from like this gap in the wall. And the head was twice the size I thought it was. Once you stood next to it. And the same with an elephant. I once stood next to an elephant closer than you are to me now. And you go, oh, oh, they are so much bigger than I thought. And I think it's similar in museums, like even when you get up relatively close to a T-Rex skeleton. There's a bit of space between you and it and then some bars and then it's usually raised up a little bit and a mount it on a little mount to hold the platform and then you stand back from that. And you don't actually get to stand like under them. And when you do that, yeah, you realize that, yeah, the the foot finishes at my knee.

• 10:20Lex Fridman?

  So is a T. rex bigger than an elephant? That'd be fair to say?

• 10:23Speaker 01

  Yeah, I mean, a very large savannah African elephant is five to six tons. And we're looking at seven plus and a biped and a carnivore. So, yeah, you know, a a big lion, a big lion is two hundred kilos, so four hundred and thirty pounds. Yeah.

• 10:45Lex Fridman?

  Well, that's what that's why I mean, it's widely considered to be probably the most epic predator in the history of Earth.

• 10:52Speaker 01

  Yeah, I mean, and I think more than that, it's I think it's one of the most iconic animals, period. I mean, if you're if you're listing things that the average person has heard of. Lion, elephant, giraffe, tiger, hippo, rhino, there's a few more, but T. rex is coming somewhere up in that list. That's how prominent it is as an animal. So, yeah, it's it's almost inescapable as a paleontologist. And then doubly so for me, who works on dinosaurs and doubly so again, because I do work on tyrannosaurs. But, yeah, it just dominates conversations.

• 11:26Lex Fridman?

  Well, some of the other features maybe we can go through.

• 11:28Speaker 01

  Yeah.

• 11:29Lex Fridman?

  So big skull, big head, small hands.

• 11:32Speaker 01

  Massive head, very kind of boxy, it's very robust.

• 11:38Speaker 01

  Big forward facing eyes, massive eyes, massive, I mean, tennis ball sized eyes, these things had amazing eyesight.

• 11:47Speaker 01

  Yeah, giant teeth is a cast of a.

• 11:50Lex Fridman?

  What?

• 11:50Speaker 01

  Tyrannosaurus rex. Yeah, I know. So.

• 11:53Lex Fridman?

  How?

• 11:53Speaker 01

  It it it looks a bit bigger than it is. So this is all root. So this would be stuck in the jaw.

• 11:57Lex Fridman?

  Right, but that tip part is that's the tooth.

• 11:59Speaker 01

  The the tip, as you call it, and, yeah. You know, so that would comfortably go through pretty much any part of it. And then you realize just how thick it is. So this is a cast of a thing called carcarodontosaurus from Africa, you get it down in Niger and a few other places like that. And they're very, very big, not as big as T-Rex, but not a million miles away. And then if you look at the teeth in profile, they're a surprisingly similar shape and not far off in size as well. And then you look at them that way on and you realise it's a third of the width. So this isn't just massive, it's thick. And of course, being thick, it makes it strong.

• 12:41Speaker 01

  And with that giant head, with all that extra bone and then all the extra musculature attached to that giant head, they've got this uber powerful bite and the ability to just chomp through basically thing it wants to. So yeah, they are truly unusual in that regard, even actually compared to a lot of the other very big tyrannosaurs. They're often a kind of step above in their proportions.

• 13:07Lex Fridman?

  So incredible crushing power in the jaw.

• 13:09Speaker 01

  Yeah. And then, as you say, like this really short bull neck, because you've got this massive weight of this head up front. So you need to hold it up and not tip forwards. Really quite a massive body. Again, there's two or three other big carnivorous dinosaurs, which people argue, oh, maybe they're a little bigger than T-Rex. Maybe they're a little smaller, but it's always in terms of length, which is one way of looking at things. You know, pythons are very long, but they're nothing like as massive as, yeah, a lion or a tiger. Same thing, T-Rex is massive, it is built. So really big kind of barrel shaped chest, making the body very, very big as well. And so that's why, yeah, there's things like gigganotosaurus and mapusaurus in South America.

• 13:50Speaker 01

  Maybe they get a bit longer, another metre or so in length, but in mass, we're talking about maybe only two thirds, three quarters. So T-Rex is just massively bigger than basically any other big carnivore we know of.

• 14:04Speaker 01

  And then, yeah, little arms, as you say, so this is a not great, but it's a cast of a T-Rex arm. It's not the biggest animal, they do get a bit bigger than this. But as I love showing, it's not a million miles off the size of my own. And. I could do with a diet, but I don't weigh seven tons. So, yeah, it really is really pretty small.

• 14:28Lex Fridman?

  Two claws, two fingers?

• 14:30Speaker 01

  Yeah, so two fingers, some you will see sometimes that they say there's a third. This is a slight misnomer. So you do see this extra little bone here. This doesn't turn up in all of them and it's an extra hand bone. So it's these, the metacarpals, but it's not supporting an extra digit.

• 14:45Lex Fridman?

  So mostly functionality wise, it wasn't very functional.

• 14:48Speaker 01

  They're not doing very much at all. Um, you know, you've, this is what's called the deltoupectoral crest. It's really important for basically big arm movements because it's deltoids and pectorals. Um, the radius and ulna are really quite thin, thinner than ours. The fingers are pretty stocky. The claws look big and curved and they are, but other tyrannosaurs and indeed other carnivores generally much more curved claws. And then they have, um, these little things. Uh, where can I say it? So there you see there's a little mark. That's a ligamentous pit. And so what you can imagine is if you're trying to hold on to something and something's wriggling, you want grip. And there's a risk that you're just like dislocate your fingers.

• 15:32Speaker 01

  So we have ligaments that hold bone to bone. And if you just put it flat to flat surface area, there's only so much you can attach. Whereas if you turn that into a little hemispherical dip, you get a lot more surface area for your area. If that makes sense.

• 15:47Lex Fridman?

  Yeah.

• 15:48Speaker 01

  So if you have a really big ligamentous pit, it means there's a really big ligament, which means your fingers are really strong and they're really resistant to being wiggled around and pulled as if, you know, you've grabbed something that doesn't want you to kill it. Well, T. rex has probably the smallest ligamentous pits of any tyrannosaur. So that kind of suggests it's not doing very much. And again, when you look at the claws proportionally, they're not that big and they're not that curved. So even though it looks like quite a wicked thing to us, remember, put this on a seven ton animal whose individual teeth are the size of entire fingers. Suddenly that arm doesn't look like it's doing very much. What about the feet? So massive, again, not surprisingly, you're supporting a colossal amount of weight.

• 16:31Speaker 01

  But they have this beautiful adaptation in the foot. So the equivalent bones in the foot, the metatarsals, so for us make up the flat of the feet. But these animals walk like birds, they've got three toes on the ground and then the metatarsal stick nearly vertically. And that overall extends the length of the leg, so you can walk a little bit faster. You get a slightly bigger stride length. Don't worry, I've got the right bone here.

• 16:55Speaker 01

  Nice. But they also have, yeah, there's a good one, that one's a great one. But they also have this really neat adaptation in the middle bone. So you can see it on this one quite well. And this is actually not a tyrannosaur, this is an ornithomimosaur. So one of the really ostrich-like ones, Gallimimus, from the first Jurassic Park. It has the same thing, you can see the normal bones would be really quite long and square and then flat at the top. And instead, this thing shrinks in the middle and turns into this kind of flattened diamond shape. And what that means is the bones either side kind of lock it. In fact, at the top end, it actually tends to wiggle a bit. So it actually goes left and then right.

• 17:38Speaker 01

  And of course, what that really does is then help these things lock together. And so this is an adaptation to basically lock the foot and make it stable. And we see it in a whole bunch of things independently evolved. Early tyrannosaurs don't have this, early ornithomimosaurs don't have this, the over at Tyrannosaurus, the early ones don't have this, and the later ones acquire it. And a couple of other groups as well. And it's about making the foot stable. And what that really does is make the foot energy efficient. So you can imagine, as an animal, you know, we have some cartilage and we've got some ligaments and tendons joining all the bones together and holding joints stable. When you push down, that's going to compress them to a little degree. And when you lift that weight off, they're actually going to spring back. You're going to get a tiny little energy return.

• 18:22Speaker 01

  It's the idea of those air solvers they put in all the trainers and stuff in the in the nineties. It's that same principle. And you will, you'll get a little bit of energy return. But of course, big force, particularly for a big, heavy animal, it's going to take the kind of path of least resistance. And so if your bones are all kind of loose in the foot, what they're going to do is they're going to tend to splay out. And you're actually going to lose that energy. But if you lock the feet together, the bones can't move. And instead, that's going to further compress those soft tissue bits and give you a bit more spring.

• 18:57Lex Fridman?

  And this is all about, I mean, this is about the mobility, about the dynamics of the movement.

• 19:01Speaker 01

  It makes you more efficient. It means you're putting less energy into walk because you're just getting a little bit of spring off every single step.

• 19:09Lex Fridman?

  I should say that I deeply admire people like Ross Tedrick, like the boss of Dynamics teams, like the Tesla Optimus robot teams that look at bipedal and the quadrupeds robot movement.

• 19:21Speaker 01

  Yeah.

• 19:22Lex Fridman?

  And they tried to make human-like movement to, you know, basically efficient movement. And so the question here is how the hell is a T-Rex its size bipedal able to move as a predator? It's a weird body shape, is it not?

• 19:38Speaker 01

  I mean, the big head makes it look more odd, but you look at dinosaurs as a whole. And over a third, probably forty, forty-five percent is the group called theropods, which were all biped. So T-Rex, Allosaurus, Philosaraptor, Spinosaurus, many, many others that people may have heard of. They're all bipeds built in this way. There's a whole bunch of ancestral groups which are doing something very similar, including various crocodiles or relatives of crocodiles. And then the birds are bipeds. Birds are actually doing it in a much weirder way than theropods are. The theropods are basically a lizard on its back legs. I'm oversimplifying a lot. I can hear paleontologists screaming as I've just said,

• 20:20Speaker 01

  it's a lizard standing up. It's not a lizard standing up, but they're doing a lot of the same stuff in the same way. And that is really functionally about where you put muscles. Because what you really want to do to walk forwards is you want to basically pull the leg back so that you're pushing the body off. And the way they do that is the musculature on the tail. So we don't have a tail, and indeed mammals that even do have a tail, you know, elephants and even lions, you know, it's a piddly little thing. There's not a lot of muscle there. But if you look at a lizard, particularly if you look at something like a crocodile, you see this massive, massive block of muscle sitting on the first third to half of the tail. And that's what dinosaurs are doing. It's the same thing as lizards

• 21:04Speaker 01

  and crocs. They have this giant set of muscles on the first half of the tail. That's anchoring on the femur, so the thigh bone on the back of that, and muscles contract. That's the one thing they do. But now you've got a giant muscle. Yeah. And T-Rex, this, this muscle's like two and a half, three meters long. It's going to be like this wide in the middle. So when that contracts, the leg goes back, foot stationed around the ground. So the animal goes forwards.

• 21:30Lex Fridman?

  So the, the tail is.

• 21:31Speaker 01

  Integral to movement.

• 21:33Lex Fridman?

  It's, it's a huge part of the biomechanics of the movement.

• 21:35Speaker 01

  We do it with the butt. So we're kind of weirdly how we organize our muscles. But there's a, this is generally probably a better way of doing it, because you can get a really long muscle. And of course, the longer the muscle, the more contraction you can have. The hyper version of this is kangaroos. So kangaroos supposedly get more efficient the faster they move. They get so much energy return that when they're moving faster, they get more compression from the landing, meaning they get more spring.

• 22:05Lex Fridman?

  So we should be imagining this gigantic, thick tail, big body.

• 22:10Speaker 01

  Oh, yeah.

• 22:10Lex Fridman?

  Big head.

• 22:11Speaker 01

  Yep.

• 22:12Lex Fridman?

  And biped. And how fast does it move?

• 22:17Speaker 01

  So this is one of those things that's gone backwards and forwards and backwards and forwards. There was a paper arguing that we'd probably been overestimating various speeds, primarily based on footprints. There's been, I don't know how many papers trying to do T-Rex speed. The most recent one that was pretty detailed, I think, had it clocked at. So I think I think it was twenty five miles an hour, so forty K P H was the very upper end of the estimate. So probably a bit less than that.

• 22:49Lex Fridman?

  Well, that means it can move.

• 22:51Speaker 01

  Yeah, so that's the but that's the thing, like, big things move quick. I've seen Rhino and Hippo going at full tilt. And yeah, they're a lot quicker than you'd think. And at least part of it is simply stride length. When your legs are three ish meters long, it's hard not to cover a lot of ground with a single step. And yeah, big, big theropods, T-Rex is going to be a power walker. It's not going to run in the conventional biomechanical sense where both feet are off the ground at one.

• 23:23Lex Fridman?

  So it's not running as power walk.

• 23:24Speaker 01

  Yeah. But when you've got a four or five meter long stride, it doesn't really matter whether you're airborne or not.

• 23:34Lex Fridman?

  Power walker. So you're never so running, there's moments in time when both feet are off the ground. And you're saying likely here, one foot is always on the ground.

• 23:43Speaker 01

  Yeah, it pretty much has to be for loading.

• 23:45Lex Fridman?

  Oh, for just because of the mass of the thing.

• 23:47Speaker 01

  Yeah, yeah, yeah.

• 23:48Lex Fridman?

  Okay, all right.

• 23:49Speaker 01

  You know, that's the origin of cinema.

• 23:51Lex Fridman?

  What's that?

• 23:52Speaker 01

  It's whether is where this is Edward Mybridge. So the the origin of cinema was a bet as to whether or not whilst running, a horse had all four feet off the ground. And no one really knew this for sure. And a guy called Edward Mybridge, he was British, but he was living in the States. He was a keen photographer. And he basically did what people have seen the Wachowskis do for The Matrix. He set up a whole row of cameras, and set up a whole bunch of triggers, and had a horse run through them. So it took loads of photos. And lo and behold, in one of them, the feet are off the ground, the guy won his bet. But he also realized that we already had things like zoopraxiscopes, you know, the little thing you spin with a with a slit. And so you see that, right?

• 24:35Speaker 01

  So he did that with horses. And now you have a moving photograph. And that's pretty much the origin of cinema was a bet about biomechanics.

• 24:44Lex Fridman?

  Yeah, it's always a good question and a bet. And there you go. You're off to the races.

• 24:49Speaker 01

  Yeah.

• 24:50Lex Fridman?

  All right. All right. So we're standing in front of this thing.

• 24:52Speaker 01

  Yes.

• 24:53Lex Fridman?

  Uh, how screwed are we, you and I? We're back in the time of the dinosaurs. What's the probability of our survival?

• 24:59Speaker 01

  There's two big things to weigh up, which are going to be interesting, which is, would they even consider us a potential meal? Because we know that animals that have never, animals have to learn stuff. And so animals that have never encountered things before are often that they don't have a response because they don't know what their response should be.

• 25:21Lex Fridman?

  We should say during that time, there was not something that looked like primates.

• 25:24Speaker 01

  No, absolutely nothing.

• 25:26Lex Fridman?

  So we would look very weird.

• 25:27Speaker 01

  We would, we would look weird. Yeah. So, you know, there's lots of really cool records of, um, particularly you've got down in Indonesia and stuff, we've got these insane volcanic spires and at least these tiny little valleys. And people go in there and they go, yeah, the animals walk up to us. They've never seen a human. They don't know what it is. So it might look at us and animals are fundamentally cautious. It doesn't know if we're a threat. So maybe it might just find us weird or in some way, shape or form off putting. And so we may not even be considered on the menu.

• 26:08Speaker 01

  The other thing is we might be too small. My suspicion is we're not. So animals, carnivores typically take stuff that is much, much smaller than them. Despite basically every dinosaur documentary movie ever shows T. rex hunting an adult triceratops, which is like the same size as it. Uh, and every documentary, you've got to have lions taking down a wildebeest or even a buffalo. Like, these are weird and rare outcomes. These don't usually happen. The vast majority of active predation is on stuff much, much, much smaller than you. I totted some of this up for a paper I did on Microraptor, this really small gliding dinosaur from China, where we actually have a bunch of specimens with various stomach contents in them.

• 26:52Speaker 01

  And we were coming up with numbers of about like five to 20% of the mass being typical. So prey versus predator. And that's actually very similar to what we see with modern carnivores. And it's not far off what we've seen. Even with things like tyrannosaurs, where you occasionally find consumed bones from prey. So if we put the lower end of that as 5% of the mass of a T-Rex, we might actually be okay. If it doesn't consider us worth the hassle, then assuming you're encountering a big adult and not a half sized one that's maybe only weighs a ton, then we might be all right.

• 27:30Lex Fridman?

  What would be the survival strategy? So the, there's a thing that you criticized not being true that I guess in Jurassic Park, not moving.

• 27:39Speaker 01

  Yeah, it's nonsense. They can see really well. Like I said, like T-Rex has giant eyeballs. People don't realize that because like whales and like elephants, it looks small compared to the size of the animal. But what you're in really important for vision is absolute size, not proportional size. And absolutely their eyes are gigantic.

• 28:00Lex Fridman?

  Probably the biggest on earth at that time.

• 28:01Speaker 01

  Yeah, a guy called Kent Stevens did a paper. He's got a really nice graphic of it. If you, if you just put S D E V E N S T-Rex. There's the one with the, there we go. That's the one with the googly eyes. That's a baseball or a tennis ball. Sized eyeball. And when you think about the incredible visual acuity of something like an eagle, which has eyes not much bigger than ours. Think about what that's gonna do. And we absolutely know, there's been loads of studies on this in mammals and birds and other things as well that. Basically eyeball size correlates with visual acuity and that can fold in two different ways.

• 28:42Speaker 01

  It can be like general sharpness, like how well can you see a long way away? So eagles and vultures, that's really important. Or it can be good in low light.

• 28:52Lex Fridman?

  And I now discovered that there's a nature was metal subreddit.

• 28:56Speaker 01

  Yeah, yeah.

• 28:57Lex Fridman?

  Which is.

• 28:57Speaker 01

  Gnarly, gnarly paleo things.

• 28:59Lex Fridman?

  Yeah.

• 28:59Speaker 01

  Yeah, I come across it occasionally.

• 29:01Lex Fridman?

  For dinosaurs, let's see what's the top post of all time.

• 29:05Speaker 01

  Oh, that's a glyptodontid.

• 29:07Lex Fridman?

  An Argentinian farmer recently found a twenty thousand years old fossilized.

• 29:12Speaker 01

  So these are, these are giant armadillo-like animals with club tails.

• 29:16Lex Fridman?

  Interesting. Wow.

• 29:17Speaker 01

  Oh, that's black beauty. That's at the Royal Tyrrell Museum. So giant eyeballs, they can either see very well, they can see a very long way in daylight, or they can see very well at night. And my suspicion is it's the latter. I think they're probably primarily nocturnal when, when they get that size.

• 29:33Lex Fridman?

  Well, not moving might be a good strategy because it's cautious because it doesn't understand what these primates are.

• 29:38Speaker 01

  Yeah. Um, but I think if it, if it starts coming towards you, if you're truly in the open, then you're in real trouble. And I'm not sure what you do. I mean, the one thing, the one advantage humans have over almost anything else on earth, there's a handful of exceptions, is we have range. I can pick up a rock and hurl it with reasonable accuracy. Most things can't do that. And animals probably don't like being hit in the face or hitting the eyes with a rock at a range. Cause again, they're not going to know how it's happened or how to respond to this. All they know is they're taking damage and that's bad. And that, that might genuinely be enough to do it. I wouldn't want to try, but again, if I was

• 30:14Speaker 01

  dumped on a plane or a prairie with nothing else but a T-Rex that was interested in me, it's worth a shot. Um, if you're in the forest, I would try and get behind a tree. They're, they're quite good at turning. There's been a couple of nice papers looking at like the, the mechanics of the foot and the ankle and how quickly they could like pivot. Um, but we're much better because we're just so much smaller. So it, it would be very kind of Looney Tunes, but I think you could go round and round a big tree, right? Yeah. But much faster than it could.

• 30:34Lex Fridman?

  Yeah.

• 30:35Speaker 01

  And so it's going to get bored or lack interest sooner or later.

• 30:40Lex Fridman?

  So let's zoom out. What did it eat?

• 30:43Speaker 01

  I mean, the, you could go for the classic joke of whatever it wanted, but the reality is, um, the relatively big herbivores that are around at the time, it's probably largely leaving them alone because again, just the classic dynamics of.

• 31:21Speaker 01

  Predators, even like quote super predators like Tyrannosaurus, they're still real animals. If you get injured and you can't hunt, that's probably the end of you. So you don't want to tackle an adult triceratops that weighs the same as you and has meter, meter and a half long horns on its head and it's potentially pretty aggressive.

• 31:45Speaker 01

  And then even the big, so the Hadrosaurus, the kind of classic duck billed dinosaurs, they're not, they're not present with any like obvious defenses. They don't have armor, they don't have horns or spikes or anything like this, but they're simply massive. Again, you know, yes, T. rex has got the teeth and the bite and even if they're a bit rubbish, the claws on the hands, but like just grappling another animal which is the same size as it, there's a risk you're going to get a foot trodden on that it's going to get off some kind of body slam or whatever. And then even if you do bring it down, you're never going to eat it. Like if you, you bring down an animal that weighs five tons, it's nearly your own mass. You're not, you're not going to eat it before it goes rotten. That's a huge amount of kind of not like wasted energy, but you've probably put a lot of effort into this and you're not getting that much reward out.

• 32:30Speaker 01

  And again, there are, again, there are exceptions. You've got things like lynx are the classic one. Lynx are not very big cats and yet they'll hunt adult deer way bigger than them. Lions hunt things like buffalo, but they're operating in a group, so it's a bit of a cheat. So there are some things that do this, but fundamentally the vast majority of carnivores tackle stuff that's way, way smaller than them. And that's what we see. Every record we have of basically any large carnivorous dinosaur where you have stomach contents, where it's like consumed something or healed bite marks, we get quite, we get a, not quite a few, there's a handful of them where there's an obvious damage to a bone in more than a couple of cases with a tooth broken off in the bone.

• 33:14Speaker 01

  And then the bone has healed over it. So you know it got away, they're juveniles, they're relatively young animals and that's what they're targeting. Um. It makes ecological sense. It's what modern animals do for very good reason. Juveniles are relatively small and weak. They don't have the horns or frills or armour or shields and other stuff. They're naive. They don't, they have, you often have to learn what predators are, or you have to learn how to avoid them, or to check the wind, or even physically see them before you know, see them kill something else before you know that they're a threat. And juveniles forage badly. Um. They're relatively inefficient, so actually they need to eat more

• 33:58Speaker 01

  for their size than an adult does. And then on top of that, they're not very experienced at foraging in the right areas. And even if they can find a good patch, the adults will often beat them up and chase them off.

• 34:08Lex Fridman?

  You're talking about juveniles across various species?

• 34:11Speaker 01

  Everything. This is just a universal pattern of being a smaller animal versus a larger, or a younger animal versus a larger animal.

• 34:17Lex Fridman?

  So, so hunting young.

• 34:19Speaker 01

  Young things.

• 34:20Lex Fridman?

  Young things is easier.

• 34:21Speaker 01

  Yeah.

• 34:21Lex Fridman?

  Because they're dumb.

• 34:22Speaker 01

  Right. They're dumb, but they're inexperienced.

• 34:24Lex Fridman?

  Inexperienced.

• 34:24Speaker 01

  But they're often, they're often feeding in suboptimal areas. So this is the place with all the best food. The adults will kick you off, so now you have to feed somewhere else. Maybe the food isn't as good, in which case you need to eat more of it, so it takes longer. Or maybe it's the one next to the edge of the forest where the T. rexes hide. But either way, you're stuck there, and then you don't really know what you're looking for, and you haven't got the armour. So guess who's getting eaten? Like, this is, again, there's lots of exceptions. You can't have nature without things like that, but this is the absolute rule of thumb for how foraging and growth and predation operate across everything from fish to starfish, as predators, starfish, praying mantis, all the way up to

• 35:07Speaker 01

  things like big cats via stuff like crocodiles. It, it's how it works. So it'd be very weird if it didn't also operate for dinosaurs. And then, as I say, we've actually got the direct evidence for this from bite marks and stomach contents. They're taking small stuff.

• 35:21Lex Fridman?

  Bite marks give a lot of information.

• 35:23Speaker 01

  Yeah.

• 35:23Lex Fridman?

  That's a powerful signal in paleontology.

