How hurricanes triggered lizard evolution

Hurricane season is upon us and it turns out that these powerful storms can quickly affect the biology of animals. After hurricanes Irma and Maria hit the islands that make up Turks and Caicos about a decade ago, the silver key anole adapted. They now have a shorter fourth toe on their hind legs! That could help them cling to objects better. But how do you know unless you put lizards in front of a fan and record how long they can hold on? This study is out now in the journal Current Biology https://www.cell.com/current-biology/fulltext/S0960-9822(26)00887-0. Interested in more science in the news? Email us your question at [email protected] mailto:[email protected]. Support public media with NPR+ and enjoy perks for over 25 podcasts like this one. This show’s perks include sponsor-free listening. Learn more at plus.npr.org http://plus.npr.org. See pcm.adswizz.com https://pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. NPR Privacy Policy https://www.npr.org/about-npr/179878450/privacy-policy

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  This message comes from Planet Visionaries. Host Alex Honnold sits down this season with extraordinary doers creating real climate solutions. Listen or watch wherever you get your podcasts.

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  Hey, Short Wavers. Nate Rot here with my co-host, Gina B.

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  Hey, Nate.

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  We are back with our bi-weekly science news roundup with friend of the pod and West Coast Best Coast host of All Things Considered, Elsa Chang.

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  Hi, hi, hi. West Coast is the best coast.

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  West Coast Best Coast.

• 0:45Speaker 01

  I used to think that, but yes, for this small amount of time, I will think that again.

• 0:49Speaker 02

  Thank you, Gina. So Elsa, you remember the last time we gave you a kind of difficult science quiz?

• 0:54Speaker 01

  Yeah, I failed like every question. Well, was it every?

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  I've got great news.

• 0:58Speaker 01

  Yeah.

• 0:59Speaker 02

  We've got another one.

• 1:01Speaker 02

  But this time, hey, we're gonna make it easier. We're gonna make it multiple choice. And there's gonna be a fact that relates to each of the science news stories that we're covering today. You ready?

• 1:10Speaker 03

  I'm so ready.

• 1:11Speaker 02

  Okay, so our first topic is pretty relevant to this time of year. We're in hurricane season, right?

• 1:17Speaker 03

  Yeah.

• 1:17Speaker 02

  Started in June, usually lasts through November.

• 1:20Speaker 01

  And there are lizards in the Caribbean that have adapted to better survive those hurricanes.

• 1:25Speaker 03

  So weird, but okay.

• 1:27Speaker 01

  So this is my question. What is that kind of adaptation called? Is it A. climate resilience, B. reptilian progression, or C. rapid evolution?

• 1:39Speaker 03

  Ooh, climate resilience?

• 1:45Speaker 01

  It is rapid evolution. Okay, we got another one. We got another one. Keep going, keep going.

• 1:50Speaker 02

  Okay, so our second story is about verifying ancient artifacts, specifically pottery. But I'm wondering if you happen to know, Elsa, how old are the oldest pottery pieces archaeologists have ever discovered?

• 2:05Speaker 01

  Is it A. thousands of years old, B. tens of thousands of years old, or C. only a couple hundred years old?

• 2:14Speaker 03

  Okay, I know it's not C. It's between A and B. How long have humans been around? I'm gonna just say thousands of years old. That's A.

• 2:23Speaker 02

  You were doing so good.

• 2:24Speaker 01

  You were so close. You were so close. Tens of thousands. But you're processing a little nation. We're getting closer.

• 2:31Speaker 02

  Okay, so our last story is not one to make light of because it's actually kind of serious. It's about the effects of extreme heat on the human body. Which of these following conditions make it more likely for someone to get heat stroke? Is it A. lightning strikes, B. a high UV index, or C. increased humidity?

• 2:50Speaker 03

  Ooh, well, it's not A. lightning strikes. It's either higher UV or higher humidity. But I'm gonna, I'm gonna go with higher UV.

• 3:00Speaker 01

  Elsa, you're so close.

• 3:03Speaker 02

  We want you to succeed. We really do.

• 3:05Speaker 01

  Humidity is a really important factor in heat stroke risk because if it's so humid that your sweat can't evaporate off your skin, then it's pretty easy for the human body to overheat.

• 3:17Speaker 03

  So in my brain, I was thinking higher humidity would help me dehydrate less. But you're telling me it makes you dehydrate more?

• 3:25Speaker 01

  Yes. Yeah, it's pretty bad.

• 3:28Speaker 01

  We learn from our failures.

