Science Friday
Hosted by Ira Flatow
The nature documentary series uses new research and photorealistic CGI to bring the huge, bizarre animals of the Ice Age back to life.
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Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.
Hey, it's Ira Flatow and you're listening to Science Friday. Koalas with the body of a lion, elephants the size of your dog, gigantic eight-foot-tall sloths. No, these aren't creatures found in a new novel. They walked our planet a million years ago during the Ice Age. And that's the focus of the new season of Apple's Prehistoric Planet series, which uses the latest paleontology research and photo real CGI to recreate ancient creatures from the past. So far, it's focused on dinosaurs. But now it's taking that same approach to the fantastical and strange-looking animals
that walked the tundra and enormous deserts of the Ice Age. Here to thaw out the new research featured in the show are two of its scientific consultants, Dr. Darren Nash, paleontologist and author in Southampton, UK, and Dr. Emily Lindsay, associate curator at the La Brea Tar Pits and Museum in Los Angeles, one of my favorite places. Welcome back to Science Friday.
Thanks for having us.
Thanks. Good to talk to you again.
Darren, we had you on the show a couple of years ago to talk about the science in the first season of this show, which, as I said before, focused on dinosaurs. What were you excited about with this season going into the Ice Age? What did you want to do differently?
That's a great question and a hard one to answer. As a fan of animals in general, you know, when I knew that we were going to be making an Ice Age series, even the Ice Age animals that are the most household names of these creatures that you can think of, you know, woolly mammoths. Who hasn't heard of a woolly mammoth? That's not an unfamiliar animal. You know, most of us have kind of grown up with exposure to, you know, the fact that there were such animals. But that doesn't kind of, you know, mean that there aren't amazing things to learn about it. Like, what does it actually look like in life and how does it behave? So I knew that even building, you know, the super-familiar animals...
The woolly mammoth, various of the species of saber-toothed cats, you know, just building those familiar animals was going to be a formidable challenge. It was going to be really great fun. We were going to learn a lot from it. And because mammoths are elephants, because saber-toothed cats are cats, these animals actually present a real special challenge in terms of bringing them to life, something that, you know, obviously we had to work incredibly closely with the the CG animators at Frame Store because the familiarity of those animals in fact makes them even harder to reconstruct accurately and realistically than animals that are actually pretty remote to us today. You know, if you're talking about a tyrannosaur, like very few people today have got a real good idea of how a tyrannosaur might look as a living animal. But if it's a cat,
you get that slightly wrong and immediately it just doesn't pass the sniff test. So building those animals, I knew that was going to be tremendous, a challenge and fun. And then there's all these obscure creatures, these less familiar, very extinct weirdos relative to the sort of northern hemisphere perspective, animals like the giant marsupials from Australia, various extinct animals from tropical Africa and South America. Um, you know, various weird obscure sloths, various giant marsupials, giant short-faced kangaroos could not wait to get to grips with those because experts have competing ideas on what they look like, how they moved, how they behaved,
how we would actually bring that together and build them. I knew that would be a fun challenge and the results speak for themselves. I'm super happy with how all our animals look.
Emily, do you find evidence in the La Brea tar pits of ancient animals?
Oh, yes, we have thousands upon thousands of animals from the Ice Age that are preserved in the tar pits here in Los Angeles. Interestingly, Los Angeles was actually a little bit cooler and a little wetter than it is today. So it was really a lush kind of savanna ecosystem supporting, you know, multiple species of giant ground sloths. We have seven species of cats here, all the way from the American lion, which is the largest cat that ever lived. Multiple species of saber-toothed cats. We have famously dire wolves, which are our most common large mammal we find preserved here, mammoths and mastodons, camels and horses and bison. It was an incredibly rich ecosystem.
Of Ice Age LA. But as Darren mentioned, we also have hundreds of species of birds and reptiles and amphibians and mammals that are still alive today, and many of which still live here in the LA basin.
Okay, so the season opens with a bang, with a woolly mammoth giving birth to a baby in a brutal snowstorm. What did it take to survive as an animal during this time?