• 35:25Speaker 01

  Yeah, absolutely. I've done really quite a lot of work on it, and they can tell you an awful lot if you've got the right understanding of the burial conditions, because you, weird thing that I think a lot of people don't appreciate is you basically can't take fossils at face value, particularly when you're trying to get into stuff like behaviour and ecology, because. So between the animal dying and the paleontologist digging it up, potentially quite a lot has happened. And that's where it's really easy to start misinterpreting things because if you just go, I had one like this not too long ago where I was an editor on a paper and the authors had done a pretty good job, to be fair, but it was this discussion of whether

• 36:08Speaker 01

  or not several animals were together at the time of their death. Said multiple theropods together in this quarry. And it's like, right, but there was loads of debris and you had loads of things like fish scales and other small bones. And it's like, okay, but this looks like these animals die, potentially died somewhere else. And then a flood or a river washed them into this bay or a channel or then the water level dropped and they ended up together. But that doesn't necessarily mean they were together when they died. And so just because you've got three animals together, what is potentially the story of how they got there? So you have to consider multiple explanations and then try to figure out what is the most likely.

• 36:52Speaker 01

  Yeah. Or what can you test with various bits of evidence? So there was some tyrannosaur inflicted bite marks on a duckbill from Mongolia that I worked on years ago. The specimens from Mongolia, but it was held in Japan in a Japanese museum, was working with the Japanese on it. And I'm, I'm not a taphonomist, so the study of like decay and the history of specimens, and I am in no way, shape or form a geologist. I did zoology for my degree. But the guys I was working with, like, they were really hot on erosion and damage. And they were looking at some of the way the bones had been damaged. And they're like, okay, we're pretty confident that the bite marks are sitting on top of erosion. What does that mean?

• 37:36Speaker 01

  So it means that the animal had died, and it was found in a, it was found in sand covered, but in what would have been a river channel. So this animal has died, washed downstream, ended up on a sandbank. The sand is whipping past because I've been in a sandstorm in China. It is not fun. And that's starting to etch some of the bones and damage them. And after that, there's a bite mark? After that, you're getting bite marks coming in. So that can only be scavenging. That thing has been dead and sitting out for days, possibly weeks, before something came along and chewed on it. It pretty much can't have happened any other way.

• 38:12Lex Fridman?

  And you have to take these really subtle signals to reconstruct the story.

• 38:17Speaker 01

  But then you can start piecing some other stuff together. So in this case, the skeleton is pristine. It's one of the best hadrosaur skeletons out there. It's certainly the best from Mongolia I've ever seen. Um, and all the bite marks are on one bone, the humerus, the upper arm bone, every, every mark. The, we, we went over the rest of the skeleton, nothing. And then the humerus is chewed to bits. There's bites all over it. But when you look, there's two really distinctive patterns. There's deep circular punctures. And remember what the shape of this thing looks like.

• 38:48Lex Fridman?

  Yeah.

• 38:49Speaker 01

  At the ends, and then along the delta pectoral crest, okay, it's much, much bigger in a hadrosaur. But this bit, but remember, that's where all the big muscles attach. There's all of these types of, this is from a different bone, but different animal, but all these types of close, parallel scratches. And so that looks like selective feeding, because it's using its giant crunchy teeth at the ends to get the bone off. And this is off a buried skeleton.

• 39:17Speaker 01

  And then it's got these, actually, T-Rex has really small teeth at the front of its mouth. Right, right in the front where our incisors are. They're called incisiform teeth. They look like incisors. They're a fraction of the size of the big ones. Um, and they've got a really weird flat back. And that's what these are. It's hidden this with the front of the mouth and pulling.

• 39:39Lex Fridman?

  And that's mostly for eating.

• 39:40Speaker 01

  Yeah. And that's why it's just on the delta pectoral crest, because that's where all the muscles are.

• 39:44Lex Fridman?

  Hmm.

• 39:45Speaker 01

  So it's, I always liken it to getting something like an Oreo and you take the top off. And you scrape the cream out with your teeth. I think most people have done that.

• 39:54Lex Fridman?

  Yeah.

• 39:54Speaker 01

  Right. But, but that's what it's doing. So it's got this little row of teeth. And everywhere you get lots of muscle, you get little rows of teeth together.

• 40:03Lex Fridman?

  So there's different bite marks for sort of fighting, killing, and then there's different bite marks for eating.

• 40:09Speaker 01

  Yeah. So it kills and dismembers with the big teeth up the side, and then it feeds with the little front teeth.

• 40:14Lex Fridman?

  And all of that has evidence.

• 40:16Speaker 01

  Yeah.

• 40:16Lex Fridman?

  In the bones.

• 40:17Speaker 01

  Yep.

• 40:17Lex Fridman?

  What hunting strategy does it use? Can we figure that out?

• 40:21Speaker 01

  So that comes down to the, um, to that foot stuff. Um, they're relatively efficient.

• 40:29Speaker 01

  Compared to a lot of other things, and particularly compared to the herbivores. So that means they're probably looking at long distance rather than speed. And that makes sense because even though the kind of stuff we're talking about, like I said, maybe they're getting to twenty, twenty five miles an hour. That's pretty quick, but some of the smaller stuff is going to be a lot faster than that. And remember, that's a real upper estimate, that they're probably not that quick. But yeah. They're just jogging after you. Right, but but they've got they've got the distance. So yeah, so it's much more a hyena or wolf like strategy than like a cheetah going for hyperspeed or a lion going for a relatively quick burst and it either gets you or it doesn't. And then you the people kind of end and just go, well, like, but that's ridiculous. Like they're not even that quick.

• 41:14Speaker 01

  And it's like, yeah, but if you're hunting something big, that's not that quick either. And so that's a misconception. Like when I'm talking about juvenile dinosaurs, I don't mean just out of the egg and weigh a kilo. Like a juvenile triceratops, because still weigh a ton and be the size of a rhino. They're not that fast. And again, if you get a head start on them, because as I said, I suspect they're nocturnal. So because that's the other thing, it's really hard to hide a T Rex. Even lions and tigers struggle to kind of hide in long grass. When you're three and a half, four meters tall, like you you can't hide. Maybe in a forest, but even then you're probably going to stick out and it's going to be hard to maneuver between the trees.

• 41:59Speaker 01

  And we've got big tyrannosaurs living in what we know to have been relatively open environments. Maybe there's some stands of trees, but it's not like a woodland or a forest or anything like that. So they're living in the open and surviving in the open. So they've got to have a way of doing this. And I think it's either or some combination of being nocturnal. So it's you relatively easy to sneak isn't quite the wrong word, but approach things to cut the the distance down for your initial strike and then just run in them down. Because yeah, maybe a one ton triceratops or one tranhadrosaur is rather faster than you.

• 42:36Speaker 01

  But if you've covered the first couple of hundred meters to get up to your top speed before they start running, then you're probably much closer to them. And then will they exhaust faster than you'll keep going? Well, probably not a hundred percent of the time. No predator's that effective, but I suspect that's what they're doing. And it fits with what we know of their size, their vision. They've got a very good sense of smell. Again, that makes sense at night. It makes less sense if you're diurnal and operating primarily in the day. And you've got to hide this thing. And then we know they're pretty efficient versus relatively fast, but not that efficient prey. Well, there's a bit of a debate of scavenger versus hunter. They're obviously both.

• 43:18Speaker 01

  A, because we've got things like the bite marks I just described, which is pretty much definitive scavenging. And then we've got the healed bite marks with T-Rex teeth buried in bones, which is pretty much definitive active predation. So we've got evidence of it doing both. But can we possibly figure out what was the primary strategy? That gets much harder. My guess is they're probably still primarily actively carnivorous. Because if you look at stuff that's reliant on being a scavenger, I mean, the true scavengers, like the vultures and condors and stuff like this, you have to be ultra-long distance, very energy efficient travelers. You know, they're thawing, soaring in thermals. They're barely using any energy to fly.

• 44:03Speaker 01

  It's really hard to get very far. How far were they spread? Where did they, where did they live? So the ones we found, you've got them from Alberta down to probably New Mexico. There's some, I want to say there's some Tyrannosaurine, so very close to T-Rex teeth, that may or may not be T-Rex in New Mexico. There's similar teeth in Mexico proper, down in Cohuila. So about halfway down Mexico. Mongolia also or no? So Mongolia, you have a thing called Tarbosaurus, which is a very, very close relative of T-Rex. It's the nearest. Species or nearest genus that we have.

• 44:45Speaker 01

  But T. rex is probably occupying almost all of Western North America. So at times the east was kind of split off and and separate.

• 44:53Lex Fridman?

  But the entire surface of earth had dinosaurs on it.

• 44:56Speaker 01

  Oh, yeah.

• 44:56Lex Fridman?

  Most of it.

• 44:57Speaker 01

  Yeah, we we've got them in Antarctica. We've got them in Antarctica, even close to the mass extinction event.

• 45:02Lex Fridman?

  Just an insane number of dinosaur species all over the earth. Just the same kind of variety we have in the animal kingdom today. You just have in the dinosaur.

• 45:12Speaker 01

  I mean, this is this is like, how many dinosaur species were there? I mean, I basically wrote an entire book chapter about this because there's so many. But this would make the number high, but this would make the number lower. But this would make the number high, but this would make the number lower. Counter versus counter arguments that you can guesstimate almost any number and probably be very accurate or very far out.

• 45:36Lex Fridman?

  Yeah, but we should say that a large number of dinosaur species are constantly being discovered.

• 45:40Speaker 01

  Yeah, so we've named, give or take in the realm of fifteen hundred, sixteen hundred valid species. That is, not everyone agrees on every species, but most people would be satisfied with that number.

• 45:54Speaker 01

  But we also name in the realm of forty to fifty a year, and we've been doing that for at least the last ten, twelve years. That number is rocketing up, shows no signs of slowing down. There's loads of air, like, we still never really explored India very much. We're starting to find entirely new beds in places like Ecuador. Argentina, we know, has a ton of stuff, but we've never excavated there very much. Australia, we know there's a ton of stuff we haven't excavated there very much. So there's lots of places, even now, to still go through.

• 46:26Lex Fridman?

  This is a good moment to take a brief tangent and look at paleontology. So how how do we how do we find these fossils? What's the uh, what's the magic? What's the science, the art?

• 46:35Speaker 01

  The same way, more or less, that people did in the seventeen fifties or whenever you first start getting them, that there's. For dinosaurs in particular, but this is true of the vast majority of stuff. There's essentially two ways of doing it. The simple one is where you have quarries of particularly things like lithographic limestone. So the printing limestones or stuff that's very similar to that. Sometimes it's often volcanic. You get these super, super, super fine layers of sedimentation. And that's where you get these places of exceptional preservation. Whenever you see like the feathers or almost always whenever you see feathered dinosaurs. It's like, oh, we got the skin, we got the claws and like the whole skeleton's laid out.

• 47:20Speaker 01

  So archaeopteryx being like the, the first bird in this absolute classic example. It's from these beds. And there you find them by basically splitting limestone. We don't usually dig for them. It's because there are quarry workers and people who are already doing this because the stone is useful. Because there might be one decent fossil for every, you know, few hundred tonnes of rock you shift. In which case you could get every paleontologist in the world there for a couple of years and you wouldn't find very much. You rely on the fact that there's hundreds of guys doing this constantly. And then sooner or later they'll find something and then you've got it. That's the super easy way. The only slightly more complicated way is you go to somewhere where geologically we know it's the right age.

• 48:05Speaker 01

  And it's the right kind of rock. And ideally fossils have been reported from there before. And again, you know, geologist Matt, all the world's geology years ago in quite a lot of detail. There's, there's gaps, there's places where we don't have the details, but in general we know. And then you go there and then you walk around and you look and that's basically it.

• 48:26Lex Fridman?

  And you're looking for something that's sticking out of the rock.

• 48:28Speaker 01

  Yeah. So you always get the, so there's this constant, and I think, you know, borderline myth of the idea that dinosaurs and mammoths and lots of other fossil things like entered lots of indigenous cultures. Because it's impossible that the guys were wandering around, say Dakota. And the Native Americans didn't come across some dinosaur fossils. That I'd agree with, it's pretty much impossible. They didn't come across some dinosaur fossils. Did they come across a whole skeleton laid out on the ground? No, because those don't usually exist. Because even if they're tougher or it doesn't matter if they're tougher or weaker than the surrounding rock.

• 49:11Speaker 01

  Dinosaur bones are, you know, in some way, shape or form, they're lithified, they they've turned to rock. And they will absorb some of the minerals from whatever they've been buried in. And so even in places like Mongolia and northern China, where I've been to, where actually the the fossil bone is quite a lot tougher than the sandstone that it's embedded in. Like you can find a bit of bone and pull it out, like almost like rub it with your hands and the the sand comes off. There's your bone, they will decay pretty quickly, you know. Sandstorms, you know, sand just etches stuff. Um, the tiniest bit of moisture, particularly in winter, gets into the cracks, bones are incredibly porous. That freezes, that expands, that cracks, bones just shatter.

• 49:55Speaker 01

  And yeah, you find shattered bone on the surface everywhere. What you rarely find is a decent bone on the surface, let alone a skeleton. So there has to be something that's sticking out just a tiny bit. So that you can see it, but it's still buried. Right. And it and it happens, the the the greatest one that I saw or that that I didn't see it happened by with a friend of mine when we were in um northern China. And he went, yeah, I can see a bit of a claw sticking out of a hill. And it was, it was like this this much, you could see, you know, less than a centimeter coming out of a hillside. And it's like, so, you know. That's the dream, right? Dig a little bit and there's a little bit more, dig a little bit, there's a little bit more, dig a little bit, there's a little bit more, okay.

• 50:37Speaker 01

  And then the system we were running there is some guys were searchers and some guys were diggers. So he and I were searchers, we're told, okay, you guys, you guys, he found it. You found something, go and look for something else, we'll dig it out. And so we come back a couple of days later and check in on the digging team. So what is it then? Oh, it's a complete skeleton. And it was, it was a thing, very, very close relative of um Velociraptor. Ended up naming it Linhe Raptor, so the raptor from Linhe, which was the nearest town. And it was, yeah, the legs were a little messed up because water had got to them and the end of the tail was missing. And that was about it. So like ninety plus percent complete skeleton and it had been found with.

• 51:19Speaker 01

  You know, five mil, a couple of sixteenths of an inch of bone sticking out of a hill. And that's what you want, because every so often behind that is a whole skeleton. If you're looking for skeletons on the surface, they're gonna be gone before you get to them.

• 51:33Lex Fridman?

  And when it's a near complete skeleton, you you did a show of terrible lizards on Stan.

• 51:39Speaker 01

  Oh, yeah.

• 51:40Lex Fridman?

  T-Rex fossil that sold for thirty one point eight million dollars.

• 51:43Speaker 01

  Sane sum of money.

• 51:44Lex Fridman?

  So that that's a nice sort of big adult T-Rex. So looking at a fossil like this.

• 51:51Speaker 01

  Yeah.

• 51:51Lex Fridman?

  So for thirty one point eight million dollars, what's the excavation process? For when you have a claw sticking out, like you were mentioning, and getting that whole thing out without damaging the bones? What can you say about that process?

• 52:03Speaker 01

  So it depends where you are. It depends how many people you've got. It depends on your budget and it really depends on the rock. So again, like going into China or Mongolia, where this little guy's from. The bone tends to be relatively strong compared to the sandstone that it's in. That also, that means that A, it's fairly tough and resistant.

• 52:26Speaker 01

  But it also means that it's really easy to dig. Like, again, I've dug stuff by almost like pulling it with my hands or like getting my fingers in. Getting something like a chisel or a hammer, you can just cruise through this rock.

• 52:40Lex Fridman?

  But like, you have to be really careful not to touch the bone, I guess.

• 52:43Speaker 01

  So it depends how how strong it is. So again, some bone is incredibly strong, some isn't, because they've all fossilized differently. What we're usually doing is applying glue to it, though. There's this wonderful stuff called paraloid and it's a special glue for fossils. And as I said, bone super porous, so it's really good at sucking up liquids.

• 53:05Lex Fridman?

  Oh, so you're basically filling it with glue, so it like makes it stronger?

• 53:08Speaker 01

  Yeah, and paraloid is really great because you can dissolve it with acetone. And it basically doesn't react with anything. So you can fill your fossil with glue, but then if you want to take all that glue out, you can pretty much just dissolve the glue back out again.

• 53:22Lex Fridman?

  Very cool.

• 53:23Speaker 01

  So, yeah, what you would normally do is for for something, say in China, where the rock is relatively soft. And the bone's relatively tough and where we don't have any like manpower and shipping problems, which is a real issue in other places, you basically map out where you think the skeleton's going. So in the same way that you were doing it, like, you know, if you can imagine like a cake or something and someone said, I put a toy dinosaur in there and you've, you've, you've got to find it without damaging it. So like, well, you'd stick your finger in the cake and just kind of dig until you hit the edge of it. And then you go in somewhere else and go in. And that's what we're doing. We're just going in from

• 54:06Speaker 01

  kind of all sides. And once you've hit three or four bones, you kind of know which way it's, it's going into the hillside. Usually, sometimes they're very weird and mixed up. And then you can just like almost trace the outline of it. And then you'll just dig all the way around that, which might involve taking the top off a mountain, depending on where you are in the desert, it tends to be a bit easier. But yeah, we, we've had stuff where like the first three days is just 10 people with pickaxes just digging a hole to get down to the right level.

• 54:36Lex Fridman?

  But sometimes the excavation requires like large equipment, right?

• 54:40Speaker 01

  Yeah, we use jackhammers and stuff. We've, we've used a backhoe. We've just literally driven it into the desert and just dug a big hole next to the, to the fossil. And then the classic thing of covering it in a plaster of Paris jacket, strip, strips of burlap sacking, plaster of Paris and some water, wooden beams, if you want to make something really big and really solid and just basically wrap it all up and then take it out. And that's, again, that's what they were doing 150, 200 years ago, that, that, that hasn't changed. Where it gets more complicated is if you've got really hard rock, it's very hard to get through, particularly if the bone is fragile, then it becomes difficult because if you

• 55:23Speaker 01

  want to like get a jackhammer in, the vibrations means you're going to shatter your bones before you've even cut through the rock. So then you might be down to doing it manually.

• 55:33Lex Fridman?

  And then it was like.

• 55:34Speaker 01

  Yep. Hand, hand chip, chipping it out. Yeah. The, the other, the other way you end up with that is. Like the classic Jurassic Park thing, like the, the, was it the second scene? And they're digging in the desert and there's the whole skeleton laid out and five or six guys all, all digging, digging around it and exposing it. And that's actually quite common in the States. And the reason is, uh, huge amounts of those excavations are being done on government land, they're national parks or whatever, or, or, or protected land. And very often the rules are you're not allowed wheeled vehicles. Full stop at all to protect the environment. You can walk in and walk out, but you can't drive.

• 56:16Speaker 01

  And it's like, well, right, when we're in the desert in Mongolia in China, uh, China or Mongolia, and we're allowed to do this. Literally, yeah, my, my boss drove into town, hired a guy with, with a J C B. He drove out, picked it up with the bucket, drove it back into town and put it on the back of a flatbed and we drove it to Beijing. If you're out in a protected area and you can't, you've got two choices. You can take it out by hand, but that means it's got to be light enough that half a dozen people can lift it. Which if it's a block of stone the size of this desk, you know, couple of meters by a couple of meters by a meter high, is basically impossible. So that means you either got to carve chunks off. So take the head off, take the arm off and whatever.

• 56:59Speaker 01

  And you can get it out that way, but it's not ideal. There's always the risk of breaking, you're losing some information. And if you want to make a really spectacular display, you don't want to join through every big bit of bone, you, you want to show the public one, one piece. So the alternative is to get rid of every bit of rock you possibly can to make it light enough to helicopter it out. And so normally, so in China, if we hit, yeah, if we hit that bit of bone going in, we're just like going in round the sides until we've hit it. Take the top off, take the bottom off and just take it. So the skeleton is completely encased in rock and it's as safe and secure as it can be. And then we'll do the preparation work back at the lab.

• 57:42Lex Fridman?

  That's heavy though, that's real heavy.

• 57:44Speaker 01

  If you're going to have to lift it with a helicopter and they've got a weight limit of only a couple of tons. Or if it's not, then you need to pay twice as much for a much more expensive helicopter. Then you take off every gram of rock that you think you can to get the weight down. So you can ship it. So it varies massively. Yeah, something the size of Stan. That's that's months of work. You're probably doing that across three or four years with a team of half a dozen people.

• 58:10Lex Fridman?

  So can we just talk through, because just using Stan as a case study. Stan was first discovered in the spring of nineteen eighty seven by amateur paleontologist. Well, Stan Secason in the Hell Creek Formation near Buffalo, South Dakota.

• 58:24Speaker 01

  Yeah, but it was the Larson Brothers from the Black Hills Institute who dug it up. And so they're they're a commercial outfit. So they dig stuff up to sell it, but they also make casts and sell them. This, oh, I brought my others. I do have a cast, a cast of one of Stan's teeth. So like you can buy cast of Stan's teeth, you could buy cast of the head. You could buy the whole skeleton.

• 58:46Lex Fridman?

  It's a famous skeleton.

• 58:47Speaker 01

  You you see Stan in a whole bunch of different places. There's a there's a stand just up the road from here at Oxford. Oxford's got a cast of Stan.

• 58:54Lex Fridman?

  Oh.

• 58:55Speaker 01

  I was just at Lyme Regis, a famous fossil locality in the south of the UK. A couple of weeks ago, one of the fossil stores has a skull of Stan in the window. So Stan Stan turns up again and again and again.

• 59:06Lex Fridman?

  So the process is written here involved removing the overlying rock using heavy equipment like a Bobcat.

• 59:11Speaker 01

  Yes, we call that the overburden, the extra stuff. That's all the rock that's sitting above the layer with our fossil in. And when you're lucky, that's a foot of sandstone and you shovel it out in an hour. And I've seen guys in South America, there was a team in Argentina. I think it was my old boss, Ollie Rauch, showed me this. And they took like twenty, thirty feet off the top of a hill to get down to this fossil. You know, so something, you know, probably half an acre in size, twenty, thirty feet of rock.

• 59:44Lex Fridman?

  I was, it's incredible.

• 59:46Speaker 01

  Yeah.

• 59:46Lex Fridman?

  I wonder if you could speak to some of these other components. Carefully extracting each fossil bone by hand with picks and brushes. Plotting and diagramming the bones using a grid system at the dig site. Wrapping the bones in burlap and plaster for safe transport to the BHI lab. Some of the stuff you've spoken to, what's what's with the diagramming, what's with the plotting?

• 1:00:04Speaker 01

  So yeah, so you may well have seen something like this for archaeology shows or something like that. Nowadays, again, tech's getting better. People are using drones and stuff for this or taking hundreds of photos and then building photogrammetry models. You've just got a 3D model in the computer.

• 1:00:21Lex Fridman?

  Or just kind of modeling what we're looking at here.

• 1:00:23Speaker 01

  Yeah, but but where you found everything. So it goes back to that stuff we were saying about the process of fossilization or the or the process of what's happened to that animal from death to discovery is, okay, it, right, a classic thing is bones being in a line. So you can imagine if, you know, bones are lots of weird shapes, but mostly, or they're certainly lots of bones, ribs, arms and legs, things like this, they're quite long bones. So if they're in a current, they will tend to spin in the axis so that they are facing the current. So if you're finding all the bones are in a line, that probably tells you that this thing has had quite a lot of water washing over it.

• 1:01:01Lex Fridman?

  Hmm, got it.

• 1:01:02Speaker 01

  You're then probably going to be missing most of the small bones because the big heavy bones won't be shifted by that current, but maybe the small ones will.

• 1:01:09Lex Fridman?

  Oh, so you actually model where the bone, where where you're likely to find the bones, the big bones, the small bones.

• 1:01:14Speaker 01

  So it might, it might tell you where to go and dig further down the hill, quite literally, but it could also just tell you, okay, this thing, there's no way this thing died here. It absolutely got moved. So we need to factor that in when we're trying to interpret it. Or we've got this one weird bone and we can't work out what on earth it is. Well, maybe it's from something else because if we know a whole bunch of stuff washed together, maybe that's a random bone from a different animal.

• 1:01:40Lex Fridman?

  Yeah, maybe that was eaten or there might be a different story if it was washed like you like you were describing.

• 1:01:45Speaker 01

  Any of that kind of thing. So that's where you want to have as much information as possible.

• 1:01:51Lex Fridman?

  It says here, once at the lab, the bones underwent more than 30,000 hours of cleaning, preservation, restoration and documentation. And Stan's skeleton is notable for its high degree of completeness, about 70% by bulk, 63% by bone count, and the exceptional preservation of its skull, which has become a scientific standard for the species.

• 1:02:10Speaker 01

  Yeah. So there's this unbelievably beautiful skeleton, Boreal Pelter. This is, this is a helicopter lift. Um, absolutely phenomenal preservation from from Northern Alberta.