• 3:29Speaker 02

  Well, let's take that failure and let's launch into the success of the rest of this show. We've got lizards that survive hurricanes.

• 3:36Speaker 01

  Plus a new method of dating ancient pottery.

• 3:39Speaker 03

  Not dating like going on a date with them, but like telling people how old they are.

• 3:42Speaker 01

  Right, right.

• 3:43Speaker 03

  At this point, I'll try anything.

• 3:47Speaker 01

  And we'll talk about some surprising health issues that could be linked to extreme heat.

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  You're listening to Short Wave, the science podcast from NPR.

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• 5:20Speaker 01

  Okay, Elsa, I'm gonna start us off with lizards.

• 5:23Speaker 03

  Okay, you mentioned that they were evolving because of hurricanes? What?

• 5:28Speaker 01

  Yes. So this story is set on these two islands in the Caribbean. These islands were walloped by hurricanes Irma and Maria about a decade ago. And researchers wanted to understand how these hurricanes might have affected populations of lizards that live there. They're called silver key annoles.

• 5:45Speaker 02

  And in particular, they wanted to know why the surviving lizards from these hurricanes seem to have shorter fourth toes on their hind feet.

• 5:53Speaker 03

  Shorter toes on their hind feet. What's up?

• 5:57Speaker 02

  Well, the researchers think that these shorter toes might have given the lizards a selective advantage during these hurricanes, where they endured these incredibly strong winds.

• 6:05Speaker 01

  Yeah, it's physics. It turns out the shorter toe gives the lizard more leverage to hold on to the branch better than a longer toe. And at Princeton University, evolutionary biologists tested this out. They put lizards in front of a fan to simulate tropical storm force winds.

• 6:20Speaker 03

  Oh, my God, poor lizards.

• 6:24Speaker 02

  Yeah, we asked one of the researchers, Shane Campbell-Staiton, if the lizards seem annoyed by this?

• 6:29Speaker 05

  They are as annoyed as you would expect from, you know, somebody blowing a bunch of wind in your face. You know, but the trials themselves are actually very short. A net catches them.

• 6:42Speaker 02

  So the lizards were totally fine. And it turns out that the lizards with the shorter toe were able to cling on for a half a minute longer than ones with longer toes.

• 6:51Speaker 01

  But what's really cool about this study is that researchers were able to confirm a specific gene that was linked to making these toes shorter, like showing that these hurricane-force winds likely shaped the genes of subsequent, like, generations of these lizards, something they wrote about recently in the journal Current Biology.

• 7:08Speaker 03

  Wait, so like, why did these scientists even get obsessed in the first place about the toes of these lizards?

• 7:13Speaker 02

  Well, so by teasing apart all the genes at play here in follow-up research, they're hoping that it'll give geneticists a deeper understanding into how, you know, multiple genes interact with each other and the environment to drive changes in animals. And it could help researchers understand how other animals might be able to adapt to rapid changes in the future.

• 7:32Speaker 03

  Ah, okay. All right. From lizards to artifacts?

• 7:36Speaker 01

  Yeah.

• 7:37Speaker 03

  Let's go.

• 7:38Speaker 01

  Yeah.

• 7:39Speaker 02

  Okay, so this study is looking specifically at clay artifacts, like pottery figurines, which, Elsa, if you've ever been to a museum, you know, they hold a pretty important significance in human history.

• 7:50Speaker 01

  Yep. And one of the issues that museums and law enforcement agencies face today is that people will sometimes sell forged or fake clay antiquities.

• 7:59Speaker 03

  Yeah, like they'll claim a piece of pottery or some figurine is thousands of years old when it's totally not.

• 8:05Speaker 01

  Yeah, exactly, Elsa. And to be clear, this isn't new.

• 8:08Speaker 06

  There was fraud of statues already in the Roman period, so it's something that goes back a long time.

• 8:14Speaker 02

  That's Juave Vaknin. He's a postdoctoral student at the Scripps Institution of Oceanography and the lead author of this new study, which describes a new way to determine whether something is legit or not.

• 8:24Speaker 03

  Interesting. Okay, tell us how this works.

• 8:27Speaker 02

  Magnetism, Elsa.

• 8:28Speaker 01

  It's physics again.

• 8:29Speaker 02

  Yeah. So when you take a piece of raw clay and you put it in a kiln, the iron-bearing minerals in that clay will align with the Earth's magnetic field.

• 8:38Speaker 03

  Whoa.

• 8:38Speaker 06

  Kind of like you can imagine a needle of a compass, but on the atomic level.