Um, the, one of the key things about the Ice Age world, so the Ice Age is properly known as the Pleistocene, it's about a 2 million year long section of geological time, is famously, we are talking about a time when the, the far north and the far south of the, of our planet is colder than it is today. There are much larger ice sheets, obviously colder, colder temperatures, but you are still talking about a world that does have tropical and subtropical and temperate zones as well. And a key thing that we cover in the series is that with all of this vast amount of, of water locked up in ice, it meant less kind of atmospheric water across the whole of the planet, which means, you
know, lower sea levels and a far drier atmosphere. So things like savannas and deserts were larger during the Ice Age than they are today. So, so yes, you've got these animals that are adapted for extreme cold and in multiple different lineages, in particular of, of big mammals in particular, you saw, you know, animals with extra layers of fat and thick woolly coats and so on, among groups that today we associate with the tropics, you know, mammoths are not a separate group of animals from elephants, they are a kind of elephant. So, you know, you've got cold adapted elephants, likewise for big cats, cold adapted cats, cold adapted, you know, deer and bear and, and so on. But then in
the, in the tropics, you've got many animals that are more adapted for dry climates. So animals with unusual noses because they are doing what they can to conserve water. And the final thing I have to add, an important point about Ice Age animals is the Ice Age is so recent, it ended about 11,700 years ago, that's really recent. Everything alive today, with a handful of exceptions, a handful of, you know, very recently evolved animals, weird salamanders and such, everything alive today was alive in the Ice Age, including us. So you've still got to imagine that everything alive today is also present in Ice Age times.
I've also heard that the VFX team referenced cave paintings to get the fur right on the animals. Is that correct?
That's basically right. So we are Ice Age animals. We saw a lot of these animals when we were alive and people of the Ice Age, some of whom were incredibly skilled and experienced artists, illustrated a lot of these animals when they were alive. And in some cases, they provided us with information that we otherwise wouldn't know. So the main thing that they gave us is patterns of pigmentation. So on some animals, there's various extinct deer and cats, mammoths and rhinos also, where the cave artists showed precise distributions of spots and stripes, gave us some idea which parts of animals were dark, which were light,
what fur length was like. And even there's even some clues to posture, you know, like when does a woolly rhino have its tail in the air, stuff like that? So yes, we took account of all of that and built it into our models as well.
Darren, you know, we obviously think of the ice and snow during the Ice Age. That's we call it the Ice Age. But the show spends a lot of time in deserts, in tropical regions. What were those like?
Yeah, so the fact that the Ice Age goes from round about 2.6 million years ago until round about 11,700 years ago, that's enough time for a lot of change to happen. We also know, we've known for centuries that this span of time that we term the Ice Age actually consists of multiple very cold spells and then very warm spells. And during the interglacials, the warm spells, you've got to imagine that somewhere today that we consider fairly, you know, cool and temperate, might actually have been a little bit You know, warmer, drier. Um, I'm obviously in southern England and during some of the interglacials,
there were animals here that today we think of as animals of tropical Asia, the Middle East, uh, you know, parts of Africa. So there were giant elephants here and there were hippos and there were lions. There were lions of a kind of tropical sort uh here in England. So um from our perspective today, a a completely different world. So it's a a super interesting world, a really more diverse world. And the key take home point for me about the Ice Age is in a way, the diversity of animal life in the Ice Age is kind of what our planet's meant to be like. When we think of giant animals today, if you're in North America, you're thinking of you've got moose
and you've got, you know, two big bear species, a couple of other big deer and and whatnot and bison, obviously. But alongside those, you know, there should be armadillos the size of small cars, sloths bigger than the biggest bear. There should be several species of elephant living wild in in North America. And and I can say similar things, you know, everywhere, everywhere in the world, except Antarctica. All the major land masses had this amazing assortment of animals that are no no longer with us at all. So we've we've got a very impoverished view of mega faunal diversity. Mega fauna is anything above about forty kilos.
That that raises the question, if you found the same species on completely different continents, how did that happen?
Yeah. So um many animals that today we associate with a specific region in the Ice Age were able to spread widely around the world. The the lions are a great example. You know, we mostly think of lions as as an African animal. There were also lions in the, you know, in the Middle East. But in the Ice Age, there were lions throughout the whole of Asia, throughout the whole of Europe, throughout North America, and some lions probably got into South America as well. This is partly due to the appearance of land bridges. So if sea level is going up and down according to how much water is locked up in ice, lower sea levels mean that areas of land that today are separated by sea were connected during the Ice Age. So the the most fami- familiar
example is Beringia, which is the area that contacts Alaska with Siberia. If that's dry land, animals can obviously pass relatively freely between North America and Asia.
Hmm.