• 1:02:23Lex Fridman?

  What is this thing?

• 1:02:24Speaker 01

  Its full name is Boreal Pelter Mark Mitchelli. And it's called Mark Mitchelli, named after Mark Mitchell, the preparator, who basically spent, I think Mark spent the thick end of two years on this. Like this was his job. And he did other stuff as well. He's doing some other prep. He's doing some field work. But Mark basically went in. Every day, nine to five, cleaning the rock because the rock was hard and the bone was soft and it's extraordinarily well preserved.

• 1:02:51Lex Fridman?

  Boreal lapel is a genus of plant eating armored dinosaur sure as hell looks armored. This is an incredible preserved specimen from the early Cretaceous period, about 112 million years ago, found in what is now Alberta, Canada. Amazing. Look at this thing.

• 1:03:08Speaker 01

  So boreal pelter is one of the ones where we've even got some of the evidence of patterning and it suggests that it's darker on top and lighter underneath. So this illustration, I think that's, yeah, it's Julius Chitoni did that. He's a Canadian paleo artist. And so that color pattern is roughly accurate.

• 1:03:25Lex Fridman?

  Oh, wow. So this is true to color. Yeah. So we can figure out colors.

• 1:03:28Speaker 01

  Give, give or take some very large uncertainties. It's going to be something like this.

• 1:03:35Lex Fridman?

  That's so awesome.

• 1:03:36Speaker 01

  So these guys are.

• 1:03:37Lex Fridman?

  It's hard to eat that.

• 1:03:38Speaker 01

  Near enough armored pine cones. Yeah, though it's very much the adult condition. Uh, the juveniles seem to be far less, if not unarmored.

• 1:03:46Lex Fridman?

  We're back to the juvenile thing.

• 1:03:48Speaker 01

  Right. So, right. So, so, but that's why we, that armor is absolutely going to be effective as anti predator, but it's probably evolved primarily for combat and display between members of the species. Cause otherwise, if this stopped you being eaten, the babies would have it.

• 1:04:03Lex Fridman?

  This fossil is considered one of the best preserved dinosaur specimens ever found with armor, skin, keratin sheaths, and even stomach contents, all intact. Incredible.

• 1:04:14Speaker 01

  Yeah.

• 1:04:15Lex Fridman?

  And so for that, he really did the work.

• 1:04:16Speaker 01

  And also found miles and miles and miles out to sea or the, the paleo sea. So this is from a site which normally gives us big marine reptiles. So predatory pleseosaurus and ichthyosaurus and then, um, uh, mosasaurus and stuff like that. And then it turned up an ankylosaur. Well, nodosaurus in this case.

• 1:04:36Lex Fridman?

  Yeah. Wow. This is incredible.

• 1:04:38Speaker 01

  Yeah.

• 1:04:38Lex Fridman?

  So, okay, let's complete the journey of Stan to the museum to like, you get, you get to the process of cleaning everything, stitching it all together.

• 1:04:46Speaker 01

  Yeah. Like Mark and like that suggested, you know, this, this can be even on an animal that size. Boreal pelter is, you know, four or five meters long. We've only gone to got the front two thirds of it. Yeah. This, this can be like needle level stuff.

• 1:04:59Lex Fridman?

  That's how you get to the 30,000 hours.

• 1:05:00Speaker 01

  Yeah, exactly that. If it's that quality and you want to get everything open and then something like Stan. Actually really complicated skull, the skull's full of lots of little bones, the bones are really fragile, so that just adds to the time. I mean, at least the ankylos, the skull is just this giant solid block of bone, which makes life a little bit easier. So yeah, they're gonna put those hours in and that's really gonna help them sell the animal, which is ultimately what happened. I mean, Stan sat in the Black Hills Institute for decades. I mean, eighty seven and they sold it in like twenty twenty. So they had it for thirty years, uh, sitting in their kind of little museum. And then my understanding was basically the brothers broke the company up and that's why they sold it.

• 1:05:44Lex Fridman?

  Yeah, but it was still incredibly surprising that it was sold for thirty one million.

• 1:05:48Speaker 01

  Yeah, I mean, far more than I think anyone thought it was going to. I mean, I I liken, you know, if you're not buying like teeth or an ammonite in some small fossil shop, you know, when you're buying, talking about things like whole dinosaurs and whole tyrannosaurs. I think it's a bit like the art market in it's worth what people will pay for it. And so, you know, plenty of T. rexes had sold for a few million dollars and therefore everyone thought it would might be five. You know, ten would be an absurd sum of money and then, yeah, it it went for thirty and it's like, okay, well, two, I was gonna say, someone wanted it that bad, but clearly not two people wanted it that bad, because if only one guy is prepared to bid thirty, then it goes for,

• 1:06:32Speaker 01

  you know, a million more than the next highest bidder, but presumably two people, if not three, bid it to get that high.

• 1:06:40Lex Fridman?

  Yeah, it was anonymous at the time, but now it's Abu Dhabi's Department of Plush and Tourism came out.

• 1:06:45Speaker 01

  I know they've got it.

• 1:06:46Lex Fridman?

  And uh, and then that record has been since beaten apparently by uh.

• 1:06:51Speaker 01

  Apex, the the stegosaurus, which I still haven't seen, though a friend of mine has sent me some photos of this thing.

• 1:06:58Lex Fridman?

  Is it impressive to you, this thing?

• 1:06:59Speaker 01

  Yeah, not especially. That's why I can't imagine that it sold for that much. It's a really nice stegosaurus. It's pretty big stegosaurus.

• 1:07:08Lex Fridman?

  What preserve?

• 1:07:09Speaker 01

  I've seen other very good stegosaurus and I don't understand why that's worth that much more than something like Stan. But it shows you the market. So, so we're here in London. There's a stegosaurus called Sophie in the Natural History Museum in London. Sophie is a young animal, so she's not very big. I mean, it's a sizable specimen. I'd say five-ish, six meters off the top of my head, total length. But Sophie's like truly exceptional. Like there's a couple of plates missing, a handful of ribs, a couple of bones in the tail. I think a couple of toe bones. Like this is by far the most complete stegosaurus out there. That sold for, I think, two hundred and fifty thousand pounds, so maybe four hundred thousand dollars about a decade ago.

• 1:07:53Speaker 01

  So this has now gone up like a hundred fold for an animal which is quite a bit bigger, but is way less complete.

• 1:08:04Speaker 01

  So I, for me, those two things kind of balance out. Because size is always impressive and that's what the public likes, but also a complete one is better than a half a one or two thirds of one. So yeah, so how has the price gone up a hundred or from? Yeah, four hundred thousand to forty million in ten years. For roughly the same thing.

• 1:08:25Lex Fridman?

  A T-Rex is a little bit more epic than.

• 1:08:27Speaker 01

  Well, that's the thing. T-Rex has a massive premium on it because it's, yeah, stegosaurus is one of those top tier, you know, it's, you can virtually do the list, you know. T-Rex, triceratops, diplodocus, brontosaurus, stegosaurus. It's in that first six or seven. Okay, these days velociraptor, thanks to Jurassic Park. But it's like, it, right, but you know, there's, that's the list of like seven or eight things that any random human who doesn't care about dinosaurs and doesn't know anything about dinosaurs, but they've probably heard of them. You know, stegosaurus is in that list and would have an idea of what it looked like. Oh yeah, it's got like the big stuff stuck along the back, you know, you, you'd get that answer from almost any, you know, ninety-nine percent of people on the street.

• 1:09:12Speaker 01

  But yeah, it's, it's not a T-Rex. So how it's worth, yeah, fifty percent more. And it's not even a particularly complete skeleton apex to my understanding. Like I I don't I don't get it.

• 1:09:26Lex Fridman?

  Actually, um, since we're on the topic of money, if I gave you, let's say, ten billion dollars, how'd you spend it? You were forced out. I forced you to spend it on dinosaur related things. How would you spend it?

• 1:09:38Speaker 01

  Um, I mean, I'd probably drop half a billion or so on the best museum you'd ever seen.

• 1:09:44Lex Fridman?

  So put together a museum. You're like one of the great communicators, one of the great scientists. And so like you would want to push forward the the whole field. And one of the ways to do that is a great museum.

• 1:09:55Speaker 01

  Yeah, but you wanted. So it is twofold because, yeah, there's the communication and the education part of it, which is something I'm I'm massive on. And I think research is pointless if you don't communicate it at some level. I'm not saying everyone needs to communicate everything. If you're working on the nuances of a calculation of the volume of a black hole or something, yeah, probably doesn't need a press release or a new museum exhibition, but fundamentally, we should be talking about our work. Um, but also you got to store this stuff. Um, many fossils are fragile. They need to be kept, not necessarily in climate control, but at least you want a basement that is much more even than, you know, just sticking it in a box in a warehouse somewhere.

• 1:10:36Speaker 01

  So you've got to be able to store this stuff to be able to study it, or it's kind of pointless. But with the rest of that money, I'd buy a ton of land, like the, the, you know, quarries that gave us archaeopteryx in in Bavaria and have given us a ton of other stuff. I've worked on a load of pterosaurs, the flying reptiles from there. These these stuff are mostly commercially run or just straight up privately owned and not being commercially run. Someone's just inherited it. It's just sitting on this stuff.

• 1:11:05Lex Fridman?

  So if somebody's building stuff on land, does that threaten like the damage of of the possibility of discovering something on it?

• 1:11:12Speaker 01

  It's it's more that they're not necessarily exploiting it with fossils in mind.

• 1:11:16Lex Fridman?

  Presume you have to balance the search efforts and then the land.

• 1:11:21Speaker 01

  Yeah, but you know, one billion on its own would go a very, very long way, almost infinitely, if you're just creaming off the interest and then funding excavations and supporting scientists who are already embedded in other museums or other universities or other research institutes.

• 1:11:37Lex Fridman?

  So the rest is for buying up land so that those people can do the work.

• 1:11:40Speaker 01

  Yeah, you you look at somewhere like, you know, Brazil and there's, I can never remember the name of it, but there's again, one of these zones of exceptional preservation where superlative pterosaurs, fish, we've had a handful of dinosaurs and a whole bunch of other stuff has come out. And it's just a giant commercial mining operation. And yeah, when they hit a fossil, when they think they're close to it, yeah, they stop and pull it out and they'll send it to a museum and more often they'll sell it to a museum. And museums only have so much money, whereas what if I owned that quarry? And then I made sure everyone who worked there was trained and got a bonus every time they found anything. And then I just handed everything they dug up straight into a museum.

• 1:12:20Lex Fridman?

  So there would be some element of crowdsourced paleontology.

• 1:12:23Speaker 01

  Yeah, but it's it's more that like no researcher ever needs to spend money to access that. No museum needs to go and find a new donor to give them half a million, to go and buy this one specimen, knowing that it might still go. Yeah, to some Silicon Valley billionaires foyer or whatever. It's like, well, I own the land, so it's mine. So problem solved. Like, that that's what's in my head.

• 1:12:49Lex Fridman?

  It just would be wonderful to scale up the effort to where we can map out the whole sort of story of this time, because it's such a fascinating time in in in the history of Earth.

• 1:12:59Speaker 01

  I've jokingly written a couple of times about how all science funding in the world should go to paleontology. And the idea being that like, yeah, if you want to investigate black holes or neutrinos or

• 1:13:15Speaker 01

  chemical crystallography or panda genetics or whatever it is, you can do that anytime you want. Like that, that's not going to change a million years from now as it will from tomorrow.

• 1:13:33Speaker 01

  But fossils are in places that erode, and if we don't dig them up, they're gone. So we should dig all the fossils up now, and then we've got forever to study them. But if we don't dig them up now, who knows? You know, maybe there was something twice the size of T-Rex and it sat on a hillside for six months, and then the wind got to it and it's gone. And that was the only one that ever preserved. Well, we'll never know now. To be clear, this is a joke. I'm not suggesting we should stop doing cancer research and physics and other things. But, but it is, we're, we're in a fundamentally different field where our science is literally disappearing.

• 1:14:10Lex Fridman?

  Yeah, I mean, there's, I know it's a joke, but there's some truth to it. And, uh, uh, on the flip side, one of the things, one of the hopes is that technology will somehow ease the search and discovery process. But as you said, so far, most of it.

• 1:14:24Speaker 01

  Yeah, I mean, yeah, you know, Jurassic Park 93, you've got that little scene where they've got the, like thumper or something they call it, and it, it hits the ground and seismic. And then they go, look, look, here's the whole skeleton. Yeah, they've tried it. It, it doesn't really work. Um, we've tried looking for stuff with drones. That helps you getting into some inaccessible areas, but until the resolution's probably better, you've still got that problem of like looking, you know, with human eyes, which are binocular and being able to, you know, just tilt your head completely changes how you see something in a way that flying over just, just won't.

• 1:15:04Speaker 01

  Um, I know they've tried looking so, because the bones are porous, they tend to suck things up. So actually dinosaur bones can be really radioactive if they're in areas where there are things like uranium. So yeah, there are drawers which have lead boxes around them and stuff like this for dinosaur bones or just signs saying, do not handle. They're very low level radioactive. Like you'd have to like stick it in your pocket for six months to, to run any real risk. But they're radioactive, much more so than the background. So can we do that? Hmm. Turns out not really.

• 1:15:38Speaker 01

  So again, may maybe tech will advance.

• 1:15:41Lex Fridman?

  But for now, humans are quite incredible.

• 1:15:43Speaker 01

  Yeah, we are, but also paleo is kind of at the bottom of the pile. You know, there's not many of us. We don't have a lot of funding. It takes real money to adapt stuff. So, you know, like we're scanning stuff with MRIs and things like that in hospitals. But it mostly doesn't work very well because the problem you've got is, like I said, the bones take on some of the properties of the minerals in which they're embedded, which means their density is really similar. And things like MRIs or seismic activities basically looking for differences in density. Well, if it's the same density as the, you know, it's like I put some green plasticine in some blue plasticine. There's going to be a bit of a join and they're going to be very, very slightly different.

• 1:16:28Speaker 01

  But ultimately you're not going to be able to detect that through most means if you're looking for density or mass or anything like that.

• 1:16:35Lex Fridman?

  Well, I personally think that there's few things as important to understand as the history of life on Earth. There's like books, right? There's like, or maybe you could think of as chapters. And then one of the chapters is the time of the dinosaurs. And then there's a great extinction.

• 1:16:52Speaker 01

  I mean, that's not a million miles off to, I think Darwin had an analogy like that of we've, we've, we've got a few words on a few pages spread out. But between them, you get an idea of what the story is and where it's going.

• 1:17:07Lex Fridman?

  I think what humans don't quite realize is we may end up being just a chapter in a book. It might be our extinction event self-created, perhaps a nuclear war, perhaps robots take over, perhaps we don't know.

• 1:17:21Speaker 01

  Well, or dumb luck. I mean, the dinosaurs were doing absolutely fine until a dirty great rock hit them. And you, you can't, you know, Ben Affleck and Bruce Willis movies aside, there's only so much you can do about that.

• 1:17:35Lex Fridman?

  You take that back. There's nothing they can do wrong.

• 1:17:39Lex Fridman?

  All right, uh, quick pause, bathroom break.

• 1:17:42Speaker 01

  Yeah, yeah, yeah.

• 1:17:44Lex Fridman?

  We've taken a few tangents, but let's, uh, continue on the thread of T-Rex.

• 1:17:49Speaker 01

  Yeah.

• 1:17:49Lex Fridman?

  Go, go to the skull.

• 1:17:50Speaker 01

  Yeah.

• 1:17:51Lex Fridman?

  So, uh, the skull of T-Rex is iconic. You, you describe it as being incredibly robust and overbuilt.

• 1:17:57Speaker 01

  Yeah, there's a lot of bone on there. Uh, as I've been mentioned, a couple of other things like Giganotosaurus, so this, you know, giant carnivore. Uh, if you put Giganotosaurus T-Rex in, that's the one. So that's the, that's on my old blog. It's not my image.

• 1:18:11Lex Fridman?

  What are we looking at on the left and the right?

• 1:18:12Speaker 01

  You got T-Rex on the left in orange and Giganotosaurus on the right in red. As I said, they're pretty similarly sized, but just look at the robusticity. Like the front of the snout of T-Rex is all bone and yet the major opening, this is a thing called the antorbital finestra, the opening in front of the orbit. It's absolutely massive in Giganotosaurus. It's like half the skull. The opening at the back of the skull is much bigger. The opening in the lower jaw is much bigger and actually the jaw, what you can't see side to side is much thinner. So the heads are the same size and as animals, they are about the same linear dimensions. But you can just see there's just way more bone in the T-Rex.

• 1:18:52Lex Fridman?

  It's incredible.

• 1:18:52Speaker 01

  So this is like, it's not overbuilt. It's obviously, it's evolved that this is the right amount of bone for the stresses and strains for what it's doing and how it's acting. But you compare it to anything that's not a very large tyrannosaur and suddenly you see just how much bone has gone into it. It is a very large, it's an absolutely large head, but it's a very heavy head with a lot of bone. And a lot of that bone is there to resist all the forces of all the muscles because it has this giant, super powerful bite, which again, you can see in the teeth.

• 1:19:21Lex Fridman?

  So the bone and the muscles kind of evolved together.

• 1:19:23Speaker 01

  Yeah, yeah, yeah.

• 1:19:24Lex Fridman?

  Bigger and bigger and bigger. So you need this kind of structure for the power that Crush has.

• 1:19:29Speaker 01

  So one of the big things, uh, tyrannosaurs have, uh, and this goes all the way down to the, the, the earliest tyrannosaurs were like our size. Like little ditty things, like two, three meters long, be a meter and a half tall. Um, but they have fused nasals. So the pair of bones that in us, there's not a lot there, but obviously in something like a dog or something like a baboon with a long nose, it's like the whole top of the snout. And there's two, one each side. In Tyrannosaurus, they fuse together. So they forms a solid bit of bone. So the whole top of the nose is solid. And then that makes the skull just fundamentally more rigid and able to take more power through it. The very early ones weren't super biters, I suspect, but they do, but they do have the little flattened teeth at the front. So I strongly suspect.

• 1:20:14Speaker 01

  The fuse nasals, at least originally, is for resisting that. Because again, if you've got a long nose. And you're pulling with quite a lot of force at the very tip, that's going to bend your snout. So strengthen that.

• 1:20:24Lex Fridman?

  Can you speak to the evolution from the smaller to the bigger of the T-Rex? What, what were some of the evolutionary pressures? What like, what, what's the story of the?

• 1:20:32Speaker 01

  So Tyrannosaurus go back to the middle Jurassic. So Tyrannosaurus around for a hundred million years. So from about a hundred and sixty ish, a hundred and sixty five ish million years till the extinction. Sixty six point five, I think is the current dating on that. So yeah, you've got a hundred million years of them. And the middle Jurassic annoyingly is probably the bit of the Mesozoics, the whole dinosaur period that we know the least of. Just by chance, we just don't have many rocks exposed of the right age that are fossil bearing. But we got two or three Tyrannosaurus from that time. And yeah, they're, they're really quite diddy. Yeah, they'd be chest high to us. Two or three meters long, including the tail, probably more like three, a lot of them.

• 1:21:14Speaker 01

  Um, little heads, long arms. They, they look like every other carnivore going. There's, there's not a lot special to them. At this point, they've only just separated from their nearest groups, which is actually something like the ancestors of Giganosaurus, actually.

• 1:21:32Speaker 01

  They do have the fuse nasals early on. They do have these special little teeth at the front of the jaw very early on. They're feathered early on. Definitively, we have.

• 1:21:42Speaker 01

  Skeletons with feathers on them that are early tyrannosaurs, at least until the early Cretaceous.

• 1:21:50Speaker 01

  But yeah, they're knocking around as relatively small animals in Europe and Asia. We have a couple from the UK. We have a whole bunch from China, there's stuff from like Kriegerstan and places like this. I think there's one relatively early one from Russia.

• 1:22:03Speaker 01

  And then when they get into the early Cretaceous, they start getting quite a bit bigger. So something like eutyrannus, if you wanna, there you go. So eutyrannus is fuzzy. We have three specimens definitively feathered. It gets to six, seven meters long.

• 1:22:21Lex Fridman?

  There's some funny looking about the sexy, smaller, earlier version of the T-Rex.

• 1:22:25Speaker 01

  But, but again, this is seven, eight meters, maybe weighs half a ton or a ton. Like, we, we are very much on the menu for an animal that size and it's massive and dangerous. Quite what triggered them, there's general patterns in evolution of size change and one famous one called Cope's Rule, I've worked on a fair bit. She's the idea that over time, things tend to get bigger and they do for various different reasons. One of which is just pure, almost like diffusion. If you start small and you evolve. Well, you can't get much smaller, but you can always get bigger. So you, you're naturally kind of diffuse away. Whereas if you're a blue whale, you probably can't get much bigger and its descendants will probably end up being smaller.

• 1:23:04Speaker 01

  But there are reasons that bigger things do better. You can hunt more stuff, you're more energy efficient, you can move more efficiently. You're dominant in contests, particularly with con specifics. If you're trying to win a territory or win mating rights. Bigger things usually beat up smaller things. So there's going to be selection favoring them. But then big things don't usually do well in extinction events. So that tends to reset the clock by killing off the big stuff and then smaller stuff does better.

• 1:23:31Lex Fridman?

  So mostly there's evolutionary advantages.

• 1:23:33Speaker 01

  But, but a fairly big one. So yeah, it's the, it's the classic thing of there's a day to day advantage of being bigger. And that might last for a few million years, right up to the point that suddenly there's the biggest drought the earth has encountered in five million years. And then all the big stuff just gets nailed.

• 1:23:49Lex Fridman?

  Also, we should probably say, is this accurate to say that the bigger you get, the fewer of you.

• 1:23:54Speaker 01

  There are, yeah, there's, there's just less fundamental space, you know, there's more mice than there are elephants. There are more elephants than there are whales, like there is only so much biomass that an ecosystem can support.

• 1:24:07Lex Fridman?

  And bigger things are just worse at repopulating in extinct events, for example.

• 1:24:12Speaker 01

  Right, so that, so they're less likely to survive because they need more fuel. You know, what would feed a mouse for a year won't feed an elephant for a week. So if, and, and of course, the mice are going to have an easier time finding a few little seeds than elephants going to find tons of food. And then they've got less genetic diversity. There might be 5,000 mice, there might be 200 elephants. So who's likely to have more genes or who's likely to have selection acting on those genes to produce a survivor? Well, the one with five or 10 or a thousand times the population. And then, yeah, on top of that, you've then got the very slow reproductive cycle, which then, again, gives evolution not a lot to work with. If, as an elephant, you're breeding once every five years and as a mouse, you're doing it once every eight weeks.

• 1:24:56Lex Fridman?

  What can we say about the, the evolution of just the, the massive bone crushing power of?

• 1:25:02Speaker 01

  So, so that starts kicking in seriously, kind of eutyrannosizing up. So that's when you start getting the not just bigger animals that are getting to a comparable size to the other big dinosaur carnivores of the time. You start getting those bigger heads. But even then, relatively late in tyrannosaur evolution, so getting into kind of the middle part of the late Cretaceous. You, you see a split and we have a group called the aeliorhominids, um, which have really, really long, thin skulls. And they look much more like a kind of, is a velociraptor. They look much more like a giant velociraptor-ish than a tyrannosaur, still relatively small arms. Um, but it's, it's a very long snout.

• 1:25:45Speaker 01

  And so this is a fast biting animal with a relatively light bite. So it's probably taking really quite small stuff proportionally. And then the other side, you've got the tyrannosaurines, which are the really big headed ones. And so that is a few ancestral things like Albertosaurus and Gorgosaurus.

• 1:26:04Speaker 01

  From both from Alberta, but then Daspletosaurus, a thing I named called Ju Ching Tyrannus in China, and then Tarbosaurus and Tyrannosaurus. And you've really only got three or four of these ultra giants, which are all kind of 10 meters plus in size, and then have the really broad skull, the real kind of excessive bite force. But even things like Albertosaurus, which is, I mean, a big animal, seven, eight meters, a ton or so. They're not quite T. rex, but they're definitely more robust than the other contemporaneous carnivores. So there is this progression of getting bigger, getting a bigger head, the teeth get bigger, but there's fewer of them,

• 1:26:47Speaker 01

  building up the bone biting and the and the power. But with some interesting evolutionary off branches in the way that, yeah, cats are largely much of a muchness, but then you get things like bobcats and lynx, which are actually quite bulky, stocky little cats that don't have the long tail and are doing something quite different.

• 1:27:06Lex Fridman?

  Can you just speak almost more generally because T. rex is sort of one of the great apex predators of history of Earth. How does a apex predator evolve? Like, why did T. rex win? Why isn't everybody, why isn't there like a vicious race to the top?