• 8:42Speaker 01

  And when that clay starts to cool, the larger particles get locked into that position, creating kind of a permanent record of the Earth's magnetic field at that moment.

• 8:51Speaker 03

  Wow. So it's like unique to that particular time and place on Earth? And scientists can use that data to date the pottery?

• 8:59Speaker 01

  Unfortunately, no, because the objects have moved from their original position. But there are these smaller particles that don't get locked into position, and their magnetic signatures never really settle. So they move with the Earth's magnetic field over time.

• 9:13Speaker 02

  Yeah, and the secondary magnetic signal can be erased by reheating the object. And what Yoav and his colleagues discovered is that it takes hotter temperatures to erase it in old objects than it does in new.

• 9:26Speaker 03

  Huh. Okay, so you could theoretically test to see if an object is old or authentic versus new and forged just by reheating it?

• 9:35Speaker 02

  Yeah, they tested old artifacts, and they found that if it takes above 112 degrees Celsius to erase that secondary magnetism, the object is indeed more than 1,000 years old. Now, I will say, Elsa, you need very specialized equipment to do this, but the method described in the Proceedings of the National Academy of Sciences could be used by museum curators or others to determine if artifacts are indeed legit in the future.

• 9:58Speaker 03

  Well, speaking of heating or reheating, let's get to our final topic. Let's talk about these health issues linked to extreme heat.

• 10:06Speaker 01

  Yeah, more on the serious news here. We know that climate change is linked to more frequent and more severe heat waves, but we still don't know the full impacts of those heat waves on human health. So researchers in Chicago analyzed almost a million ER and urgent care visits over the past 12 years. And they did this to find which diagnoses were correlated with periods of extreme heat in the city. Basically, going in without a preliminary idea of what they're looking for, just running through the data and looking for patterns.

• 10:34Speaker 02

  Yeah, and what they found wasn't just like your typical culprits from heat, like dehydration or heat stroke. Really hot days were also associated with things like higher diagnoses of kidney failure, of skin rashes, of swelling, of mental and behavioral disorders, assault, and Elsa, even traffic accidents.

• 10:51Speaker 03

  I mean, I feel like that kind of makes sense, because when it's really hot, people kind of go out of their minds, yeah?

• 10:58Speaker 02

  I mean, yeah, totally. So like, researchers told us that like, some of these more mental and behavior-related diagnoses, they might be due to heat stress. Like, let's listen to one of the researchers on this project.

• 11:09Speaker 07

  We do know from prior literature that when it's hot out, people are under a lot of stress, mental physiologic stress. People are out more, and behaviors change.

• 11:20Speaker 01

  So that's Dr. Abel Ko. He lives in Chicago, where he's a professor of medicine at Northwestern University, as well as a practicing physician. And he was part of the team that did this research. They recently published a paper with these findings in the journal Science Advances.

• 11:34Speaker 03

  Okay, got it. So now that they've found these associations, what do you do with them?

• 11:39Speaker 01

  So Abel and the other experts we talked to said it's important to note that these are looking at associations, not causality. Maybe that's the next step, like figuring out why extreme heat might exacerbate these health issues and how to deal with it.

• 11:52Speaker 02

  And Elsa, I want to just plug really quick. Speaking of extreme heat studies, NPR climate correspondent Alejandro Barunda has been working on a huge project with Boston University scientists to investigate undercounted heat-related deaths across the country. And it's really enlightening. So you can search for your county and track the number of heat-related deaths near you on the NPR website. We'll link to it in the show notes. I highly encourage people to go check it out.

• 12:15Speaker 01

  I'm gonna check it out.

• 12:16Speaker 03

  Yeah.

• 12:17Speaker 02

  Well, Elsa, thank you, as always,

• 12:20Speaker 01

  Of course.

• 12:20Speaker 02

  for kicking it with Short Wave. You're the best.

• 12:22Speaker 03

  You guys are so much fun, even when you humiliate me.

• 12:25Speaker 01

  No. Thank you for coming.

• 12:29Speaker 02

  So if you, like me, love having as much Elsa in your life as possible, check out Consider This, NPR's afternoon podcast about what the news means for you. This episode was produced by Hannah Chin and Mark Rivers. It was edited by Rebecca Ramirez and Christopher Intagliata.

• 12:47Speaker 01

  Tyler Jones checked the facts. Jimmy Keely and A. Owen Fain were the audio engineers. I'm Regina Barber.

• 12:52Speaker 02

  And I'm Nate Rott. Thanks for listening to Short Wave, the science podcast from NPR.

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