Yeah, I I wanna add to that, um, actually to to both of Darren's points. So I I completely agree with the Point that we have an impoverished view of an understanding of megafaunal diversity from the present day. You know, 50 plus million years, the normal state for planet Earth has been to have large animals, chiefly mammals, on all the ice-free continents on Earth. And it's only very, very recently in geologic time that that hasn't been the case. And these migrations, you know, I mean, they started happening millions of years ago. So a lot of species that we actually associate with other places, maybe Africa or Asia or South America, actually started out in North America.
So camels would be one of the key examples here. You know, in North America, we tend to think of camels as very exotic animals, but they actually evolved here in North America. Really? Yes. And then, you know, 10 or 15 million years ago, they crossed a land bridge into Eurasia and became modern camels. 3 million years ago, the Smits of Panama formed. They crossed down into South America and became llamas. And then they went extinct here in North America at the end of the Ice Age. And so what you see happening during the extinction event at the end of the Ice Age that wiped out more than two thirds of the large mammals on Earth is a real range contraction of species that, as Darren mentioned, used to be really widely distributed.
Lions, camels, horses, elephants. And now they're only associated usually with, you know, one continent or one particular geographic region.
We have to take a quick break, but don't go away. More on this when we come back.
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Let me ask you a bit about that, because I know you study how ecosystems collapse. How did the Ice Age end?
Well, so that's something that scientists have been debating for more than 70 years now, and it's still a point of contention. But I think, you know, if you take a zoomed-out view of it, the story of the last 50,000 years or so is the story of one megafaunal species, Homo sapiens, sort of systematically replacing most other large mammal species on Earth. So, humans were definitely a key player in this extinction event on a sort of broad-brush scale. Now, I think the question is, like, how did we do it, right? And I
think the show does a good job of communicating the stresses that animal populations experienced due to these very significant climate changes that were happening. And so, how did sort of climate and environmental change intersect with sort of growing human population and technology and resource consumption to cause this sort of ecosystem global tipping point where we go from, you know, the age of mammals to really the age of humans?
Are you saying that we hunted these large animals out of existence?
I think it's more complicated than that. You know, when scientists talk about humans being responsible for the extinction, they're usually thinking about hunting. But I don't think that Homo sapiens hunted down, you know, every species, dozens and dozens of species when extinct at the end of the Ice Age. We do have good evidence of humans hunting, in some cases on large scale, particular species, different types of elephant species, right? Mammoths, we know they hunted horses and camels. There are other species that we have absolutely zero evidence of humans hunting. So I think there's a combination of of hunting and and other impacts.
And something that we discovered here, based on research at the La Brea Tar Pits that we conducted a couple of years ago, is that, at least in this region, there's a particular tool that humans were able to use to completely transform the ecosystem, and that was fire. And we discovered that, right at the point when large animals stopped getting trapped at the La Brea Tar Pits, there is this order of magnitude increase in fire on the landscape, and those fires were very likely ignited by humans.
So, where are we in our general understanding of the Ice Age now? You mentioned new research that you've discovered at La Brea Tar Pits. But in general, compared to past decades, what do we know more now than we knew years ago?
In many ways, this is the golden age of Ice Age studies for a bunch of reasons. It was the perfect time to make a TV series devoted to these animals and their world, because there's so much amazing and new science that's being done on them. So, for example, DNA studies, you know, there's this new information that's helping us work out how these animals are related to one another, and even aspects of their their life appearance, some of their adaptations to the cold we've learned about, thanks to, you know, recent genetic discoveries. We know, for example, that woolly mammoths actually lacked a specific Genes that are related to feeling cold and they actually had like they were genetically
adapted for being okay in the cold and a slightly sad subject but a global warming that we are causing is resulting in the increasing discovery of Ice Age animals in Siberian and Alaskan permafrost. So we are finding year on year more permafrost bodies, you know, nearly complete, beautifully preserved Ice Age animals that give us, you know, like so much information on what the animals actually looked like. This is, this is a great time to make a TV series about these incredible animals.
Well, I want to thank both of you for taking time to be with us today. Fascinating stuff. Dr. Darren Nash, paleontologist and author, and Dr. Emily Lindsay, Associate Curator and Excavation Site Director at the La Brea Tar Pits and Museum. You can catch the new season of Prehistoric Planet on Apple TV. This episode was produced by Dee Peterschmidt. I'm Ira Flatow. Thanks for listening.
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