• 1:27:22Speaker 01

  I have a, I have a problem with the term apex predator because

• 1:27:28Speaker 01

  ecologically apex predators are generally defined as things that eat other predators. So a great white shark is because it's eating stuff like tuna and sea lions, which are themselves predators. So it's a predator of predators, whereas people, people love saying lions are apex predators and they love saying T. rex is an apex predator. They're eating herbivores. This is not some, this is not some weird and unusual thing. They're the largest predator in their ecosystem, and they are a giant one. My friend Darren Nash has moved to using the word arch predator. So it's like some kind of. Massive thing, but avoiding the term apex, because I think that leads into a it's it's it's a subtle terminology thing, but like.

• 1:28:13Lex Fridman?

  Uh, an important one. I just learned something today, so I didn't understand. I thought I was I was using the the word apex predator as.

• 1:28:20Speaker 01

  But that's because everyone keeps using it when I don't think they should. And and now you're getting into linguistics. It's like, well, if everyone uses it to mean that, does it now mean that rather than what it should mean? And then I'm probably losing that argument, because actually you'll probably find way more stuff calling it an apex predator than you will an arch predator. But but here we are.

• 1:28:37Lex Fridman?

  Arch predator, beautiful. I I I learned something today, but that would that you're saying T-Rex didn't eat other predators?

• 1:28:43Speaker 01

  Well, it's it's probably not going to. So we can get into, though I'd prefer not to because it's tedious, the argument of whether or not there's these small things, which some people have said is a different group called nano tyrannus, or a different species called nano tyrannus. But fundamentally, T-Rex is definitely weird, even compared to all the other giant tyrannosaurs that are very closely related to it. Because it is by far, ludicrously by far, the largest carnivore in its ecosystem. So.

• 1:29:14Lex Fridman?

  So it doesn't really have competition, actually.

• 1:29:16Speaker 01

  I mean, so so this is a velociraptor skull. Um, there are there are there are some carnivores that are a bit bigger than this.

• 1:29:23Lex Fridman?

  Yeah.

• 1:29:23Speaker 01

  But not enormously so, um, which we're knocking around is T-Rex. The the skull's the same time tooth crack. Right. But but like, you think about that, and that's like going, go that's like going to Africa and going, okay, there are lions. What's the next biggest predator? And it's like, well, there's a weasel about this big.

• 1:29:45Lex Fridman?

  Yeah.

• 1:29:46Speaker 01

  Like, it it's that kind of size difference. And you don't get that normally in ecosystems.

• 1:29:52Lex Fridman?

  So it didn't have some of the other big dinosaurs around it?

• 1:29:55Speaker 01

  Not carnivores. There's huge herbivores, but there's no huge carnivores around.

• 1:30:00Lex Fridman?

  Oh, I see. It would it would eat those, the juvenile of the herbivores, but not.

• 1:30:03Speaker 01

  Oh, yeah, it's going to be eating triceratops and edmontosaurus and parasauralophus. There's even a couple of giant sauropods knocking around in some places. It's it's going to be hoovering them up. But like, how often is it going to eat? Again, velociraptor isn't there, but how often is it going to eat something the size of an adult velociraptor?

• 1:30:18Lex Fridman?

  Yeah.

• 1:30:18Speaker 01

  I mean, they're a fraction of our size and we're probably too small. Th- this is like lions hunting mice. Like, you're just not gonna bo- unless one like virtually runs into your mouth, you're not gonna go and try and eat it.

• 1:30:31Lex Fridman?

  So the question still stands about arch predators then, like, how does it, how do you win?

• 1:30:37Speaker 01

  Yeah, well, I mean, so, I mean, there's, there's no real winners, there's just, you know, turnover because ultimately the birds, you know, it, it's, it's still lost out when, when things went wrong. And as we were just talking about, you know, things do tend to lose out when they're big, they're just so much more vulnerable to extinction.

• 1:30:56Speaker 01

  But clearly dinosaurian ecosystems had much bigger herbivores and therefore by extent much bigger carnivores than any system we've seen before or after. Even in relatively sparse ones like spits of the late Triassic, when the dinosaurs were really just getting going, or the very early Jurassic. But you've still got some like multi-ton herbivores and then you've got some multiple hundred kilo predators. So about as big as elephants and lions get today. And then, once you're in the Jurassic and Cretaceous, it is entirely normal to have

• 1:31:35Speaker 01

  multiple species that are 10, 20, 30 tonnes plus as herbivores and anything up to five tonnes as a carnivore. I mean, T. rex is probably the biggest of them, but carnivores that exceed to fully terrestrial carnivores that exceed a ton. There's dozens of species of dinosaurs.

• 1:31:56Lex Fridman?

  Is it interesting to you that no other carnivore predator was able to develop in that environment over millions of years?

• 1:32:04Speaker 01

  I mean, they're probably just ecologically dominant in the way that mammals are now, you know. Crocs get bigger than lions and tigers, but they're fundamentally tied to the water. But you don't see crocs roaming Serengeti or anything like that. But yeah, big, I mean, the really big crocs even now get to over a ton. So those are very serious animals and I think big polar bears. Are in the like 500 kilo range, though again, they hunt a lot of stuff in water and then things like grizzlies or at least partially herbivorous or omnivorous.

• 1:32:37Lex Fridman?

  So there was a very large marine reptile, mosasaurus. Did T. rex ever come across that?

• 1:32:44Speaker 01

  In theory, at least, the really giant mosasaurus are much bigger in the same way that unsurprisingly whales are much bigger than terrestrial carnivores now. Jurassic Park unsurprisingly has rather exaggerated it. So the one from Jurassic World, it's like twice the size it should be. But some of these things were still like, you know, 15, 20 meters. But yeah, some of them are absolutely giant. We, we had one dug up in the UK just a couple of years ago and I got to see the skull of it or a cast of the skull. And yeah, it's about the same size as a T. rex skull.

• 1:33:16Lex Fridman?

  If we take a ridiculous detour before we get back to science.

• 1:33:21Lex Fridman?

  What creature in the history of Earth would challenge a T. rex in a fight, would you say?

• 1:33:25Speaker 01

  On, on land.

• 1:33:26Lex Fridman?

  On land.

• 1:33:27Speaker 01

  I mean, nothing reasonably.

• 1:33:30Speaker 01

  Like the, the, the really big ones are gonna be. The, the, the only other thing you can really add is the, I said, this might be a very British adage of it's not the size of the dog in the fight, it's the size of the fight in the dog. So yeah, maybe there's something a bit smaller, which is just hyper aggressive and that would be enough to win like the the classic honey badgers chasing off lions. It's not that a honey badger would win in a fight. But if the honey badger is prepared to put up that much of a fight and the lion really doesn't want to get hurt, then, then he kind of technically wins.

• 1:34:02Lex Fridman?

  You can't imagine like, like any of the cats can't like tigers and none of them can do, I mean, the size difference, the power, the jaw, all that kind of stuff.

• 1:34:10Speaker 01

  Yeah, but going to T. rex, like what could reasonably challenge it? There's a couple of other giant tyrannosaurs. There's a couple of giant caradontosaurus from South America that I'd say are comparable in linear measurements, but are probably rather smaller and rather lighter. In which case your money's going to be on the bigger guy with the bigger bite. And that simply is T. rex.

• 1:34:32Lex Fridman?

  And the bite is important.

• 1:34:34Speaker 01

  Yeah, I think it is because yeah, these, these guys. The caracarasaurus, they're much more cutting and they're really killing stuff, probably by grappling with the arms because they do have big muscular arms with big claws and then slashing away at stuff. So I think they're probably doing something more like, almost like wolves or hyena or hunting dog, where they're harrying stuff and slashing at it and you're basically bleeding them out and wearing them down.

• 1:35:04Lex Fridman?

  So what about that strategy? So maybe you could speak to biting strategy. So a T-Rex is, I guess, a relatively slow bite but extremely powerful. What about animals that have very fast bites?

• 1:35:17Speaker 01

  So it's very simple mechanics. You know, if you have a very long jaw, you're going to close faster, but with less power at the tip than if you have a really short one that's deep. And so that really is it. But yeah, let's say there's things like yamarramins and then there's things like, yeah, velociraptor and a lot of its relatives, really very, and not just small, but you know, narrow. It is narrow snouted. There's not going to be a lot of fundamental strength here. The teeth, very numerous, very small. So they're much more about grabbing something tiny, you know. Velociraptors eating rat-sized stuff, that's gonna be probably its primary diet.

• 1:35:55Lex Fridman?

  So I wonder if there's a bunch of smaller, fast-biting things that could just bleed a T-Rex to death?

• 1:36:01Speaker 01

  They're gonna struggle though. I remember doing some work for one documentary and they, they literally wanted velociraptor fighting a T-Rex. And so like, you do know this is like, we're gonna shoot some meerkats, killing a lion. And it's like, well, you can film it, but no one would believe it because, you know, these ankle-high things trying to like savage a shin bone. Oh, yeah, I'm sure they'll make some holes and it'll lose some blood and it may not be very happy, but it's, I don't think they're gonna win.

• 1:36:33Lex Fridman?

  The size of a velociraptor was exaggerated by Jurassic Park.

• 1:36:37Speaker 01

  Enormously. I mean, they get a bit bigger than this in terms of the skull. But yeah, they're kind of thigh-high. To me, like a meter or so to the top of the head, two meters long. Whereas in the movies, they're like standing taller than guys who are six foot. So it's just massively, massively scaled up. And then these kind of big, kind of domey heads, then they're not the really long, narrow snout.

• 1:37:03Lex Fridman?

  Maybe we could take that tangent. What does Jurassic Park and Jurassic World franchise get right and wrong?

• 1:37:08Speaker 01

  I mean, get wrong a hell of a lot.

• 1:37:09Lex Fridman?

  What, what are some of like really definitive things to you that are interesting that it gets wrong? And also, what are the things it, it gets pretty close to right?

• 1:37:18Speaker 01

  Um, I mean, I, I just want to press with my answer because I always, I always get asked about this understandably. And it's like, I, I get that it's a movie, but if someone's going to ask me, what does it get wrong? I'm going to give them an answer, but I get people going, oh, you're just nitpicking. Oh, you know, it's fiction. Oh, you know, it's made up. Yeah, I do know, but someone asked the question, so here's the answer.

• 1:37:37Lex Fridman?

  I should say that some of the things I've heard you describe, I feel like it's the responsibility of those folks to get it right. I, I think there, there's, there's something, um, I really deeply admire. There's a show called Chernobyl.

• 1:37:52Speaker 01

  Hmm.

• 1:37:52Lex Fridman?

  It's like, they don't need to be that accurate, but they really, it's like the detail of the, the kitchenware.

• 1:38:01Speaker 01

  Yeah.

• 1:38:02Lex Fridman?

  In a room, like just to get the tiniest detail right. Who's that for? I don't know who's that for, but that's for the, that's great art. That's for the, that's the spirit of the thing. And like that, if you focus on getting those tiny details right, there's some magical thing happens about the bigger story.

• 1:38:21Speaker 01

  Yeah.

• 1:38:22Lex Fridman?

  If you don't care about the details, the story gets corrupted. So I, I just want to say that some of the things you describe, like how many fingers.

• 1:38:31Speaker 01

  Yeah, yeah.

• 1:38:31Lex Fridman?

  It's like, that's important to get that right. Cause if you do, some magical stuff can really emerge and it, it could become a legendary film as opposed to just the.

• 1:38:38Speaker 01

  Yeah, I mean, that, that's my take. Again, I, you know, I, I've worked on documentaries where they're claiming that accuracy is absolutely critical and a hundred percent important. And they won't put anything on screen that I haven't told them to. And then many of those things turn out not to be quite as true as advertised once you get around to it. So I'm, I'm aware that when even documentaries will take massive liberties, you can't be too harsh on what is popular fiction. On the other hand, I am also aware that it is. By far, by a ludicrous degree, the most popular bit of any kind of media that includes

• 1:39:20Speaker 01

  my work, as it were, or something that I'm actively engaged in and know about. And so whether or not it should have that influence, or whether or not the filmmakers should have responsibility, it does, it does have that knock on. So, I mean, it's simple as stuff as, tyrants can't see if you can't move. Yeah, it could. I don't know where that came from. As far as I can tell, Crichton just dreamed it up. In, in The Lost World, his sequel book, he hints that there's a research paper that says it, and that's kind of where he got it from. There's a second paleontologist character who's advising Dodson, the evil InGen guy. And he says, oh, no, that's from such and such's research. And like, I tried looking up, as far as I can tell, it doesn't exist and never did. So I think it's just straight fiction.

• 1:40:04Speaker 01

  And it's like, it works for the, it works for the book and it works for the movie, but it's, as far as I can tell, it's straight fiction and Crichton just made it up. If it's buried in some bit of literature, he's done better finding it than I have. And I've had a really good look and I know how to look. And I've never come across anyone who's found it either.

• 1:40:22Speaker 01

  But it does, it just like warps the perception, you know? Velociraptor, cheetah speed, pack hunters, super intelligent, giant sized animals. And, okay, 1993, it's a bit more forgivable, but even then we were pretty confident they had feathers. Is any of that true? Wait, so, oh. Probably not. The, the, the pack hunter aspect? Um, so that's something I've written quite a lot about.

• 1:40:46Speaker 01

  The evidence for pack hunting in any dinosaur at all is almost non-existent. It, it basically doesn't exist. And that's going exactly back to, again, that stuff we're talking about bite marks and tophonomy and like the history of specimens and how you interpret. What kind of evidence would show like maybe bite marks from multiple sources? So it's, so it's really, really tough. So the, the main one which was put forward is there's this famous association in Montana of Deinonychus, which is often confused with velociraptor, including in the books and Foo Fighters, basically a bigger version of this that's rather older from the early Cretaceous.

• 1:41:28Speaker 01

  And I think called Tenontosaurus, which is kind of iguanodontine, so iguanodon, spiky thumbs, basically otherwise a fairly run of the mill herbivore. And there are two sites, I believe, for this, but there's one that's much more important, where you have a Tyrannosaurus carcass with Deinonychus carcasses. And so the interpretation of this is, well, this is a group that brought down the herbivore. And of course, the immediate kind of counter argument to that is, well, why did they all die there? Like, when, you know, when lions kill a wildebeest, they eat it, they don't all just die next to it. Yeah. Or even if they did kill it and start eating it, and then like, if they got into a fight and killed each other,

• 1:42:10Speaker 01

  well, lions as a species are not going to hang around for very long if every time they kill something, they get into a mortal fight and kill half the pride. Um, there's nothing obvious that killed them. Um, but it's at least possible that this was something like a predator trap. So predator traps are really neat. So La Brea tar pits is a classic example. The idea is a herbivore stumbles into something like tar. You've got your deer or wildebeest or mammoth or whatever it is, waist deep in tar and going, hmm, I'm dying, I'm dying, I'm making horrible noises. And, you know, Smelodon walks over and goes, great, and wades out after it. And he's now stuck. And then the next one, and the next one, and the next one, and the next one.

• 1:42:53Speaker 01

  And then low and behold, you now have something like La Brea, where they've got like, the, the numbers are something absurd, like, I think they've got like three mammoths and one ground sloth. And then it's like a hundred dire wolves and 40 Smelodon, because it's just sucking the carnivores in. Wow. And you get these really distorted ratios. I don't think that's the case of the Deinonychus Tyrannosaurus stuff, because there's ways that you can probably rule that out. But there are probably places like this where it's happened. Again, the other one is, um, the toxin one who's near Cleveland Lloyd. So she's coming up on your screen. That's another one, uh, with loads of dinosaurs, Allosaurus. Um, but we've definitely seen it with, I think it, I think this has come up with something like lions or wolves.

• 1:43:38Speaker 01

  Like, they found loads of them dead, uh, by a lake, and it turned out, oh, this pond. And this pond had got some really sort of nasty algal bloom toxin in it. And the interpretation was the same kind of thing, is that a couple of deer were drinking. This stuff's toxic and kills you within minutes, keels over, dies. Wolf smells dead meat, comes over, starts eating it, has a drink, keels over and dies. And then it's, so it's not getting, you're just dying from the toxicity rather than being like. Physically sucked in and trapped, but the same effect can happen. And so you just end up with a pile of dead bodies.

• 1:44:12Lex Fridman?

  So I'm pulling up some stuff here. First of all, shout out to perplexity. Super awesome. There it'd be great if you fact checked some of this stuff. So fossil discoveries, including parallel trackways and bone beds containing multiple tyrannosaurs, suggests these large predators sometimes moved and possibly hunted in groups. You as a person who wrote a book about the behavior of dinosaurs?

• 1:44:34Speaker 01

  Yep, let me deconstruct that like almost instantly. So it's because it's really easy because this this is my my book on dinosaur behavior. This is just the kind of thing I'm talking about. So the the tyrannosaur trackways of a group of tyrannosaurs is, I think, four or five tracks total. So it's like two from one animal, two from a second animal and one from a third animal. That's not the end of the world. That's somehow how trackways formed like, you know, the rocks broken up. They stood on mud and then they didn't, whatever.

• 1:45:03Lex Fridman?

  Just to clarify, trackway means footprints of multiple, maybe steps?

• 1:45:08Speaker 01

  Yeah, one of them has gone left and right and the other two don't. It's it's very fragmentary, but I haven't that that's not a problem with the interpretation. The problem is this is interpreted as a group of them moving together. Well, why? Because they're going in roughly the same direction. Okay, and they're roughly equal sizes. Okay, but like I've seen solitary animals moving in groups. A guy I know quite well in South Africa, I go to South Africa regularly for my teaching, actually. And he's one of the big guys at South African national parks and he gives me the skinny on all kinds of weird stuff. And he's telling me a few years ago that one of his park rangers had observed leopards hunting together in a group.

• 1:45:51Speaker 01

  Now leopards are basically not just solitary, they're like antisocial. They beat the hell out of each other if they come near each other. But I've also seen, you know, you you get game trails are a thing, paths that single animals take. If a female is in heat, like males will track her down and follow her. So you'll get one set of footprints and then a couple of hours later, a male will come past and a couple of hours later, another male will come past. And now you've got three sets of footprints all travelling in the same direction on the same bit of path, but they live on their own, let alone hunting together, which is a massive step above this. And then the one I've talked about quite a bit in my book is Spotted Hyena, Cracuta

• 1:46:35Speaker 01

  Cracuta, which is the one, there's a whole bunch of hyenas, but this is the one everyone knows, they're the big laughing hyena. And can see plenty of Attenborough-type documentaries of them, seven or eight of them, or even 10 or 12 of them going into a herd and ripping apart wildebeest or zebra, whatever it is. But actually, if you read the scientific literature, this is really rare. They mostly hunt on their own. Now, they do live in these social clans with hierarchies and complex social interactions. They are very social animals, but they mostly hunt on their own.

• 1:47:07Speaker 01

  So even if you find loads of trackways of them moving together, or as, again, there's one, if not two, for tyrannosaurs, we've got multiple tyrannosaurs together, and that's been argued for pack hunting. At best, that argues they might have lived together, but it doesn't tell you whether or not they hunted together. So how can we make a decision on one way or the other? So, I mean, I, I tend to be ultra-conservative in this context, and I think we should probably avoid saying things that we're not quite confident about. I, I don't want to ever go down the, we must have really definitive 100% convincing evidence because this is paleo, we don't have that kind of data.

• 1:47:47Speaker 01

  But just as I talked about with things like the predator-prey size ratio stuff, there is data we can start to use on living species about what tends to trigger hunting in groups or living in groups and what data there might be from stuff like brain sizes or other trackways. Or again, we do have bite marks indicating prey size. If you start finding repeated attacks on big prey from relatively small predators, that would be quite convincing. As you said, maybe we had bite marks of multiple different sizes. Now, that on its own, it comes hard because obviously scavenging, you know, tyrannosaurs are an exception.

• 1:48:30Speaker 01

  Most dinosaurs, most carnivorous dinosaurs have pretty similarly shaped teeth. So how easy is it to tell? An adult from a juvenile from an adult from a different species that's just a bit smaller. Probably pretty tricky. I mean, for me, I think the the kind of gold standard, which I don't think we're ever going to find, but you never know. Like you could in theory get a trackway of something like a herbivore. With a whole bunch of carnivore tracks coming by. We do have a couple like this, but they don't have what I'd really want to see, which is if you trace the footprints of the individual carnivores. And if A's in early on, A's footprint go on top of B's. But later on, B's go on top of A's.

• 1:49:15Speaker 01

  They must have been there at the same time. Cause there's no way they could have been even minutes or hours apart. So if you had that, then those two must be together, or at least within sight of each other. And one's not turning around and roaring or having a fight. If you can do that with seven or eight, all converging on one herbivore. And then everything goes manic. Well, that's really pretty convincing.

• 1:49:40Lex Fridman?

  It is so fascinating and awesome. But like the Sherlock Holmes aspect of paleontology, like figuring out, because you have very little signal.

• 1:49:48Speaker 01

  Yeah.

• 1:49:48Lex Fridman?

  And you have to figure out the puzzle of it from that. And like, that's, this is just a brilliant, you're giving so many brilliant examples of like, yeah, if A steps on top of B and then B steps on top of A, that's a strong signal that they were walking together.

• 1:50:00Speaker 01

  I am a bit of a Sherlock Holmes fan. And he references Cuvier. So Cuvier is this legendary French anatomist, Baron Cuvier. He was the first guy to posit that things went extinct, working on mammoths. And he said, but there's nothing like this alive today. So extinction happens, which before that we didn't really know. And Holmes has a line about just as Cuvier can restore an animal from the smallest bone, so I can restore the events from the smallest detail, or I'm paraphrasing, but I'm not far off.

• 1:50:31Lex Fridman?

  Yeah, there's truth to that.

• 1:50:32Speaker 01

  You have. Used an analogy that Conan Doyle specifically used for Holmes, going back to paleontology.

• 1:50:39Lex Fridman?

  I mean, it's obvious. It's clear. It's right there. Yeah.

• 1:50:41Speaker 01

  That that's how on the nose you are with that one.

• 1:50:44Lex Fridman?

  So, okay, so basically you clarified and showed all the things in Jurassic.

• 1:50:48Speaker 01

  Yeah, we we yeah, we we got off topic before we even got onto Jurassic, but.

• 1:50:52Lex Fridman?

  And just for velociraptor, you said that, you know, yeah, the size, the pack hunting, all of that.

• 1:50:57Speaker 01

  The pack hunting, just to round off on that, like, I don't know. Maybe, um, there's actually been some more recent stuff on Deinonychus, looking at things like isotopes in the teeth and feeding traces and some other stuff. It's hinting that maybe there is more going on there. Um, which is great. I'm I'm not anti the idea that this exists, but you you absolutely get this buildup of the idea that velociraptor is a pack hunter comes from Deinonychus. And I think the evidence from Deinonychus is really weak in exactly the way that, okay, lions are group hunters. We know they are. Does that mean that leopards are? And tigers and puma? No. So why on earth do you think that just because, even if Deinonychus is,

• 1:51:40Speaker 01

  that doesn't really tell you anything about velociraptor? Um, group hunting has all kinds of more complicated dynamics going on it than just close relatives tend to do it. You can flip that around, you know, African hunting dog, wolves, um, things like bush dogs, there's various canids that all hunt in groups. But then you've got things like mane wolves, which are effectively solitary. Um, the hyenas, spotted hyena, oh, yeah, these super social animals. But the brown hyena, the striped hyena and the odd wolf are solitary. So you you just can't do group versus solitary of close relatives or anything like that. I am very sure a ton of dinosaurs were

• 1:52:23Speaker 01

  aggregates, lived lived in groups to some degree. And I'm very sure some of them were social with complex lives and hierarchies and even pack hunting. Which ones?

• 1:52:34Speaker 01

  I have very little idea because I think the data is so sparse that we can't really say it with any confidence for anything, in my opinion. I think that can be got at. I think we need to start getting at it with the sort of stuff I'm talking about, like get a better understanding of what drives sociality in lions versus tigers versus leopards, you know, relatively close relatives who overlap, don't forget in India, leopards and tigers overlap with lions, the Asiatic lion is still there. So you can talk about ecosystem structure and prey size and prey type and all this stuff. We can, maybe, maybe we can start piecing that together a bit better and then apply that to stuff like the trackways

• 1:53:17Speaker 01

  and the isotopes and all the rest of it, bite marks and these mass mortality sites. So I think it can be done, but personally, like what were pack hunters? No idea. I don't think, I don't think any of them were in the sense that I don't think we've got good evidence for any of them.

• 1:53:32Lex Fridman?

  But there probably exists on earth definitive evidence, one way or the other.

• 1:53:38Speaker 01

  Yeah, probably for some of them. I mean, I think it's well within their scope. One of the papers writing about this, ironically arguing against pack hunting in Deinonychus, said that, well, it's probably not the case because you don't really see pack hunting in birds. And so if you don't see it in birds, then dinosaurs being their ancestor, or if birds can't evolve it, then maybe dinosaurs couldn't have evolved it, which I'm not sure is a great logical argument because of the complexities of social behaviour anyway. But then there are a couple of birds which actively hunt in groups, things like the giant ground hornbills, Ethiopia and South Africa are a really good example of that. So, so that point is incorrect. And then we see, if not true sociality, we see cooperation

• 1:54:23Speaker 01

  in crocodilians and we're seeing degrees of social behaviour in things like iguanas. So the idea that like, well, birds are super advanced and dinosaurs can't do it because the stupid reptiles are too stupid and therefore dinosaurs are more like them, which isn't quite what they're saying, but it's sort of the unwritten idea, well, we have social behaviour and cooperation behaviour incorrect. Rocks and in lizards. So that really gives you the impression that dinosaurs theoretically at least are perfectly capable of that.

• 1:54:52Lex Fridman?

  So there's pack hunting, but there's also sociality, which is such an interesting idea. How did they live? And this is something you look at that paleontology doesn't often touch is like the lives.

• 1:55:05Speaker 01

  Yeah, because, because, you know, animals are doing complicated things. So, you know, in the case of lions, a large part of this is down to territoriality and the the males ultimately are defending the territory and that's effectively protecting the females. But of course, what they're mostly protecting them from is other males. So there's a ludicrous bit of self-interest. But that's effectively how it's operating as a system. But it could just be predatory type cheetahs are my go to example for this. So cheetahs are the weird ones. Compared to the other cats, because females are solitary, but males are social. So brothers will, when, when, you know, if the female has five or six cubs, the brothers will stay together in a group and then the girls will go off on their own.

• 1:55:47Speaker 01

  And if you're, if you're the only brother or the only survivor, you were usually hung up, hook up with a gang of other males. So cheetahs are pack hunters if you're male and a solitary hunter if you're female. So it's not about territory, defence or occupation for them. It's about prey type.

• 1:56:03Lex Fridman?

  Is it possible to know the sex of a T. rex or any of the other dinosaurs? Like what, what can paleontology show us?

• 1:56:10Speaker 01

  So in theory, yes, in practice, it's way more complicated. So unless you get very lucky, we have a handful of specimens that still have eggs inside them, instant giveaway. But that's like two or three.

• 1:56:24Speaker 01

  What you can look for is both reptiles and birds have a thing called medullary bone. And when you're laying eggs and you need a lot of calcium very quickly, because the, the egg shell goes on basically like, kind of like the last minute during egg development. So you need a lot of calcium very quickly. So during the laying season, these animals grow this really weird kind of bone texture on big things like the femur and the humerus, like really big bones in the body. And that's, it's got a weird texture because it's full of blood vessels and it's full of blood vessels so that you can basically apply a lot of blood supply to it quickly, suck up some of the calcium from that bone, take it through the system, put it on the eggs,

• 1:57:04Speaker 01

  lay your eggs. We can find that. So if you have a dinosaur bone and it's the right kind of thing, so you can't do it on like a finger or a claw or a bit of rib, but nice big bone, you could cut a chunk of that out, grind it down to the point that it's virtually transparent, fraction of a millimetre thick, put it under a microscope and have a look. And if you see the right bone texture, that's, there, there's some exceptions, but that's very probably medullary bone and you have yourself a female. So the instant assumption is, okay, so you can tell female from male. No, we can tell laying female from everything else. So males won't have medullary bone. Young females won't have them. Females outside of the breeding season

• 1:57:46Speaker 01

  won't have it. Females inside the breeding season, but maybe they've been really sick this year, don't have it, or they laid their eggs early and now they don't need it anymore, won't have it. So occasionally, if you cut up a bone, which of course we try not to do that much, you can get the signal of medullary bone and infer that you have a female in the breeding season. But there's no like large bone structure differences. Well, maybe there is, but we haven't seen it. You look at things like, um, koodoo or, um, black buck and all kinds of antelope or even most deer. And the males have horns or antlers and the females don't. And then you look at something like triceratops and all

• 1:58:30Speaker 01

  the ceratopsins, it's a big clade of, oh, must be 40 species by now. And every single one of them has the frill and has some kind of horn somewhere. You don't have the hornless ones or the frillless ones in the way that we do with. A lot of these.

• 1:58:49Lex Fridman?

  I'm trying to figure out, is there, how many of the species is it obvious that there's like, like pelvis differences, all that kind of stuff?

• 1:58:57Speaker 01

  So pelvis differences works on like humans and apes and maybe a couple of other mammals, but it's mostly not very good because we, it's because we give birth to such a gigantic baby with a gigantic head compared to our sizes, that women have different pelvises to men.

• 1:59:12Lex Fridman?

  And then there's size differences, like the skull is not as reliable to the pelvis.

• 1:59:16Speaker 01

  And then, again, you just need to look at, you know, humans are always slightly dodgy with this because of, you know, our evolutionary history and cultural history, but like, you know, there's, there's population differences, you know, you, you, there are, there are main female lions in places, there are mainless male lions in places. Reindeer, female reindeer have antlers in winter. So Rudolph was a girl because every illustration of Santa and his reindeer ever, they all have antlers and that's, that's a female reindeer, not a male if it's winter.

• 1:59:47Lex Fridman?

  So basically, we don't know much about the dating and the sex lives of T. rexes.

• 1:59:52Speaker 01

  Well, not much, but you can make some inferences. So for example, all tyrannosaurs have at least some kind of crest on the head. The early ones have like this midline crest, it really doesn't work on a human. They have like a midline crest running along the top of the nose that sticks up. The later ones largely don't, but they do have this weird armored structure along those fused nasals and then they have little horns over the eyes. Those, as far as we can tell, don't really have any kind of obvious mechanical function and loads, like outside of the feathered dinosaurs, the vast majority of dinos, of carnivorous dinosaurs have some kind of crest or display feature on the head.

• 2:00:35Lex Fridman?

  When you say display feature, meaning for sex appeal, to attract mates?

• 2:00:38Speaker 01

  Or something like that. So I, I've always favored the term socio-sexual selection to cover both sexual display and sexual dominance and communication, but also social ones because those two things are hard to tell apart. Female lions find males with darker manes sexier, but male lions find males with darker manes more intimidating. So one of them is sex, but one of them is social.

• 2:01:04Lex Fridman?

  Nice. I mean, I guess it goes hand in hand. Sure.

• 2:01:08Speaker 01

  It can, but then you get things like the other one I go for is black swans, these beautiful Australian birds. They have these really weird curly feathers on their wings and males and females both have them. And males prefer females with curlier feathers and females prefer males with curlier feathers. There's an obvious sexual link, but then females fight too. Females fight over the best nesting spots and the females with the curliest feathers tend to win those fights.

• 2:01:35Lex Fridman?

  How does that make sense?

• 2:01:36Speaker 01

  This gets into classic sexual selection theory. It's what's called an honest signal. You couldn't have those curly feathers if you weren't able to support them. Because they're their primary feathers on the wings. And what it actually does is it makes it harder to fly. So you're basically going, look how tough I am. I've grown this big and I can fly and carry on with my giant curly feathers. Because I'm really tough and I'm in good shape. And it's the same with the lion. The reason you get pale lions in the south is because it's close to the equator because it's too hot. So there's the trade off because if you have a really black mane, yeah, all the males know you're rock and all the females know you're super sexy, but you just die of overheating.

• 2:02:21Speaker 01

  The trade off is if the heat's gonna kill you, you're probably better off being a bit paler and surviving in order to reproduce than you are being jet black or just dying instantly as soon as it gets hot.

• 2:02:35Lex Fridman?

  So there's trade offs there. Okay.

• 2:02:36Speaker 01

  Yeah. And that's probably what's happening with the theropods. The all the little crests and horns, ceratosaurus, dilophosaurus, tyrannosaurs, allosaurs have big crests over the eyes and all kinds of others. My, I've written about this. I think this is the trade off. You're going for the sexiest look and the sexiest look is the biggest horns or the biggest spikes and whatever's on the head. Probably also then with the brightest colors and the most display patterns. But also, this this gives you away to your prey. If you're trying to hide or you're trying to sneak up on something, being brightly coloured or having stripes or all this extra stuff on your head, you you you get spotted. But then that's the trade off is if I'm this

• 2:03:19Speaker 01

  big and my horns are if my horns are this big and this red and yellow and I can still, whoop, I can still run those guys down and hunt them and kill them and eat them.

• 2:03:29Lex Fridman?

  Yeah.

• 2:03:30Speaker 01

  Then look how great I must be. Whereas that little guy, he's only got weedy little crests and they're and they're really dark because he's so bad at catching stuff, he doesn't have the extra energy to grow big crests. And so that's why. But when you're a herbivore, you don't have that pressure, particularly something like, this is Predaceratops, but something like Triceratops and these guys, they're living in big groups. You can't hide from a predator when you're a group of 20 animals that are 10 tonnes each. So who cares? You just grow the biggest signal you can possibly grow. And lo and behold, they have giant frills and giant horns.

• 2:04:06Lex Fridman?

  What can you say about beauty in evolution? So something that's maybe can educate me, but something that's not quite an honest signal, that's just pure beauty, like peacock feathers.

• 2:04:18Speaker 01

  So there are things which we think operate closer to that. So there are, these are the two kind of classic ideas of sexual selection, and both are probably true to certain degrees in various different species. One is the honest signal, or the it's the kind of handicap hypothesis, because you're holding yourself back whilst proving you can still do it. I ran the marathon, you know, carrying a couple of weights, you're obviously stronger than the guy who ran the marathon without. And so that's why it's an honest signal, and it's why it's a handicap. But the other one is what's called the sexy sons hypothesis. And the idea is a female might just find a male attractive for no other reason than random. There is. Some component of her brain or whatever it may be that that just looks cool.

• 2:05:03Speaker 01

  And you can actually sort of get this as a human, like, forget, forget human beauty. You could, you can look at a bottle and go, that bottle's kind of nice and that bottle's kind of ugly.

• 2:05:12Lex Fridman?

  Where do you put like, like birds are interesting with this. Well, where do you put peacock feathers?

• 2:05:17Speaker 01

  So they're, they're probably more handicap hypothesis because the colors that go into them and the sheer size and shape.

• 2:05:24Lex Fridman?

  I see.

• 2:05:24Speaker 01

  And these things basically can't fly. Um, they're really vulnerable to predators.

• 2:05:29Lex Fridman?

  Can the handicap hypothesis explain just how beautiful peacock feathers get? Cause they go.

• 2:05:35Speaker 01

  So probably not entirely. There's, there's almost certainly randomness going on in there as well. And then the eye spots, we know that eye spots are attractive, are probably encoded in some way. Um, but yeah, so going back to the sexy sons, the idea is females prefer something different for whatever reason. And there might actually be some reasons females prefer things that are different. Different usually means separate and outside. And that usually comes with it, variation, like inherently.

• 2:06:04Lex Fridman?

  Also, variation is evolutionary a turn on.

• 2:06:07Speaker 01

  Yeah, basically.

• 2:06:09Lex Fridman?

  Wouldn't that, man, you're rolling the dice though, aren't you?

• 2:06:12Speaker 01

  Yeah, well, you, bro, right. So, so you, you've, you've got to remember again, it's really easy to look at that sort of thing with a human perspective. Where a maximum reproductive output, I think the, the record, there's, there's some obscure record, it's something like sixty six children, which is probably apocryphal. For a Russian woman who had loads of triplets and quads. But like, humans don't have many offspring, but most animals lay dozens of eggs or hundreds of eggs or thousands of eggs at a time. So actually.

• 2:06:44Lex Fridman?

  So diversity pays off more there.

• 2:06:46Speaker 01

  So diversity can pay off. We, we think that's probably a major part of the reason that sex evolved in the first place. Is it gives you resistance to changing environment and it gives you resistance to parasites and diseases, which often reproduce way faster than you do. You know, bacteria can divide in a few hours. We reproduce every twenty years. That's quite a difference. If we were all asexual clones and you're vulnerable to some disease, you're probably going to get wiped out. Look at the, you know, Irish potato famine or something like that. So different may be appealing simply because it is different. It's giving you variation. Um. And there is at least some evidence for that. There's um sword tails. So anyone who

• 2:07:28Speaker 01

  keeps little fish, uh if anyone who's a tropical fish uh keeper, uh sword tails are really quite common little tropical fish that you can get in all kinds of aquarium shops and they're a very boring fish shape, but the lower lobe of their tail has a big spike on it and that's the name. And they're really close relatives of a group called the mollies, which basically don't have that. And in the wild, there is these Amazonian fish, they don't usually encounter each other. But even if you go and get not even the domesticated form, because these things have been bred for, you know, decades at this point, you can go and get some wild mollies and give them a wild male sword tail and they think he's so much better than all the male mollies. They will go for that one and they will preferentially mate with that one. We

• 2:08:10Speaker 01

  don't know the exact mechanism, but it appears to be, it looks similar enough that I recognize it as a potential mate, but different enough that this is exciting. And then this is where the sexy sons kick in because the females are now, assuming those animals are successful and they can hybridize, or maybe it's just a male who just happens to be a little bit blue or a little bit redder or whatever it may be. Um, well, the female offspring, the daughters are probably going to inherit mother's preference. I really like red and the males are probably going to have red in them because their dad had more red. So guess what the next generation does? It's more red and the females like more red and you don't have

• 2:08:51Speaker 01

  to come back much further and suddenly all the males are bright red. And that's closer to beauty than I think almost anything else would be with still a naturalistic explanation.

• 2:09:03Lex Fridman?

  We kind of start talking about beauty from how much uh social life.

• 2:09:07Speaker 01

  Yeah, a T-Rex might have.

• 2:09:08Lex Fridman?

  A T-Rex might have. So uh, uh, just to kind of take that to a place of what we know and what we don't know. So can we kind of know something about their uh, their social life, where they lived, how they lived?

• 2:09:22Speaker 01

  So the very fact that they have these apparently socio sexually selected signals, the little crest and stuff in the head. So there's a branch of sexual selection called mutual sexual selection and the black swans are an advanced example of this. The classic sexual selection is yeah, your peacocks and your lions and things like this. Males are bigger and more flamboyant and whatever it is and they're doing all the competing. But you have mutual sexual selection and this is really common in a whole bunch of things that people are familiar with but don't know. Loads of seabirds, starlings, the common starling that we have in Europe and has been introduced into the US, parrots, various other things where basically males

• 2:10:04Speaker 01

  and females invest similarly in rearing the offspring. And so the idea generally, both with handicap and sexy son, but particularly with handicap, is the idea is the males are proving their worth. They're basically saying, I'm the biggest, strongest, healthiest, I've got the best genes, I should be the father of your offspring. They go around showing off and then mate with as many females as possible, while the females then do all the work and make the nest and look after the chicks and yeah, or rear them or give birth or whatever it may be, yada, yada, yada. And so the idea with mutual sexual selection is, well, what if there's not much food around? Things like puffins, penguins in the Arctic, where the male sits with the egg and the female toddles off, gets food and then comes

• 2:10:45Speaker 01

  back two months later or whatever it is. On their own, they can't rear the offspring. They have to have a male investment. Well, now, suddenly the male's now putting loads of effort in. So the male's now in the same position that a female would be in under the normal conditions. You don't want to be the sexiest, toughest, biggest male and you can only mate once. All right, there's various cheats, but we won't get into that just yet. You're only going to mate once and you're going to put all your effort into helping rearing offspring rather than chasing down as many girls as possible. Are you going to go for the biggest, fittest female as well? Or are you going to go for the small weedy one that doesn't look very well? You go for the best one. Well, how do you know that? Well, because she's got a crest as well.

• 2:11:31Speaker 01

  And so suddenly you now get mutual ornamentation, just like the black swans, where the males are checking out the curliest females and the females are checking out the curliest males. And you'll see they mutually pair up. This is what we see with things like starlings. Males like the brightest females, females like the brightest males, they tend to form pairs. The darkest and least bright ones are obviously kind of left with each other at the bottom of the pile. They tend to pair up, but it means that when you get signals in both males and females, like every triceratops or every tyrannosaurus, it at least hints that they're going down this route. And that they might cooperate for reproduction.

• 2:12:10Lex Fridman?

  Wow. Another like weak signal that tells a part of the story.

• 2:12:15Speaker 01

  And the problem is it's compromised by lots of things. So that goes back to your earlier question about telling males from females apart. The vast majority of dinosaur species, like 90 plus percent are known from a single specimen. And a specimen is not necessarily very complete at all. It might be a couple of bones. It might be one bone. It might be a tooth in a couple of cases. The actual number where we've got a decent number of real whole skeletons that we can actually compare to each other, less than 10, probably more like five or six.

• 2:12:47Lex Fridman?

  Can I ask you a weird question?

• 2:12:50Lex Fridman?

  If you were to, uh, let's say all humans died right now, you press a button, gone. How much of human civilization would you be able to reconstruct from just the skeletons that are in the ground? Like you just started collecting skeletons. There's a lot of them. There's, there's billions of them. Would you be able to start telling a story like urban centers?

• 2:13:13Speaker 01

  Yeah, probably.

• 2:13:14Lex Fridman?

  You'd probably reconstruct a lot, right?

• 2:13:16Speaker 01

  If, if nothing else, just the, you know, superlative brain cavity will tell you quite a lot, you know.

• 2:13:22Lex Fridman?

  Yeah, the intelligence.

• 2:13:23Speaker 01

  Must, must have been very, very smart with the brain that big.

• 2:13:27Lex Fridman?

  You can probably reconstruct some of the behavior, a lot of the behavior, social behavior, a lot of the stuff.

• 2:13:31Speaker 01

  You're going to see stuff like, you know, it's the famous one of, I think it was a Neanderthal. There was a famous question of like, you know, at what point do you think society exists? And it may have been one of the leakies, but the answer was basically that this skeleton, because it was someone with a real, like a properly busted leg. And then it fully healed. And it's like, if that person was on their own, just dead, someone had to look after them for months to get that level of healing. You only do that to someone you're really devoted to and probably a group of people because even one person can't look after one other person in. Right. So that's your society. And yeah, you think about the the pathology of skeletons in the human race.

• 2:14:15Speaker 01

  How, you know, how many of us have broken a bone? Most, most adults have probably broken a couple of bones, even if it's just a finger or or a nose or something. But then you think about what medicine has done and you would be able to see treatments of complete compound fractures of guys who survived horrific car crashes and treatments of cancer, bone cancers and stuff like that. You would see that. Well, how's that happening? Either they're magic or they've got some kind of, in which case they'd probably cure it instantly, or there's some kind of technology in society supporting that change.

• 2:14:50Lex Fridman?

  That just hints at the fact that the the evidence collection and the reasoning mechanism that paleontology and archaeology uses is really powerful.

• 2:14:59Speaker 01

  Yeah.

• 2:15:00Lex Fridman?

  And so it could, it could be very effective even even just with a small amount of data.

• 2:15:03Speaker 01

  I mean, but it, but it's the right amount of data. That's the thing. We can, we can find dozens of skeletons that we can't do very much with. And then the right one that, you know, things like stomach contents, you know, that's a super power or bite marks. It's a super powerful bit of data, but it doesn't turn up that often. So it's not like you can get it off every skeleton. And that's the thing. It's, it's the, it's the pool of data. And I think that's what people miss. We, we, as paleontologists, um, we get caught up on single superlative specimens and then try and take them as a like a silver bullet almost. So mycorrhaptor, I mentioned this before, little, little flying dinosaur crocile or gliding dinosaur crocile thing from China.

• 2:15:44Speaker 01

  We've got at least a dozen good specimens of it by now and multiple ones with stomach contents. There's one I've described with a little mammal foot inside it. There's one with a bird inside it. There's one with a lizard inside it. And there's one with a fish inside it. On their own, and this happened for at least two of the papers describing these things. It's like, it ate fish. These are fish eating animals. No, that one ate one fish once.

• 2:16:11Speaker 01

  That one ate one bird once, that one ate one mammal once, and that one ate one lizard once. So what have we actually got here? I suspect we've got a group of generalists, and we just happen to have found them eating different things at different times. But equally, it's also possible, at least, that, yeah, this is one of these things, and it had learnt to eat fish when the others hadn't. And actually, this was most of the fish eaters, and the others ate whatever they could get. Maybe one caught a bird up a tree in a nest, maybe one found it dead on the ground. You don't really know. What one of these things on its own is fascinating, but potentially misleading.

• 2:16:51Lex Fridman?

  The way you're describing it now, it seems like, yes, it's potentially misleading, but there's, in your whole way of being, and the way you've been talking about this stuff, I can see that it's not just the direct evidence you're mentioning. It's like, it's a bunch of intuitions you build up. It's like you're stitching together a bunch of little things. It's the Sherlock Holmes things. It's not just the clearly this one piece of evidence. It's like, okay, what do I know about the general other dinosaurs around the area, the different animals, how animals usually behave about this period, about the environment, and all of that comes together and then.

• 2:17:25Speaker 01

  Yeah, and that's, so one thing I've definitely written about is, yeah, the independent lines of evidence. Can you get stuff that is as far as possible, truly independent from the other data, and does it give you the same answer? And then when it does, that's incredibly powerful. So Spinosaurus, or the Spinosaurus as a whole, is my go-to example for this. So the guys, the famous big sail back and the weird crocodile-like head, though some of them look rather different to that. And if you look across all the species and specimens that we have, incredibly fragmentary and very badly known, but they're all basically

• 2:18:06Speaker 01

  associated with, when you look at the Gischtal, you see a whole bunch of stuff for these things. So they do have a surprisingly crocodile-like head and crocodile-like teeth compared to every other carnivorous dinosaur. And when you do the mechanical analysis, you see they function in a very similar way. And indeed. Teeth, oh, here's a spinosaurus teeth with very nearly circular cross section. Really distinctive, similar to crocodiles, similar to dolphins, similar to fish eating fish. So points to fish, crocodile like head, points to fish, crocs eat other stuff too, but still. Um, they're usually found in or near aquatic systems now.

• 2:18:50Speaker 01

  Fossils in general tend to turn up in aquatic systems because you've got to be buried to become a fossil. So water association is common, but even so, that's true. They turn up in places where lots of other dinosaurs don't tend to turn up, including carnivores, which suggests they're eating something else. Um, if you look at the isotopic signature of the teeth, um, often it correlates with crocodiles, fish, turtles and stuff that lives in water and doesn't correlate well with other land living dinosaurs that lived in the same time and same place. So you put all of that together and it's really hard to argue, oh, in addition to the tiny detail of baryonyx, the British one was found with fish scales inside its chest cavity.

• 2:19:34Speaker 01

  So you put all of that together and yeah, I'm not saying it only ate fish. I'm sure it ate big shrimp and turtles and we know they were predating on terrestrial dinosaurs and pterosaurs because again stomach contents and teeth and stuff. But fundamentally, this is an animal or a group of animals doing something different to the other carnivorous dinosaurs and it's probably linked to water and it's probably linked to fish as a predominant way of living.

• 2:20:00Lex Fridman?

  We should mention that you're working on a book out in early 2026.

• 2:20:04Speaker 01

  Um, so in the UK, it'll be out in November, in North America, January or February 2026.

• 2:20:09Lex Fridman?

  It's, it's called Spinosaurus Tales, the Biology and Ecology of the Spinosaurus. And uh.

• 2:20:14Speaker 01

  Written with Mark Whitten, who did that picture.

• 2:20:16Lex Fridman?

  It's a beautiful creature.

• 2:20:17Speaker 01

  Which I think is in there. He, Mark's done a ton of new artwork. He, he helped write the book, but he's also the, the artist.

• 2:20:23Lex Fridman?

  I mean, can you describe a little bit more about this creature? There's a, there's a bunch of stuff like what you just mentioned, there's some debate. Weird. Is it, is it, how, to what degree is it aquatic? So what, what?

• 2:20:34Speaker 01

  Not very, is my take.

• 2:20:36Lex Fridman?

  So does it live in the water? Does it step in the water?

• 2:20:38Speaker 01

  I, yeah. So I think it's basically a big wader. It's a poor analogy, but it's a very weird giant stork.

• 2:20:45Lex Fridman?

  Oh, got it.

• 2:20:46Speaker 01

  Or heron.

• 2:20:47Lex Fridman?

  Was giant.

• 2:20:48Speaker 01

  Um, yeah. So potentially bigger than T-Rex, linearly, not in mass. Again, really quite narrow chest versus that T-Rex barrel. But potentially 15 meters long. So bigger than any T-Rex we found, at least in terms of length.

• 2:21:02Lex Fridman?

  Can you describe what it looks like? The, I mean, there's some iconic features to it, right?

• 2:21:05Speaker 01

  Yeah. So this really quite long head, um, with a kind of wavy jawline, like, like animals have, you know, most carnivores have straight jaws. This one has a kind of, um, somewhat wiggly jawline. It really narrows at the front and then opens up again into like a little, it's called a rosette. So you've got like a little semicircle and then a dip and then the jaws go back and then the teeth line waves up and down. These really conical teeth, which doesn't sound very exciting, but it makes them different to every other carnivorous dinosaur. Like no other thing has a conical tooth, which is a classic fish thing, or at least biting hold of something that wriggles. Um, the nostrils are not at the tip of the nose. They're pushed back at least somewhat.

• 2:21:49Speaker 01

  It has a bunch of crests on the head. It's got quite a long neck. Spinosaurus and at least a couple of the other closest relatives to it, thing called Ichthyovenidae from, uh, I can't remember if it's Thailand or Laos. I think it's Laos. Has this giant elongated bit to the top of the vertebrae. And so it gives it this giant sail along the back. Spinosaurus, at least possibly Ichthyovenidae, probably not any of the others, then has this weird like thin, like mute like expanse to the top of the tail. Giving it kind of like a giant oar paddle appearance. Mostly they have very large arms with giant claws on the hands. Um, and Spinosaurus at least appears to have really quite short legs, but the others don't.

• 2:22:33Speaker 01

  Um, but again, so Spinosaurus is like totally iconic, but if you look at something like Baryonyx from the UK or, um, Sucomimus from Niger. It's still got the same head, it's still got the same neck, it's still got the same arms, but it doesn't have this sail and it doesn't have this tail and it probably doesn't have short legs. So Spinosaurus is super weird and exaggerated version of what is already a kind of super weird group of theropods. So Spinosaurus is properly strange. And then, as you kind of hinted at, like, super controversial as well, because various papers have claimed it's a diver or a really good swimmer. And I think the evidence for that is very weak at best.

• 2:23:16Lex Fridman?

  So your book is gonna be, you're gonna start some shit with your book?

• 2:23:19Speaker 01

  I think I already have, to be honest. Like, I've written, I've written three major papers and one in particular with my colleague, Tom Holt, where we frankly savaged the idea that it's a good swimmer. And then other people have since, including actually some of the authors who were on the original paper claiming it did swim well, have now effectively reversed their position and said it didn't.

• 2:23:42Lex Fridman?

  So the Jurassic Park three fight between the two?

• 2:23:46Speaker 01

  Yeah.

• 2:23:47Lex Fridman?

  Famous, real life encounter, who wins?

• 2:23:49Speaker 01

  So probably still T-Rex. I mean, the Jurassic Park Spinosaurus was pretty good for its time. Because some of the stuff that I've just talked about, particularly the short legs were suggested way back in 1910, 1912. But it was really uncertain. Now it appears to be more likely the case than not. The tail was unknown at this point, so it was just even a very generic tail. But the crocodile-like head is pretty good, the neck's a bit short, the sail is a bit too, like, it's almost just like a semicircle stuck on the back and it's a bit more complicated than that. But personally, I'm quite a big fan of the Jurassic Park three Spinosaurus. I think for its era, it's really quite good.

• 2:24:32Speaker 01

  It is massive. So there is this, they're from, I'm gonna say Morocco.

• 2:24:38Speaker 01

  Because Spinosaurus is found throughout North Africa, Morocco, Algeria, Egypt. There's a massive pair of jaws or snout that's in a collection in Milan. That's absolutely outsized, just like an absolute giant. And that points to a truly monumentally sized Spinosaurus, which is where all these upper estimates of 15 plus metres come from. It's just this one set of jaws. But yeah, it's about right, but it's just a bit too muscly and a bit too bulky. But in gross appearance, it's pretty good.

• 2:25:08Lex Fridman?

  Does it have a chance against a T-Rex?

• 2:25:10Speaker 01

  No, because it's got this unbelievably long, thin jaw, which whilst much stronger than something like baryonyx, is fundamentally not that strong. The jaws are very long and thin. And then the teeth are, yeah, they're big, but they're not big, big. You know, the whole, like, it grabs the T-Rex neck and then, like, snaps it. Well, Spinosaurus, actually, its neck is really strong going up and down. And he's very weak rotating or going side to side. So it's got the weakest kind of possible neck to like rotate and snap the T-Rex. And then T-Rex has got like the strongest neck of anything. So you've got like the weakest jaw with the weakest spin versus the strongest neck.

• 2:25:55Speaker 01

  So no, I don't buy it.

• 2:25:58Lex Fridman?

  So that brings it back to the topic we touched on a little bit. What are, you've mentioned a bunch of the stuff that the Jurassic Park series gets wrong. Maybe it gets depicted more things, but also what does it get right?

• 2:26:11Speaker 01

  So a lot of, like, very, in some level, generic, but quite important things it gets right. T-Rex is about the right size and shape and is massive. And you don't actually see it run, you see it power walk. If you watch the Jeep chase again, you'll see it only ever has one foot on the ground. The weird thing for me is how much some of them vary. So like, I'm a big pterosaur guy, I do lots of work on pterosaurs, the flying reptiles. The Tyrannodons in Jurassic Park.

• 2:26:39Speaker 01

  To the Lost World, you see them very, very briefly in one of the last shots. And they're okay, but they're not great. But it's clearly a bit of a throwaway shot. The ones in Jurassic Park 3, I think, are mostly excellent. Really, really good. And then the ones in Jurassic World are terrible. Like a massive regression. There's loads and loads of details that are right in JP 3 that are completely wrong in Jurassic World. And you're like, why did you take a really good model? And make it much, much worse and less accurate? I don't understand. Um, and I, again, it's fiction. At one level, who cares? But like, as, as you said, like, I, I don't think, so see, the weird thing for me is,

• 2:27:22Speaker 01

  I don't think it would affect how they're perceived by the public. Some things I get, like, for example, in Jurassic World, the tyrannodons pick people up with their feet and fly off of them. Tyrannodon's feet don't work like that. It would never be able to do that. And it would never have the lift. But I get for dramatic purposes, you might wanna show that. Okay, fine, you know, this is your big sequence. You need that. But for the rest of the animal, it's weirdly inaccurate. And I don't think the public would know. And they might well care if it was much more accurate. And I don't think it would be any harder to make it accurate than to make it inaccurate.

• 2:28:04Speaker 01

  Um, I've spoken to a colleague of mine, who I won't name, just in case I get him into trouble. Um, who's a big dinosaur nerd, but also a big creature creator and designer, and has done a whole bunch of proper Hollywood A-list movie stuff. And I asked him about this and I went, okay, but like, is it just easier to take the model that you've got and mess around with it than to, if I came in and said, you need to fix that, you need to fix this, you need to fix this, you need to fix that? And he basically went, no, it's about the same amount of effort. It's not like.

• 2:28:37Speaker 01

  We don't have the director or the producer or the lead designer going, no, I want that arm a bit longer. I want that tail a bit brighter. Can you add a few more bits there? I don't like those scales. So he said, we're doing that constantly anyway. So doing it to one set of design specs versus another set of design specs is no more hassle. In other words, he said, it's no harder to make it accurate than to make it inaccurate. And it's like, if that's truly the case, then just make it right. And then you can claim a level of accuracy and engagement that you can. I mean, it's interesting. There's, there's a thing called the Jurassic Foundation. After the first Jurassic Park, made an absolute fortune. Spielberg, I think it was Spielberg directly, maybe been through Universal.

• 2:29:18Speaker 01

  But anyway, they set up the Jurassic Foundation and it's a small fund of money for research on dinosaurs and related animals. And academics can apply for it. My PhD, one of my PhD students got some money from the Jurassic Foundation. Like, that's great. He didn't have to do that. He went paleontology's helped give me this. I'm going to give back a bit and after what must be 30 years now, it's probably funded an awful lot of research and help young researchers get started. So there's a level of engagement there that I think hasn't been in subsequent films, which you can kind of see for once it goes from being a one off to being a franchise and it's changed hands. I mean, how many different directors has it had now?

• 2:30:00Speaker 01

  You know, Spielberg did the first two and then done about the next five, must be two, if not another three more people. You know, and 30 years later, it's, it's, it's all changing.

• 2:30:10Lex Fridman?

  Yeah, but that's the path of creating a legendary film.

• 2:30:13Speaker 01

  Yeah.

• 2:30:14Lex Fridman?

  That, that depth of accuracy and it's not that difficult to work, but it's also, it does something to the, to the whole artistic creation. If you create a culture of where the details really, really matter.

• 2:30:24Speaker 01

  Yeah. And, and again, there's, there's some oddities. So like Gallimimus, I've mentioned it earlier. So one of the ornithomimosaurs, the model for Gallimimus in Jurassic World is nearly identical to that from Jurassic Park. One of the differences which you can barely see on film, but I know this is true because I found it in like Jurassic World kids book. Cause I flicked through it when it came out. So close up of the head with an arrow to the teeth. Gallimimus doesn't have teeth. It's got a beak. So someone has taken the original model and actively spent time adding teeth to an animal that didn't have them. I would understand it. I'm not saying I agree with it, but I'd understand if it was a rule of cool and like,

• 2:31:06Speaker 01

  yeah, but it would look so much better with all these gnarly big teeth and whatever. And it's like, you can't even see it in the final thing. They've got tiny little heads. In the film, all they do is like run past the camera briefly. It's not like they're a big carnivore and they're engaged in like one of the big battle. Like, why? Why? It's not like, you can't even barely see them.

• 2:31:26Lex Fridman?

  Uh, well, yeah. Again, just to linger on it, there is a lot of value to authenticity in all walks of life. And one of them is accuracy. When you're talking about dinosaurs, it's so valuable and so worthy and it's respectable for the long life of a film to be accurate. I just wish, I, I hope they do that. There's certain directors that really dogmatically push that. Alex Garland comes to mind. You know, he, he did, whenever he integrates like quantum computing or AI into a film.

• 2:31:57Speaker 01

  Nolan with the black hole in Interstellar, where they ended up publishing a paper on the calculation to visualize.

• 2:32:03Lex Fridman?

  I mean, that's legendary. That's great. That's really, and like, you think that has nothing to do with the story, the narrative of the film, but it does. It like permeates everything. If you get that black hole right, that everybody else steps up their game and really, really tells a story in this way that reverberates through time and it like really moves people. So.

• 2:32:24Speaker 01

  Yeah, I, yeah. I mean, as I say, I, I, I wish it was better. I mean, the, the only thing I'd, I'd flip it around. It's a joke I've made more than once, but like, just, just don't take it as a documentary. No one wants, watches James Bond and goes, that's how international espionage works. You know, he's got the laser watch and the exploding car and he's like, may, maybe treat it a bit as fiction. I, I, I've heard from a friend of mine who worked at, uh, the Royal Tyrrell Museum, which I've, I've mentioned before in, in Alberta, which is an absolutely phenomenal place. Um, and she said, after the first one, genuinely, like, it was not common, but more than once,

• 2:33:08Speaker 01

  people were annoyed that they didn't have the real dinosaurs out back because they'd seen them and they knew that the real ones were out there. Which is a testament to industrial light and magic and Stan Winston, but also slightly horrifying that anyone watched Jurassic Park and literally thought that mu- Also, why do you go to a museum? You go to the zoo if it's alive.

• 2:33:29Lex Fridman?

  There you will also meet, uh, what is it? King Kong and Godzilla?

• 2:33:32Speaker 01

  Yeah, yeah.

• 2:33:33Lex Fridman?

  Uh, I don't think it would quite touch on this. I really want to ask you about, uh, intelligence. What we know about the intelligence of, let's say, T-Rex. We talked about his big head. What do we know about?

• 2:33:44Speaker 01

  Not much. So there's, there's a T-Rex brain, or at least a very rough cast of part of one.

• 2:33:52Lex Fridman?

  That's the actual look of?

• 2:33:53Speaker 01

  Yeah, that this is, so dinosaurs, in fact, most reptiles, I wonder if you can see it on the velociraptor? Not really, unfortunately.

• 2:34:02Lex Fridman?

  Elongated.

• 2:34:03Speaker 01

  Yeah, but it's more that they have, we are weird in that we have a brain that basically fills the inside of our skull. What most animals have is actually a little kind of sub skull inside the main skull, which is called the endocast or endocranium, and the brain is in that. And even then, it's not like full of brain because we've packed an awful lot of brain into our limited space. And they then have quite a lot of goo and fat and other stuff around it. But it means for dinosaurs and then deep reptiles and birds in general.

• 2:34:39Speaker 01

  In the old days, you could basically cut one open, but now we'll CT scan through them. You can take an internal mold of the endocranium, the brain case, and then whatever filled that would have been the brain and its surrounding tissues. And that's how you get something like this. In this case, someone literally cracked open an old skull and basically took an internal mold in the same way that you do an external mold for the, for the skulls. And that tells you quite a lot about certain things. So for example, you've got a bulb at the front, which is the olfactory bulb. So brains are very stereotyped. Again, ours are super weird. So you have your factory bulb at the front and define that you have the optic bulb or the optic lobe.

• 2:35:20Speaker 01

  So roughly how big they are will tell you roughly how much of the brain is devoted to, for example, sight and smell. So if it's a lot, it's pretty good. If there's not much, it's not very good. That goes quite a long way already. One thing we've done in the last few years is you can also get into the, it's not shown here, it wouldn't be part of this, uh, but the inner ear. We can CT scan into the structure of the bony inner ear. And from that, you can actually get an idea of what frequency of sounds the inner ear was structured to be pitched to.

• 2:35:53Lex Fridman?

  Wow.

• 2:35:54Speaker 01

  Which is, doesn't actually tell you very much, but it's phenomenally cool that you can do it.

• 2:35:58Lex Fridman?

  We should say you also have quite a bit of a background in biology. So you're trying to reconstruct biology from, go from paleontology to biology?

• 2:36:07Speaker 01

  Yeah, I, my, my go to one liner is I'm a zoologist, but I work on dead stuff. My degree was zoology. My official job title now is Reader of Zoology. I teach zoology. I don't teach paleo. So yeah, living animals was always actually my primary interest and I kind of fell into paleo. But then I wanted to drag that with me because I'd been trained in behaviour and ecology and it's what I was most interested in. So then applying that knowledge and understanding to these animals.

• 2:36:38Lex Fridman?

  So to some degree, it is possible to reach towards the biology?

• 2:36:41Speaker 01

  Absolutely, yeah.

• 2:36:42Lex Fridman?

  So with the ear, that's interesting. The brain, so we can know something about the brain?

• 2:36:46Speaker 01

  Yeah, but then, but then when you get into intelligence is when it gets really awkward because working out exactly which bits of this are probably linked to like the main fundamental processing and what you link to actual intelligence is tough. On top of that, we don't really know what's been the big challenge of the last couple of years. This question was T. rex and other dinosaurs, super intelligent of like neuron density. How many basically nerve cells can you pack in per bit of volume? Cause birds have some weird tricks, which means they get a lot more brain per volume. Just how much of the brain case was brain and how much was like goop around it, we know varies. So you get a kind of fairly big upper and lower band.

• 2:37:29Speaker 01

  And then the other big thing we always have to do is factor in size. Big animals need bigger brains to operate them. So whales have really big brains, but whales weigh tens of tons. They're not smarter than us. So you have the, the classic thing is I think called the encephalization quotient, which is at a very simple level, it is the volume of brain scaled against the size of the animal. So we have huge brains compared to how big we are. So we're massively up the chart. And then you do have a few things with like worms. I should probably stick to vertebrates. These are some stupid stuff which has a surprisingly small brain for its size.

• 2:38:07Speaker 01

  Most things that aren't primates and things like crows and parrots sit very neatly on a couple of different curves. There's a curve for reptiles, a curve for birds, a curve for mammals and things like this. Um, and basically that's it. But also actually our understanding with mass estimates for dinosaurs is good, but not great. And so you could easily be out by, you could easily be out by like 20 or 30% on the volume of the brain inside the brain case. And then you could be out by 20 or 30% on your mass estimate. Well, now suddenly it's very easy to make the brain too big and the animal too light and it's super smart. Or make the brain too small and the animal too heavy and it's super dumb.

• 2:38:52Speaker 01

  So that's awkward, unfortunately.

• 2:38:55Lex Fridman?

  So apparently there's some controversial paper that suggests that T-Rex has primate level intelligence.

• 2:39:00Speaker 01

  Yeah. And then that was shot down within a few months by a team of paleontologists and a couple of other neurologists. Who really went to town on it.

• 2:39:10Lex Fridman?

  Just counting the number, try to estimate the number of neurons.

• 2:39:13Speaker 01

  Yeah, it was the neuron density thing. And yeah, I, I, I've unsurprisingly support the revised one, which was done by a whole bunch. Yeah, the Caspar paper. Um, I've spoken to Caspar about it, a couple of the other authors.

• 2:39:26Lex Fridman?

  So they scaled down the number of neurons from three billion down to 250 million to 1.7 billion, which is similar to crocodiles, not.

• 2:39:36Speaker 01

  Yeah, which is kind of what you'd expect. I mean, a couple of other peoples at various times have suggested they're really smart. And again, you know, birds have this thing of, they have this weird thing of neuron folding and they can basically pack in a lot more than you'd expect. You know, that's why crows are that smart despite having tiny brains relatively, even compared to their overall size. Um, but.

• 2:39:59Speaker 01

  I'm being obviously overly facetious, but if ultimately part of your scaling is how big is the animal versus how big is its brain? That's most of a T-Rex brain. It's a fraction of the size of a chimp brain and chimps don't weigh seven tonnes. So you, you, you know, it's a kind of Hitchens like extraordinary claims require extraordinary evidence, but like you just look at it and go, that's about the proportion we'd expect for a croc. Now, crocs are smarter than people think, but they're sure as hell not monkeys. Um, you're gonna have to really come up with something much more convincing than, oh, if you just pack them and if you scale them this way.

• 2:40:41Lex Fridman?

  A bit of a ridiculous question, but is it possible to find evidence of tool use?

• 2:40:45Speaker 01

  I mean, in theory, it, it depends how you, quite how you define a tool. So birds building nests is arguably tool use to a certain degree. I'm aware of.

• 2:40:57Speaker 01

  I, I suspect it to turn out not to be the case. I was, I was shown a very rough, not very well-prepared fossil.

• 2:41:07Speaker 01

  Twenty years ago now, no, fifteen years ago now, where someone said, we think this might be a early bird nest and therefore potentially even a dinosaur nest. And nothing's ever been published. So my guess is once they excavated it and had a good look at it, they went, nah, it's nothing really. I mean, I guess the question is, how would you know?

• 2:41:26Lex Fridman?

  Yeah, it would be difficult unless it's obvious, widespread, primate.

• 2:41:31Speaker 01

  Yeah, but even then, like, you know.

• 2:41:32Lex Fridman?

  Sapient.

• 2:41:33Speaker 01

  You know, chimps, chimps make loads of tools, but it's mostly made of wood and they're mostly just breaking stuff. And then that's, the odds of that preserving are very low. You do get things like chimps and otters, sea otters, they have their favourite anvil and hammer stones to break stuff open. But again, the reason they picked that stone is because it's really heavy and good at breaking oysters or breaking nuts. It's not gonna leave, or probably not gonna leave stereotypical points on the rock. And even then you could just go, well, maybe it.

• 2:42:05Speaker 01

  You know, just got bashed up in a river or something.

• 2:42:08Lex Fridman?

  So in your book uncovering dinosaur behavior, you you kind of conclude that there's a lot we might not know. What's a particular lost behavior that we don't know about that you think might be out there?

• 2:42:19Speaker 01

  Something like midden use. It's a whole bunch of animals and birds who basically crap in the same spot. They they have their spot and that's where they go. So rabbits do this, sloths do this, um, aardvarks, even things like wildebeest and zebra, uh, not zebra, uh, impala would tend to go back to the same place every day. But the fossil record of so coprolites fossilized feces and fossilized waste from dinosaurs, it exists, but it's extremely rough because of course this is the stuff that's already been digested and broken down. It's already kind of gooey and broken up and doesn't have a lot going for it.

• 2:43:01Speaker 01

  If they do it in water, it's going to dissipate instantly. If it rains, it's probably going to fall apart. Things like dung beetles and flies will break it down. Even if it gets covered by sand or whatever from a sandstorm, it's probably still going to compress and separate. So are you ever going to find it? Maybe going going back to our trackway stuff, but even if you do, what species? Left that we know a big herbivore did this, but was it triceratops or was it an ankylosaur? Those animals are very different things, doing very different things, and it would tell you different things about their behavior if we know.

• 2:43:34Lex Fridman?

  Yeah. So one one piece of behavior I forgot to ask you about, uh, so T. rex engaging cannibalism.

• 2:43:41Speaker 01

  Yeah, almost certainly. Well, certainly. I think we've got, um, there's a T. rex bone with a T. rex embedded tooth in it. With overgrowth.

• 2:43:50Lex Fridman?

  Yeah.

• 2:43:50Speaker 01

  There's, I think it's, I want to say it's an Albertasaur rather than T. rex. But there is a nut, there is a tyrannosaur jaw in Alberta with a T. rex tooth stuck in it. And you can pull the little tooth out. Um, and then there's a T. rex foot bone with these distinctive feeding traces on them. And this actually goes back to that early point about T. rex being weird, being the only big carnivore, it's an environment. Because if this was even Mongolia at that time, but anywhere else, there's three or four or five big carnivores. And so you find a bone and it's chewed up by a big carnivore, we don't know who did it. But when you see a big bone chewed up in a T. rex ecosystem, well, you know, if it's anything bigger than this,

• 2:44:35Speaker 01

  you know, it was T. rex. And so when it's a T. rex bone with T. rex bite marks.

• 2:44:40Lex Fridman?

  Yep.

• 2:44:41Speaker 01

  Q E D, yeah. So it must have been.

• 2:44:44Lex Fridman?

  That's fascinating, isn't it? That they would attack themselves.

• 2:44:48Speaker 01

  My cannibalism turns up in a whole bunch of stuff.

• 2:44:54Speaker 01

  But it's not, it's very rare as like a fairly habitual behaviour.

• 2:44:59Lex Fridman?

  So but there's several reasons you might be engaging in, or rather teeth marks might tell various stories. So it could be just fighting for dominance, right?

• 2:45:10Speaker 01

  It it could, but it's unlikely. And in this case, so again, we see there are loads of facial injuries in tyrannosaurs, in carnivorous dinosaurs generally, but particularly tyrannosaurs. They have really beaten up heads, like half or even two thirds of adults have scarring and facial injuries, but you see healing on it. Whereas this foot does not show healing and it's got multiple different bites. The idea that you'd bite a foot whilst fighting someone and then go back and bite that one foot again. That's pretty, not impossible, but pretty unlikely.

• 2:45:42Lex Fridman?

  So it looks like it's eating, not fighting.

• 2:45:44Speaker 01

  Yeah. And they're more like the feeding scrape traces than they are the big puncture wounds. So again, not impossible, but very weird for that to occur as a fight.

• 2:45:53Speaker 01

  So, yeah, they're they're they're fighting. They're fighting probably quite a lot. But whether or not you actually eat something that you've killed or that you stumble across as a body, it's definitely happens occasionally, otherwise we wouldn't have the record of that. But there's a reason carnivores often don't eat carnivores and particularly don't eat their own species, which is parasitism. You know, carnivores in general are loaded with parasites because they spend their whole lives eating food which has parasites and stuff in it. And so they tend to accumulate a lot of them. What's the one thing that's going, definitely going to have the most parasites in it that can infect you as, for example, a lion? It's another lion that eats the exact same stuff that you do.

• 2:46:37Speaker 01

  So whilst it is food, and particularly if you've just won a big fight, you might want to eat. In general, cannibalism is pretty rare because it's generally not a good idea if there's other food available. But yeah, if you're starving to death, or, you know, the other guy ripped your leg half off and you're going to walk for six weeks, not that you'd think, but you know what I mean? Like, and now, and now there's a body in front of you, it's two tons of meat. Well, maybe you should tuck in.

• 2:47:05Lex Fridman?

  This is so fascinating. Like, once again, figuring out this puzzle. And like, what does cannibalism tell you? You're piecing together the story of T. rex, their, their life, their hunting life, their social life, from their evolution to their biology, to their behavior. It's so fascinating.

• 2:47:21Speaker 01

  Yeah, we, we try to. But the thing is, it's, it's, it's always getting better, which is, so that's what I tried to finish on in my book on behavior is, I felt I'd written a couple of hundred pages of, we keep screwing this up, we've overstated this, I think people have misunderstood this, this, you know, the trackway stuff, and it's like, this is not as confident as we think, you need to look at these alternate explanations, this behavior shows that that behavior probably doesn't correlate the way you said it does, yada, yada, yada. And it's like, I now feel like I've just written a book trashing my entire field and all my colleagues, or at least many of my colleagues. And then, then you, you flip it on its head and going, we've got techniques that were undreamed of 10 years ago. We've got data streams that were undreamed of 10 years ago. And we've actually

• 2:48:06Speaker 01

  got a much better understanding of living species. And then on top of that, we're just constantly finding new animals. You know, we have not just new species, which are often, I think, a lot less important, but just new specimens of ones we know. Because again, it's building up that database. You know, we drifted off talking about sexual selection, but like, yeah, you, if you want to know growth, one or two animals doesn't tell you how an animal, a species grows, 50 or 100 does. And then that reveals a hell of a lot more about things like sexual dimorphism and growth rate and how vulnerable juveniles are and population structure, and maybe how they're reproducing. So I'd like to think I knocked down, I think I knocked down a few towers that probably a few people were fond of. But I think we have the raw materials to build much better, stronger edifice of

• 2:48:52Speaker 01

  behavior. But as you say, it's, it's always going to be based around often very piecemeal evidence and like possibilities and probabilities rather than certainties.

• 2:49:05Lex Fridman?

  Well, let's talk about a sad topic, extinction.

• 2:49:09Speaker 01

  Yep.

• 2:49:11Lex Fridman?

  How did the dinosaurs go extinct?

• 2:49:14Speaker 01

  Mostly, probably pretty quickly, but it really is the answer that I think most people are now probably familiar with, which is it's an asteroid impact or some kind of extraterrestrial body hit just off the coast of the Yucatan Peninsula in Mexico about sixty six million years ago. That basically atomized the asteroid, but also importantly, the bit of the ground it hit or below the seabed that it hit was basically the worst kind of rock. And so it put up this enormous ash cloud and basically you have a nearly instantaneous nuclear winter. I mean, immediate devastation, you know, anything immediately next to it is obviously just like vaporized.

• 2:49:58Speaker 01

  But you know, this is the sort of thing that it's like hot enough to set fire to the atmosphere. I think the one I read was it's something like a piece of rock about the size of Mount Everest, traveling at something like ten times the speed of sound. So just the momentum between that speed and mass thing is just, you know, beyond extraordinary.

• 2:50:19Lex Fridman?

  But I think what does a lot of damage is the change in the climate.

• 2:50:22Speaker 01

  Yeah, and so, so every, there are five recognized mass extinctions in the history of life on earth, and all of them are ultimately some form of climate change. Whether it's volcanic eruptions or hyperoxygenation or an ice age or whatever, it's, it's, it's climate changing too quickly for things to adapt to. And that starts, you know, that just cripples entire populations and entire species. And then if you do enough damage to enough things, you start getting ecosystem collapse. You know, this moth has died out. Well, it turns out that moth is the primary pollinator of this tree. Well, that tree produced nuts and that was the entire winter survival store for this squirrel.

• 2:51:03Speaker 01

  Well, that squirrel was the main food of this cat and now suddenly the moth going has killed four other things and, and everything that's attached to that. So that, that's really what did for them.

• 2:51:17Lex Fridman?

  And sadly, the big things, well, everything dies, but the big things have a lot of trouble recovering.

• 2:51:23Speaker 01

  Yeah, so I mean, this, this is.

• 2:51:27Speaker 01

  You know, a classic example, so, oh, well, you know, what is paleontology good for? Well, one actually really is extinction, which is very relevant right now in that we have a very good handle on when you have extreme climate stress, what tends to suffer more and what tends to suffer less. And as we say, big, big things fundamentally do. They require more resources, they require more area of land, you need to roam further, which means, you know, if you're a mouse and you happen to have a little bit of land and that bit doesn't get hit, you're fine. Whereas if you're an elephant and you need all of this land and even a chunk of it goes wrong, well, that's probably maybe not enough for you to survive anymore. So, yeah, big things suffer disproportionately badly from these things.

• 2:52:12Speaker 01

  And mostly as well, we think terrestrial things generally do worse than things in water because water is a great equilibrium eating medium. You know, it takes ages to heat up, it takes ages to cool down. Yes, if you live in specific coastal conditions or something, maybe you can't travel that easily, but, you know, whales can go from pole to pole quite happily and plenty of other fish do too. So if it's too hot or too cold or too nasty here, you can just swim somewhere else. Whereas if you're an animal and you hit a desert or you hit a mountain range or you hit a river, you stop moving and you're trapped and, and then you die. So dinosaurs, well, yeah, the, the worst possible combination, they were mostly big and they were mostly on land.

• 2:52:57Speaker 01

  And, yeah, it's not really surprising they did very badly out of it.

• 2:53:01Lex Fridman?

  And then some species did survive. Uh, I guess, I think you've said that it's, it's very possible that some dinosaurs even survived for a time that we, we might be able to discover down line.

• 2:53:12Speaker 01

  I'd be amazed if they didn't. I mean, there's been various reports over the decades of.

• 2:53:19Speaker 01

  The KPG or KT extinction, the Cretaceous Paleogene or Cretaceous Tertiary extinction of dinosaurs surviving, and none of them have held up. It's usually been bioturbation. So literally things like prairie dogs digging, and of course they'll dig a tooth up and then move it through the layers or things like this, or plant roots can move stuff. Or just soils can get churned up. But I would be shocked if they didn't. Not like, oh yeah, the dinosaur survived and the lock next monster and stuff like that. But like, yes, it was a global devastation. Yes, it's what ultimately killed the dinosaurs. But I'd be amazed if there wasn't some equivalent of Hawaii or New Zealand or some other tucked away island

• 2:54:02Speaker 01

  or valley where actually dinosaurs were fine for anything from a few hundred thousand to a couple of million years. But on a global scale, it's a dot on a map. And the odds that we'll ever uncover any rocks, fossiliferous rocks of that age that we then have access to, that we then find a dinosaur in, that we can then date properly, I think is almost non-existent. But it would just be weird if they didn't survive somewhere for a bit, or even quite a few of them in places.

• 2:54:32Lex Fridman?

  So small local population.

• 2:54:34Speaker 01

  We see it all the time. You know, the lemurs in Madagascar, all the stuff in New Zealand. There's tons of weird archaic stuff hanging around in Hawaii, you know, Galapagos finches and tortoises, if there are tortoises that you don't see anywhere else. In Australia with the marsupials, they're almost, and then the monotremes are almost unknown outsider there. This is pretty normal bit of biology for animals that were so dominant globally. We know there were patches that were largely unchanged. Otherwise, we wouldn't have had the mammal surviving and the crocodile surviving and the bird surviving and newts and frogs and everything that did survive. I'm sure a few of those patches had some dinosaurs in them, but it is ultimately what killed them.

• 2:55:18Lex Fridman?

  What do you think is the chance that they would have survived? So you take some local populations and they flourish?

• 2:55:24Speaker 01

  It's happened. Look at Australia. You know, the marsupials have done pretty well there for a very long time. You can imagine if the next mass extinction.

• 2:55:36Speaker 01

  You know, flattens a large chunk of Indonesia, for example. Kangaroos could island hop pretty easily, make it to mainland Asia.

• 2:55:45Lex Fridman?

  But then, I mean, to then lead, you take the dinosaurs, a small fraction survives and then they eventually repopulate the earth again.

• 2:55:54Speaker 01

  I mean, that's extraordinarily unlikely because once your population's been crashed like that, you do have the problems of things like inbreeding, or maybe you're a great specialist to a certain area, or you're surviving because you're isolated, you're in a, you're in a valley or you're on an island and then dispersing again becomes really, or breaking out into those areas becomes much, much harder.

• 2:56:14Lex Fridman?

  So like the great predators, like even though the T. rex is such a great predator, that doesn't, that doesn't give you.

• 2:56:20Speaker 01

  Yeah, because, because you've still had the extinction event and the environment is no longer what it was that you evolved into. Um, and when, once those systems start to recover, those other animals are going to adapt much better to them.

• 2:56:33Lex Fridman?

  How's that make you feel? That, that, um, this stupid asteroid from nowhere.

• 2:56:42Speaker 01

  I mean, at one level, I probably wouldn't be here if it hadn't.

• 2:56:45Lex Fridman?

  So I mean, that's, that's an interesting question. I mean, do you think, um, there's several ways of asking that question? But if dinosaurs didn't go extinct, do you think humans would still be able to evolve?

• 2:56:55Speaker 01

  I mean, my guess is probably not. I don't, I don't think, I don't think it's quite the, um, what, what was it? Oh, Simon Conway Morris had that book, was it inevitability of man that like, even if you rewound it, everything would come back. I'm, I'm not, I don't think it's that far. Um, I certainly don't think it's, um, anything like, quite like the butterfly effect of, you know, if one mammal had been trodden on by one T. rex, then humans would never have evolved either.

• 2:57:24Lex Fridman?

  We should say that the, uh, ancestor of the primates or the closer, there's a lot of debate around this. Uh, it's a kind of tiny creature purgatorious that was our ancestor. Yeah. So this is us. This is what we evolved from.

• 2:57:39Speaker 01

  Yes, uh, Scandentia, I think it's the group.

• 2:57:42Lex Fridman?

  Basically a rodent.

• 2:57:42Speaker 01

  Yeah. I mean, there, there were probably primates around in the Cretaceous. Some of the molecular clock stuff suggests that primates were around alongside the dinosaurs that we've never found. Um. Any osteological evidence of that. But yeah, there's been a backwards and forwards amount. Were dinosaurs already on their way out or were they a bit limited by the very end Cretaceous? I think the more recent analyses have shown that's probably not the case. So in other words, they were basically doing fine. Right up to the extinction event. And so, yeah, if the asteroid hadn't hit, there's no reason to think that they were on some kind of terminal decline. Something else may have hit. There may have been.

• 2:58:24Speaker 01

  You know, some other environmental disaster or something may have happened, or maybe they're more vulnerable to stuff.

• 2:58:32Speaker 01

  Than we know of, but there's no, I don't think there's any really good reason to think.

• 2:58:39Speaker 01

  They wouldn't have carried on relatively well. I mean, even post dinosaur extinction. You had a window where the mammals and the birds were pretty competing. There's a lot of big birds getting going and various big carnivorous terrestrial kind of hyper predatory ostrich like things like the Forseracids. So there's no guarantee that mammals would have even taken over post the dinosaur extinction. Since initially they were in a bit of a a fair bit of competition.

• 2:59:08Lex Fridman?

  So this is just going to, based on current scientific understanding, human evolution would be highly improbable if dinosaurs hadn't gone extinct 66 million years ago. Because dinosaurs dominated ecological niches.

• 2:59:19Speaker 01

  For everything, basically. I mean, that's the thing, you, you, you look through, yeah, the Mesozoic, the Late Triassic. Dinosaurs are there alongside a whole bunch of other big and unusual and interesting reptiles and, and some other early pre mammal like things that are closer to mammals than, than the reptiles. But once you've gone into the Jurassic, you've now got a solid like 120, 130 million years. Where almost anywhere on earth, if you saw an animal bigger than like a raccoon, it was probably a dinosaur.

• 2:59:52Speaker 01

  That's how incredibly dominant, you know, as dominant, if not more dominant than modern mammals.

• 2:59:58Lex Fridman?

  But is it fair to say that they were mostly dumb?

• 3:00:02Speaker 01

  I don't think so, because I think that comes down to, A, that bit of kind of classic, almost Victorian speciesisms, and you get these insane hypotheses like dinosaurs as a species or as a lineage became senile, so they forgot to breed. That was literally a suggested idea. You know, the mammals ate their eggs and all of this kind of stuff, you know, dinosaurs only lived alongside mammals for 100 million years. It'd be weird if they all went extinct at the same time because suddenly egg eating evolved. You know, you've got problems like this. But also, again, that that general speciesism, which, you know, even goes back to the flight Linnaeus and his taxonomic ranks and even stuff like

• 3:00:44Speaker 01

  Aristotle, you've got like, you know, humans are superior in some way, and we're superior to the other mammals. And of course, mammals are closest to us, so they must be quite good. And then they've got to be better than lizards, and then lizards have to be better than frogs, and frogs have to be better than fish. So that that gets you into the, well, reptiles must be stupid. And and they're not.

• 3:01:08Lex Fridman?

  I wonder if a human intelligence level organism could have evolved from the dinosaurs.

• 3:01:13Speaker 01

  I mean, it's that's been hypothesized plenty of times. Dale Russell, Canadian paleontologist, the famous guy who came up with this human-like truodontid that was done for a TV documentary, I think the one that Christopher Reeve narrated. That, I think, is a remake, but I've seen the original that Dale had made for his TV show, and it's still, it's sitting in the collections of the National Museum of Nature in Ottawa for Canada. It's really, really cool. It's like this five foot tall dinosauroid, that was it there on the screen.

• 3:01:44Lex Fridman?

  Model of the hypothetical dinosaurid and displayed at the dinosaur museum in Dorset.

• 3:01:48Speaker 01

  Oh, Dorset, that's in England. Yeah, I knew there was a couple of copies of it. Trudon always comes back as like the most intelligent dinosaur because it has really quite a big brain for its size. It does have a high encephalization quotient, so it's always been like tagged as like a very good candidate for being the smartest dinosaur. And basically, he just hybridized that with a human. But of course, why would these things end up as like plantigrade quadrupeds? And why would they go back to five fingers? And actually, I think he's only got three, to be fair, but he's got very human-like feet. Why has it got no tail? Why would those things suddenly disappear? There's no real reason other than just kind of human exceptionalism. But like, I mean, you could argue some parrots, some crows are

• 3:02:32Speaker 01

  phenomenally intelligent and show extremely clever behaviors on a par with apes. So at some level, some dinosaurs were extremely intelligent.

• 3:02:43Lex Fridman?

  I mean, yeah, this is a whole nother conversation, but all the tiny details that lead to the explosion that is in the evolutionary tree that is Homo sapiens, like what is it opposable thumbs, right? Is it the invention of fire and the meat eating? Is it?

• 3:02:58Speaker 01

  Yeah, and sociality and predation pressure and then the changing environment. I mean, the shrinking of the forest, pushing apes out of the trees into the environment or into the open environment.

• 3:03:10Lex Fridman?

  And probably the same kind of story could be told about the dinosaurs or about about anything, really.

• 3:03:14Speaker 01

  Yeah, I mean, I mean, if you have 160 million years and a global domination, but I mean, this is the thing, you talked about like lost behaviors, but like the lost lineages, I wrote about this in one of my books and like, you want to find, you want a weird animal, you go to a volcanic island. Like you go to New Zealand, you go to Hawaii, you go to the Galapagos. And yet those are the places that basically don't really form fossils. So you think the dinosaurs we know about are strange. What was the stuff knocking around there? We're never gonna know, sadly, but for everything you think weird, you know, you think birds are cool. Think about penguins compared to your average bird. They live on

• 3:03:56Speaker 01

  an ice shelf for six months of the year and can't fly and massively modified skeletons and you know, you're compared to your average bird, penguins are unbelievably weird. So yeah, take an average dinosaur and take it to like penguin level ostrich level evil or hummingbird level evolution. There's gonna be weirder stuff out there than we've found, much weirder.

• 3:04:22Lex Fridman?

  If you travel back in time, you probably, your mind will be probably blown by the weirdness.

• 3:04:27Speaker 01

  Yeah, because those things are almost always in small, isolated places that don't preserve fossils very well. And so the odds of us ever coming across them, I mean, you, you see it to a degree. So you've got, um, the stuff that comes out of, uh, like what is modern Transylvania, Hatseg. That, that's, that was a series of islands in the Mediterranean at the end of the Cretaceous. And some of the weirdest dinosaurs are from that chain of islands. And that's not very isolated compared to, again, something like Hawaii or New Zealand. But it's fitting the exact pattern. You, you get dinosaurs on islands, they turn weird. We, we see that. So again, dinosaurs were real animals.

• 3:05:10Speaker 01

  Like, again, sounds, sounds really painfully obvious, but they, they weren't monsters. They followed the same rules might be pushing it, but sort of like guidelines, like ecology operates in certain ways. If you're bigger, you need more food, but you're more efficient. You just are. That's pretty much just physics and scaling. So big dinosaurs are going to follow the rules of bigger animals and small dinosaurs are going to follow the rules of smaller animals. They just will. Quite how they violate it in certain ways by having unusually long necks or unusual physiology or eating an unusual diet or because there was a weird plant that was alive then that isn't now, or whatever it may be, that there's obviously a huge amount of variation and uncertainty.

• 3:05:56Speaker 01

  But fundamentally, we know what makes animals and ecosystems work and dinosaurs are animals in ecosystems. They're not that strange at some level and therefore reconstructing their actual biology is challenging, but far from impossible.

• 3:06:15Lex Fridman?

  Strange question. So as everybody knows, dragons are obviously real.

• 3:06:21Speaker 01

  I've been asked that on live TV before, only not with the sarcastic tone.

• 3:06:27Lex Fridman?

  Do you dare disagree with this notion?

• 3:06:31Speaker 01

  Yes, I do. They don't. And again, I

• 3:06:34Lex Fridman?

  They're real to me, so.

• 3:06:36Speaker 01

  That's fine. But again, you know, we kind of touched on it, but I think there's probably very little of any kind of paleontological lore that ended up in things like Chinese culture with the Chinese dragons and all of that stuff. You know, that one comes up repeatedly. The only one I do know of, again, from Alberta, is buffalo stones that then apparently some of the Native Americans had, which are actually bits of ammonites. So ammonites, the curly spiral shelled cephalopods are related to octopus and squid. So they have all these little segments to the shells and the right species, when they break open, they have like two little pairs of legs and then a bulge and then a little bulge and it looks

• 3:07:20Speaker 01

  very roughly like a bison. And apparently these were thought to be like somehow miniature bison. They're very rare because ironically, although the dinosaur bones are extremely common, it was very swampy and so you didn't actually have a lot of sea coming in. So you didn't tend to get things like ammonites and ocean going animals. And then the shell would have to break in the right way. But apparently for the local tribes, sadly, I can't remember who it is in that bit of Canada. But yeah, these were, these were quite valued. If you've got a buffalo stone, and I've seen a couple of them, and yeah, you have to squint a bit, but as a little buffalo, it's not far off. But yeah, but that whole like, were they finding mammoth legs and were they finding T. rexes?

• 3:08:02Speaker 01

  And was this inspiration for this animal or this mystical animal? I don't think they were because you just don't tend to find them.

• 3:08:08Lex Fridman?

  So where do you think like, you know, because dragons show up in a bunch of different myths?

• 3:08:12Speaker 01

  Well, right. But the thing, they turn up in British mythology and we've barely got any dinosaurs here at all. You only, you only find them when you start digging for coal mines, which we weren't doing in.

• 3:08:22Lex Fridman?

  Is it basically a dramatization of like, of snakes and lizards and stuff like this?

• 3:08:27Speaker 01

  And just general exaggeration and welding stuff together. I mean, that's one thing you could put, I guess, potentially argue is that, you know, yeah, we find tyrannosaurs in North America and in East Asia. In fact, there's a whole bunch of stuff in the end Cretaceous, which is often very common because it's a relatively recent. In the grand scheme of things in the history of the world. The fauna of East Asia, China, Mongolia, Eastern Russia is very similar to what you get in Canada and the USA and down in Mexico. And so you find the same rough stuff. I mean, they're not exactly the same, but you get Ceratopsians, you get Tyrannosaurus, you get the Big Ash Dark Tyrannosaurus, you get Ankylosaurus, the armored ones, this, that and the other.

• 3:09:07Speaker 01

  So if these were influencing all those different cultures, why don't Chinese dragons look like Mexican dragons or equivalent of Thunderbirds or whatever? Well, because it probably wasn't influencing them. If they were all seeing the same skeleton, they'd probably all produce the same kind of mythical animals. They'll produce different ones.

• 3:09:25Lex Fridman?

  You have to understand paleontology is not perfect, so they were just misinterpreting.

• 3:09:28Speaker 01

  Misinterpreting, yeah.

• 3:09:29Lex Fridman?

  Yeah. I mean, dragons aside, I'm sure, like we said with weirdness, there would be creatures that would be remarkable, right? You look at it, you might as well be seeing a dragon. It could be. I mean, there's creatures alive in the sea today.

• 3:09:45Speaker 01

  Yeah, I mean, if you dredged up a colossal squid, I think you'd have.

• 3:09:49Lex Fridman?

  Yeah.

• 3:09:50Speaker 01

  You know, or even just dugongs and manatees. I mean, they're really quite strange.

• 3:09:55Lex Fridman?

  And if you allow yourself to marvel at the small things on Earth, like I was in the Amazon jungle, like the insects, they're just like, what is happening there? There's so many things going on.

• 3:10:07Speaker 01

  And there's.

• 3:10:08Lex Fridman?

  Ah, they're like hairy and colorful and probably poisonous and they have teeth and what? And they're long.

• 3:10:15Speaker 01

  And all the little weird eyes, I've, several times I've pitched a book to publishers where I want to write a book that basically makes the point that there is almost nothing. I mean, you can always dream up something totally ludicrous. There is basically nothing in science fiction that doesn't already exist on Earth in some way, shape or form.

• 3:10:35Lex Fridman?

  Yeah, that is why I often think about alien civilizations and aliens out there. And I'm very certain, very certain that there's aliens everywhere throughout the observable universe. It's very strange we haven't seen them, but it's. It's fun to marvel at what they possibly look like because there's a huge variety of organisms and species here on Earth and you just expand that out.

• 3:10:58Speaker 01

  Yeah.

• 3:10:58Lex Fridman?

  To like more and more Earths and you can just imagine there's a lot of weird.

• 3:11:04Speaker 01

  Well, that's the thing. I think most people, you know, understandably, I'm a biologist and I particularly pride myself on finding out about particularly weird animals. But yeah, I think people would be stunned about some of the weird stuff that's out there. That they just wouldn't realize a real, you know, things like velvet worms. You know, it's just blow your mind.

• 3:11:29Speaker 01

  You know, Sicilians and stuff like this and their reproductive behavior. It's just jaw drop. I mean, I love teaching about them. I do a class on diversity of life and I do about eight weeks of vertebrate diversity and I love just dropping things in and the students are like, what do you, what do you mean that exists? What do you mean something like that's normal for this group? Yeah, they do that.

• 3:11:51Lex Fridman?

  What from that, like that class, but everything you've studied with the dinosaurs? What have you learned about the evolution of life on Earth, that mechanism?

• 3:12:00Speaker 01

  It's it's really good. It's so, it sounds obvious, but it's, I think the bit that still fries my brain is just like the raw numbers because I think we're very bad at considering like I regularly talk about, oh, this is 70 million years old, but this is 78 and this is 104. And people are just like, oh my God, how on earth do you deal with those numbers? And I don't. They're just numbers because I can't conceive of it really any better than you can. They are astronomical. Yeah. Last Thursday was quite a long time ago. 66 million years is mind boggling. Like I, I, I can't fathom it.

• 3:12:44Speaker 01

  But that's it. I think the evolution thing is, A, my suspicion is quite a lot of it happens. It's not quite Steven Gould punctuated equilibrium, but I think stressful events probably prompt a lot more than less stressful events and other, you know, population crashes and all these things that then.

• 3:13:05Speaker 01

  Odd things survive and then that's changing your genetic component and all the rest of it. But you you've just got to remember that it's just, it's almost a numbers game.

• 3:13:15Speaker 01

  You know, it's that bad analogy of like, oh, evolution is just rolling dice and hoping you get all sixes. And it's like, no, a friend of mine said, no, it's rolling dice, but it gets to keep the sixes. And then suddenly getting a handful of sixes isn't that hard. But also you're in the context of even rare species, you know, ultra rare, I'm short of stuff that like we've nearly killed off. But like very rare species have populations in the thousands or hundreds of thousands. And are probably around for hundreds of thousands of years. And very few, you know, other than a few things like whales and apes and elephants, mostly have dozens or thousands of offspring at a time. So a few thousand animals that have a few thousand offspring at a line for a few hundred thousand years.

• 3:13:58Speaker 01

  Yeah, it's billions and billions and billions of them.

• 3:14:03Speaker 01

  And that's the rare stuff. You look at mola mola, the ocean sunfish, though I think, I think mola has just been split up into like five species. It's one of the weirdest looking animals. It's love it, love it, love it, love it. I mean, what a, what a fish that is. Swims with a giant dorsal and I think it's a giant anal fin and then they flap alternately.

• 3:14:23Lex Fridman?

  Does it have a face?

• 3:14:24Speaker 01

  Yeah. Yeah, yeah, yeah. Little one at the front, eat jellyfish. Super open oceanic and they get really big. You see that one with the diver. But I think these are the record breeders for animals and they have something like a hundred million eggs at a time.

• 3:14:38Lex Fridman?

  Whoa.

• 3:14:38Speaker 01

  Don't quote me on that, but it is something in those kinds of numbers. So yeah, that's, you don't need a very large population of sunfish to start having an awful lot of numbers. Are you going to Google it and see if you can find it? Uh, number of eggs or something, yeah. Three hundred million. Oh, I undercut.

• 3:14:59Lex Fridman?

  A single. A single female can release up to three hundred million eggs at one time during a spawning event. Boy. These eggs are incredibly small, measuring about one point three millimeters in diameter.

• 3:15:10Speaker 01

  That's still a lot of eggs though, when you think about it.

• 3:15:13Lex Fridman?

  It's not that small.

• 3:15:14Speaker 01

  Yeah, quite, like three hundred million of, of one mil is still quite a bit.

• 3:15:18Lex Fridman?

  Uh, fertilization is external. Females release their eggs into the water where males then fertilize them.

• 3:15:25Lex Fridman?

  Wow, man, there's a lot of different ways to have sex, I guess.

• 3:15:29Speaker 01

  Yeah, but, but, but, but that's, that's the bit of evolution that I think. I understand why people don't get it. We are mostly talking about millions in population times millions of years times thousands of offspring. Yeah, and it's kind of a numbers game. Well, how could this evolve? Well, the right selective pressure, and when you've got a hundred billion offspring, probably a few of them have.

• 3:15:55Lex Fridman?

  And when you focus in on a single species in trace its history, you can see how effective evolution is. Natural selection is, and then you just have to like go across species.

• 3:16:04Speaker 01

  Yeah, but, but it's also a massive compromise, which is the bit that people always miss. You know, it's Darwin's line, it's dissent with modification. Yes, over time, you can end up with extraordinarily weird things, but mostly what's happening is you're changing something fairly simple. You're, you're making edits to the existing plan, um, which is why you don't have animals with tentacles. They, they have legs which have joints which have fingers and they all have one bone, then two bones, then a bunch of little blocky bones and then a few more, and then the little ones that make up the digits for hands and feet. Basically, everything has that because you're modifying that pattern.

• 3:16:44Speaker 01

  And occasionally we had something weird like, um, most of the modern lungfish have basically reduced those down to, well, they, they had a more simple plan to begin with, but reduce it down to a stump and then they've got something like a flaily tentacle. But, yeah, you know, snakes have got rid of them or the various legless lizards and things like that. And again, Sicilians and, um, all the rest, but yeah, it, you're subtly changing certain things in certain ways is mostly what's going on. And then those build up over time, but also against that compromise of there's things that do and don't work. There's things that are interlinked and so you can't modify A without modifying B. Modifying A will kill you, therefore B never modifies because the two are genetically linked in some way.

• 3:17:29Speaker 01

  Or, yeah, like the compromise of the lion's mane, making it darker makes you sexier, but more likely to kill you. You, you, I think people think evolution is like perfecting things in some way and they're not, they're, they're bodge jobs. You know, that's why we have a blind spot in our eye, but. Things like squid don't.

• 3:17:50Lex Fridman?

  But that process nevertheless does have inventions in it. You have tectallic, you have a fish that learns to breathe, that crawls out.

• 3:17:57Speaker 01

  But it already had a swim bladder that it was probably processing a minimal amount of oxygen through and the swim bladder evolved for a certainly different function.

• 3:18:05Lex Fridman?

  Yeah, but that's one of the powerful things about evolution is switches the function. It develops it for one function, but once you, once you get there, you're like, okay, this could be used for another function. That, that leads to something that we in retrospect can see as a major invention, which is a fish that's able to crawl on land and all of a sudden we have, we have cities and rockets and yeah. Tectallic specifically, like there's something really mind boggling about a fish that crawls out of the sea. And you're just the image of that.

• 3:18:38Speaker 01

  Yeah, but again, you've got stuff that's not a million miles away from that. You have things like frogfish, which are fully marine, but kind of clamber through seaweed and stuff. And they've got pseudo functional limbs. So again, it's that

• 3:18:54Speaker 01

  tectallic is not weirdly derived frogfish, but it's not like it's a fish that suddenly came on land or a fish that suddenly evolved legs. There was already that selective pressure that was pushing it into a new opportunity, which gave it and

• 3:19:08Speaker 01

  and then on and on and on. And that's what keeps going. But it also brings up another thing, going back to dinosaurs and the behavior stuff, which again, I think has been a problem is the functionality thing and how there's always been, I think, this big perception of single traits having single functions, which isn't how a huge amount of biology works. For some, yeah, like eyes are used for seeing, they don't really do anything else. But I think there's a lot of, again, it comes down to a lot of the sexual selection stuff, but things like horns on triceratops. That's probably quite good for fighting off predators, but it's also quite good for fighting other triceratops. And then things like elephants dig with their tusks as well as fight other elephants, as well as fight lions, as well as stripping the bark off trees.

• 3:19:52Speaker 01

  So you've got to be very careful about how you think of functionality in two different ways. One way is what possible things could that thing do? And what possible things could have been the main selective pressure before? So you think about elephant tusks, as I say, they do all these different things, but when an elephant's just got. The tiniest little nubs, like the first elephant whose teeth are growing the wrong way and have pushed out of its jaw and now it's got a couple of little spikes. It can't really dig a hole with them. It's certainly not digging for water. They're probably not great against a predator because you'd basically have to get on your knees to try and lean over and try and stab it a bit.

• 3:20:35Speaker 01

  But you can show off to the girls and you can immediately fight another elephant who's head to head the same height as you and you've got a massive advantage. So evolutionarily, they probably started as some kind of sexually selected feature. But now functionally, they are probably compromised by the fact that having the best fighting tusks, but also having the tusks that are best at digging up water to keep you alive during a drought is putting selective pressure on that. And those are, although sexual selection appears in both ends, those are two different things. Digging for water is critical, but it's probably not what started it.

• 3:21:16Speaker 01

  And I think that's where we get trapped with things like, say, the paddle tail of spinosaurus or stuff like, or you know, or T. rex arms. It's like, well, why are T. rex arms like that? Well, maybe we need to consider what a slightly longer arm is like, or what it was being functioned for in its ancestors, or how it works in other species, or what else it might do, rather than every paper is like, did it do this, or did it do this, or did it do this? It's like, you know, it could be all of them? That's a very different question to try and answer, but people don't tend to think of it. And it ends up being very binary. And again, biology is not like that because it's a compromise.

• 3:21:52Lex Fridman?

  And it may be wiser to then look at the evolutionary origins, how it first sprung up.

• 3:21:56Speaker 01

  Yeah, if, yeah, you know, what, what does a miniaturized version of this look like and what might that function for, or how does it function in ancestral forms? You know, a really good example of that is giraffe necks, which have been argued about, you know, forever and a day, it was giraffe necks are to help them feed up high. And then in the late 90s, early 2000s, a couple of papers coming out going, actually, maybe it's sexual selection and competition. And then that drove down into arguments about, well, what does a short neck look like in the acarpi, its nearest relative, and what do short legs look like and how do they work? And plus a whole bunch of other studies. And ultimately it came out that we were right the first time. This is all about feeding. But it's a really interesting way of thinking about it and looking at it.

• 3:22:39Lex Fridman?

  Gotta ask you the ridiculous question. We do have dinosaurs here on earth today. They're birds.

• 3:22:46Speaker 01

  Yep, 10 and a half, 11,000 species of dinosaur.

• 3:22:49Lex Fridman?

  Are birds dinosaurs?

• 3:22:50Speaker 01

  Yes.

• 3:22:51Lex Fridman?

  Yeah, isn't that?

• 3:22:52Speaker 01

  It's just a yes. Yeah, it's.

• 3:22:55Lex Fridman?

  How many people know this, by the way?

• 3:22:56Speaker 01

  So there's, there's an interesting one. I did a radio show, oh, it's probably seven or eight years ago now. With a couple of, you know, drive time afternoon, nothing serious, nothing science or anything like that. And I mentioned something like this. And one presenter was, oh, my God, what do you mean, birds are dinosaurs? And the other one is, what do you mean, you don't know birds are dinosaurs? So it's hitting that tipping point of common knowledge. I think where. No, does, does, does everyone know? But no, but I think an awful lot of people know and are now kind of used to it as an idea.

• 3:23:28Lex Fridman?

  So what's evolutionary, the connection between birds and dinosaurs?

• 3:23:31Speaker 01

  I mean, they literally are in the same way that we are apes and mammals. Birds are dinosaurs. The direct, if you trace back the evolution of all the birds. So hummingbirds and albatross and ostrich and kiwi and parrots and pelicans and penguins and whatever else. And take them down to their ancestral point. And then go back quite a few more million years. Their nearest relatives to them is a dinosaur. It is actually something very close to velociraptor. Or at least a small version of velociraptor. So they, birds have literally descended from dinosaurs. Therefore they are dinosaurs. We have literally descended from other apes. We are apes. It is that. Form of evolutionary connection.

• 3:24:14Lex Fridman?

  Throughout that whole process, did they have feathers or did feathers come and go?

• 3:24:17Speaker 01

  So feathers are in tyrannosaurs. So feathers, feathers go back at least. So ironically. Cause the fossil record is very incomplete. Most of the things that are closest to birds. We know from the early and late Cretaceous. So the last kind of 50 million years of dinosaur evolution up to the extinction. And actually, birds almost certainly go back another 50 million years. So birds did not appear as a result of the dinosaurs going extinct. Birds lived alongside the dinosaurs for a hundred million years. This was, this is, the birds were not new on the scene and it's all like, oh, the dinosaurs dies and from the ashes rose the bird. No, they've been knocking around forever.

• 3:25:00Lex Fridman?

  They just survive because they're small.

• 3:25:01Speaker 01

  In a very large part, yeah, that's, that's almost certainly what really helped them. But birds took a kicking in the KT extinction. So did mammals. Loads of bird lineages went extinct and only a handful got over the line, but they did. But yeah, we have feathers in, as I said, we've got middle Jurassic tyrannosaurs that are 165 million years old, so 100 million years before the extinction, that have feathers. Simple feathers, they'd be like those you get on most baby chicks. So they're not with the big kind of classic pick up a feather in, you know, in the street or on a field of the, the big vein up the middle and then the kind of paired flat pieces. This would be much more like a hair,

• 3:25:41Speaker 01

  but we have them. We've got something which is very close to a bird, but might not quite be a bird with modern, but with modern feathers. In the middle Jurassic, we've got definitive stuff like archaeopteryx in the late Jurassic and then into the early Cretaceous, we have a series of fossil beds in China, which are just heaving with them. So yeah, and there's tyrannosaurs have feathers, velociraptor and the dromosaurus had feathers, trichodontids had feathers, ornithomimosaurs we've mentioned, they had feathers and so did a whole bunch of other groups as well. There's about eight or nine kind of major groups, kind of the size of something like, yeah, literally

• 3:26:20Speaker 01

  like carnivores or deers, you know, some massive groups, about eight or nine of them were fully feathered as far as we can tell. So feathers massively predate bird origins, but it was a major part of their evolution.

• 3:26:34Lex Fridman?

  Do I understand why feathers evolved with the function, the, the, the sexual selection, the signaling?

• 3:26:40Speaker 01

  Yeah, it's probably a fundamental twofold one, which is feathers insulate you, they keep you warm and most dinosaurs were. It's an archaic term, but it's what most people know warm blooded. So they were much more like us and birds. They had a stable, high body temperature regardless of the environmental conditions. And so if you're burning a lot of calories to stay warm, you wanna kind of keep that heat and feathers really help you do that. And then the other thing is, yeah, the obvious thing is sexual selection and communication. Feathers do stuff that scales can't. You can shed them in winter and change colour and come back as another one. That's quite a handy trick. You can change them between juveniles and adults. So baby birds have one type of feather, adults have a different one.

• 3:27:21Speaker 01

  We know of dinosaurs that do that. Well, we've got adults and juveniles with different feather types preserved in the fossils. Yeah, you can produce all kinds of weird colours and displays. You can erect feathers, you can hold them up and fan them out like a peacock or a pheasant. Whereas scales, you can't really do that a bit, or you need a huge amount of bone like Proterceratops. So there's two good reasons that they would probably evolve and exactly pulling them apart, or which is more important. And again, they're probably bi-functional. As soon as you start making feathers and making them more colourful, well, you're staying warmer, so that's an advantage. Or as soon as you start making feathers to make them warmer, it probably won't be long until someone evolves them to be a bit brighter red and then we're back to, oh my god, red!

• 3:28:03Speaker 01

  Right, but that's what's happening. And then they're probably gonna push each other potentially.

• 3:28:08Lex Fridman?

  I mean, it is true that the birds went real crazy with the feather and the colours and the prettiness and all that.

• 3:28:14Speaker 01

  They absolutely do.

• 3:28:15Lex Fridman?

  I mean, maybe there's something about feathers that allows for that efficient sort of diversification of fashion.

• 3:28:22Speaker 01

  Yeah, I think it gives them opportunities that scales and solid structures simply don't. I mean, the sole ability, I mean, I say like, you know, peacocks and pheasants, they are a massive disadvantage to males. They've got these extra plumes on them because they're so big and heavy. Peacocks can barely fly. But the fact is, you can still kind of fold them up into a fairly neat package and kind of hide if you really wanted to. Whereas if you're something like Triceratops, that billboard on the top of your head is not only enormous, but also bone. It's massive, it's heavy and you've got it on like around the whole year. Whereas peacocks at least can go, well, all the girls have settled down on their nests now. I'm just gonna get rid of all this extra weight and dump it.

• 3:29:05Lex Fridman?

  Just looking at the entire history of Earth, what has studying hundreds of millions of years of evolution, studying this epic age of the dinosaurs, what has that done for your appreciation of what makes Earth beautiful? Do you ever just like sit back and like, holy shit, this is incredible?

• 3:29:24Speaker 01

  Yeah, yeah, I do. But I guess maybe not much more so than I would anyway. As in, I already, because again, I don't really think of myself as a paleontologist in a lot of ways. Not that I don't love my work, but it's, I'm a biologist and this is what I'm looking at, but I'm fascinated and amazed by lungfish and flying frogs and caterpillars and onychopherans and butterflies and a million and one other hagfish and things that I think are cool and interesting and fascinating and I could happily read about them or watch them in

• 3:30:07Speaker 01

  a zoo or documentary or whatever it may be, almost every bit as much as I would with dinosaurs. I probably appreciate the dinosaurs and pterosaurs in a very different way because I have such a greater intimate knowledge of the science in a way that I try and read the lion literature because I'm really interested in predation dynamics, but I can't keep up with it whilst doing all the other stuff as well.

• 3:30:31Lex Fridman?

  Predation dynamics.

• 3:30:32Speaker 01

  Well, right, so like the difference of like what prey are they taking, why, at what percentage, what what influences, how are they competing with leopards and?

• 3:30:39Lex Fridman?

  Where there's a literature, body of literature on this?

• 3:30:42Speaker 01

  Yeah.

• 3:30:43Lex Fridman?

  All right.

• 3:30:43Speaker 01

  Yeah, people are studying lions and what they hunt and what they eat and where they do it, there's a, there's a whole bunch of stuff on particularly the, the African carnivores, because there's so many of them, they're so big and their populations aren't terrible compared to like South America or North America or, or a lot of Asia, for example.

• 3:31:03Speaker 01

  But yeah, going back to your question, yeah, I like, I appreciate all of it. It's all cool. Some of it is definitely more awesome than others. I work on some of the giant pterosaurs, the ones with 10 meter wingspans. Yeah, and it's, it's hard, like, uh, my partner's family's from Uganda and we was in, we were in Uganda last year. I was watching, Maribor stork circle overhead and you're like, wow, these things are huge and amazing. And then I'm like, their wingspan's about a fifth of the stuff I work on. Actually, these are quite pedally in the grand, you know, it's like an airliner going overhead. And when you think about it in that context, yeah, I mean,

• 3:31:46Speaker 01

  because, because that's it with the, you know, I know people tend to be obsessed with size and you kind of get it, like, blue whales are fundamentally cooler than smaller humpback whales, even if humpback whales are cool. Like, it's hard not to be impressed by Patagotitan or Tyrannosaurus or Triceratops or Quetzalcoatlus or any of these, like, ultimate giants. There's a reason we love great white sharks. There's a reason we love giant squid. There's a reason we love lions and grizzly bears and stuff, but the dinosaurs do kind of do it better than anyone else, or, you know, and the, you know, marine reptiles and the flying reptiles. It's just so insane.

• 3:32:20Lex Fridman?

  Yeah, both size and diversity.

• 3:32:22Speaker 01

  Yeah, and, and longevity as well. I mean, you, you look at, you know, elephants have come and gone and, you know, the whales, okay, the whales have reached superlative sizes, but they're relatively new on the scene.

• 3:32:35Speaker 01

  Could easily have gone extinct in the last century. But yeah, you know, there's truly Titanic dinosaurs for at least 100 million years.

• 3:32:44Lex Fridman?

  It's a long time. It's hard. Sometimes, as you said, it's very hard to load in just how long that is. They really dominated Earth for a very long time.

• 3:32:53Speaker 01

  And, and almost absolutely everywhere. There's a handful of places that we found where it appears that dinosaurs didn't really get in. Something else kind of took over, you know, like us, a bit like Australia with the marsupials versus the, the other eutherians. But yeah, fundamentally, it was a dinosaur planet for.

• 3:33:13Speaker 01

  After the Triassic less so, the end of the Triassic when they first get in going. But yeah, Jurassic and Cretaceous, yeah, it's 140 ish million years of yeah, just absolute dominance.

• 3:33:23Lex Fridman?

  I think it's hilarious and just perfect that there's a giant dinosaur head next to you and you didn't mention it once during this conversation.

• 3:33:31Speaker 01

  Yeah, so yeah, I thought we'd get, I mean, giant is an absolute ditty one. Yeah, so this is Protoceratops andrewsii and I've done loads of work on Protoceratops. It's from Mongolia. This is a latest size juvenile. So I've got a big head and the big head's kind of like this, but I really couldn't fit it in the bag.

• 3:33:48Lex Fridman?

  So this is to scale juvenile.

• 3:33:51Speaker 01

  This is not, this is not a, this is not original, but someone has molded and copied it. So it's not, it's not carved, it's a, it's a, it's a cast and a mold taken. So yeah, this is 100% accurate to the original specimen, or at least extraordinarily accurate to the original specimen.

• 3:34:07Lex Fridman?

  A young guy.

• 3:34:08Speaker 01

  Yeah, but yeah, I mean, at full size, it's going to be like pig or sheep size. So big, but not massive. But I've got it partly because it's affordable, because I can't afford to buy the big skeletons and skulls. But I've done a huge amount of work on it. And in part, and it goes back to those earlier conversations about populations. And if you really want to understand animals, you need an understanding of what a real population and a growth of what these animals looks like. And Protoceratops is, I would argue, probably the only dinosaur where we can really do that. Or at least as close as possible as you could get to any modern animal as an analog.

• 3:34:50Speaker 01

  We've got well over 100 good skeletons, though not probably only about 70 or 80 in really accessible museums. That's still a hell of a lot. We have everything from, here's a tiny baby on, this is a really cheap and nasty 3D print I had made. But that's a hatchling sized one or not much bigger than a hatchling sized one. All the way up to the big adults. We've now got embryos as well, which we didn't have until about 10 years ago. So we've got embryonic animals all the way up to big adults. They're all pretty much from one place in Mongolia. And they are, as far as we can tell, from a relatively narrow window in time, only about 100,000 years, which in the grand scheme of things is very close.

• 3:35:34Speaker 01

  So you've got one population from one place from one time with a hundred animals from embryos up to big adults. So now, if you want to look at, as I do, something like sexual selection and when does growth of the signal kick in and at what size and what evidence for dimorphism, well, suddenly you've got a population, you've got something you can work with. And that's why Procyx heretops is so important, and I think way more important than even a lot of my fellow paleontologists realise, and I genuinely think we should be pouring a lot more research into them, because they can tell us stuff that pretty much no other dinosaur can.

• 3:36:09Lex Fridman?

  Because they have the population data, so you can ask a lot more.

• 3:36:12Speaker 01

  And we can treat it as a population. So going way, way back to a conversation about telling males and females apart, and I said, big problem is population data, or at least the number of specimens that you have, when mostly you've only got one, two or three. I did a big study on this a few years ago, and Gary, yours, the really long-snouted crocodilians from Nepal and India and Pakistan with the giant bulge on the end of the nose. And even though the males are all bigger than the females, and the males all have this weird nose growth, though, that's mostly soft tissue, but they have a weird depression in the jaw, in the, in the end of the snout, where the nostrils sit. We got a sample size of something like about 110 animals, so these are very, very rare animals.

• 3:36:55Speaker 01

  So we had to ransack every museum worldwide. I was sending, my students were sending emails to huge numbers of people, have you got one sitting in your collection lost? Can you get it for us? Can you take these photos or these measurements? We can measure it. We put the dataset together, and then we found that actually, apart from the very biggest males, it's really hard to tell males and females apart. And this actually really closely matched some modelling data that I'd done with a colleague, Jordan Mallon in Ottawa, looking at this for alligators and, and trying to compare it to dinosaurs. Because though we talked about mutual sexual selection before, mutual sexual selection in particular, you tend to get things that are extremely similar.

• 3:37:39Speaker 01

  Males and females are very hard to tell apart. But there's also, there's a gradient, you know, all the way up to things like peacocks, all the way down to you can't tell them apart, like parrots. And for some features, when they take time to get growing, or because dinosaurs grow over a very long window and are sexually mature over a very long window, you run into the problem that a big female will look like a small male. And we can't sex them. And lo and behold, this is what you get with the garyals. The really big males are obvious because they're so much bigger and they've got this big depression in the in the snout. But medium sized and big females look like medium sized or smaller males and very small males.

• 3:38:23Speaker 01

  And so, yeah, that's basically what we have with dinosaurs, even with Protoceratops, where we've got a dataset of like a hundred. Papers have come out saying there's very mild sexual dimorphism, or there isn't sexual dimorphism.

• 3:38:40Speaker 01

  Sexual dimorphism could be very strong in Protoceratops, but we can't find it because we can't tell the males from the females. Because we haven't ID'd enough through something like medullary bone. And so you're in this horrible situation where, because going back to the T-Rex thing is like, well, maybe it's mutual sexual selection. And therefore they're cooperating and that would be cool. But also, maybe males are much bigger, but we can't tell because our dataset's too small.

• 3:39:07Lex Fridman?

  Oh, that's frustrating.

• 3:39:07Speaker 01

  In which case, they're not under mutual sexual selection and we've got it all wrong. Ah, it's maddening because it's so... If these were living animals, you'd just watch them or you'd just genotype them or you'd sex them and you'd just know. And and we just don't. But on the other hand, we do have the mechanism to do it. There are a handful of places where you get a bunch of Protoceratops together, where it's a mass mortality site. Well, let's go and drill every bone. Because if that's the breeding season, we might find seven or eight females and then the others are pretty much by default males. If we know it's the middle of the breeding season because all the others have medullary bone. And now you know where your male female split is. Now let's analyze those two data sets.

• 3:39:51Speaker 01

  And then maybe we'll see a difference and maybe we won't.

• 3:39:53Lex Fridman?

  Yeah, I love how that frustration is sort of a catalyst for figuring out. You're like searching for a place, a piece of evidence that just shows you clearly.

• 3:40:03Speaker 01

  There are ways in.

• 3:40:05Lex Fridman?

  Yeah, there's ways in.

• 3:40:06Speaker 01

  This is the thing. Yeah, there are there are ways in. And maybe we've got to get lucky because maybe it's not the breeding season. Or maybe that was just happened to be a group of all males and therefore we're not going to get the signal we're looking for. But there's enough of them and they're common enough. And yet, still digging in Mongolia, we keep finding new species, we keep finding new cooler stuff. But I'm like, can we dig up some more Protoceratops? Because actually, however cool these new things are, genuinely, if you want to know what dinosaurs are and how they worked, another hundred Protoceratops will actually probably tell us a lot more than 50 new species, however cool 50 new species might be.

• 3:40:47Lex Fridman?

  Paleontology is an incredible discipline. It really is Sherlock Holmes territory. So this was an incredible conversation. I'm really grateful for all the work you write, that you put out there. The podcast is incredible. I just thank you. Thank you for being you and thank you for talking today.

• 3:41:04Speaker 01

  Well, thank you very much for having me. I hope I haven't worn out my welcome with dinosaur story.

• 3:41:10Lex Fridman?

  We could talk for many more hours. Thank you, brother. Thank you, Dave.

• 3:41:13Speaker 01

  Thank you.

• 3:41:15Lex Fridman?

  Thank you for listening to this conversation with Dave Hohn. To support this podcast, please check out our sponsors in the description and consider subscribing to this channel. And now let me leave you with some words from Carl Sagan. Extinction is the rule. Survival is the exception. Thank you for listening. I hope to see you next time.