Short Wave - Why Do Flying Snakes Wiggle In The Air?

Episode Date: July 14, 2020

Some snakes can fly, and we don't mean on a plane. Certain snakes that live in South and Southeast Asia can leap off branches, undulating through the air, onto another tree. But why do they wiggle? NPR science correspondent Nell Greenfieldboyce shares one researcher's quest to find out.See 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

You're listening to Shortwave from NPR. Maddie Safaya here with NPR Science correspondent, Nell Greenfield Boys. Hey, Nell. Hey, Maddie. So, Nell, you have something both weird and amazing for us today, which I feel like is kind of right in your wheelhouse. All right. Well, I hope my repertoire is a little more expansive than that.

But I'll take weird and amazing. Yeah. So, you know how snakes kind of undulate or slither when they're moving around? Yes, serpentine, baby. Let's go. I like it. So this undulating is how they get around, like on the ground or in trees. And in fact, it turns out snakes that fly even do it when they're sailing in the air. Snakes on a plane. No, please.

I'm sorry, I just had to get one of it out and now we can focus. So, okay, seriously. Okay, all right. I'll give you one. Yes. But we're not talking that kind of flying. We're talking about, you know, flying snakes like that live in South and Southeast. Asia. You're aware of these snakes, right? Yes, I am very aware, but I don't know necessarily that our listeners are. So, yes, there are real snakes that can fly, which I feel like for some people is the stuff of nightmares. But to me, it's just amazing now.

I definitely have heard people say, like, do we really need to talk about flying snakes right now? It's 2020. Yeah, like, haven't things gotten bad enough? Like, can't the snake? This is just like, yeah, if you're not a snake person, this is a problem. But in the real world, these snakes exist, not to torment us, but to just live their lives. They cruise along the tree branches, you know, up hunting things up in the trees. And sometimes to get down to the ground or another tree, these snakes actually launch themselves into the air.

And they kind of glide down at an angle. The snake looks like it's swimming in the air. And when it's swimming, it's undulating. So that's Jake Soha, and he's a researcher at Virginia Tech. And he's been studying these snakes for nearly 25 years. And one of the things he's been wondering about is, like, why snakes do these movements in the air? Like, why do they undulate? And, you know, he thought maybe they're just doing it kind of like out of habit, you know?

Because like snakes, when they propel themselves, you know, on the ground or up a tree or in water, they do wiggle like this. Right, right. So it's not crazy to think that when the snake jumps into the air, the snake goes, hey, I'm a snake. I undulate, that's what I should be doing, I'm just going to undulate. Snake's got to undulate now. You know, that's what they do? Yeah, they're in the air and they're just like, ah, what do I do? I do, you know?

I snake. I snake. It seems plausible. On the other hand, it's possible that these motions actually might have a purpose. Like maybe they're doing something to help the snake fly through the air. So today on the show, one researcher's quest to find out how snakes fly. This is Shortwave, the Daily Science podcast from NPR. Okay, now, so this snake researcher, Jake Soha, is trying to figure out whether or not the way flying snakes undulate when they glide through the air is just like a matter of snake habit or whether it actually helps them fly.

Right. So how do you go about figuring this kind of thing out? Well, it's hard because their flights are really quite short, you know. And over the years, he's been trying to study them in different ways. You know, he's studied these snakes for a long time. And a few years ago, he was talking about them with someone that he had just met at, you know, Virginia Tech, where he works. And this guy said, maybe you'd be interested in the cube. And I was like, the cube?

What is the cube? Now, what is the cube? The cube is kind of just what it sounds like. It's a cube. A big theater space that is, you know, on the Virginia Tech campus. and it's this huge, empty room four stories high. And the important thing is it's equipped with all of these super expensive high-tech, high-speed cameras that are designed for motion capture.

And when I walked into this black box theater, I just looked around and went, oh, this is perfect. I so want to glide my snakes in this space. Okay. Okay, so he's going to let his Paradise Tree Snakes loose in this thing. Yeah, that's the idea. And so, as you can imagine, if you are at a university and they have a large theater space

and you want to let flying snakes loose in it, there's some steps you have to go through to convince everyone that this is a solid plan and that there will be no snakes showing up in people's offices later or, you know, obviously you don't want the snakes to get hurt. So, you know, it's like they didn't just, like, throw this thing together. It took some time. But once they got approval, Jake and his colleagues, you know, prepared the cube. And so they put foam padding down on the floor and, you know, they got this fake tree that they put up, you know, and they got this lift with this, you know, sort of tree branch on it that was going to be the leaping off point.

And then, you know, they prepared the snakes. Like emotionally? What do you mean? Well, you know, they did actually have to be. encouraging to the snakes. It's not like so easy to get the snakes to jump on cue. But that is not what I mean. I do not mean like sort of emotionally preparing the snakes for this moment in their lives. I mean like you know in Hollywood when they use motion capture technology to like take actors and convert them into animation or something. The actors wear these little reflective tags all over their bodies. Right like a little CGI setup situation kind of vibe.

Right. So that every movement can be. tracked and then, you know, that can be put into a computer. And so basically what they had to do is the same thing for snakes. So they had to figure out how to tag the snake's body in a way that would give them enough capture points while also letting the snakes move freely. And so they ended up putting around, you know, 11 to 17 bits of reflective tape all along the snake. So we essentially had nice resolution of the points in the body in the space, but we also had it in time. And our cameras were recording at almost 180 frames per second. And so that is fast enough that we got lots of representations of the snake as it went through

its full glide and it's doing its swimming-like behavior in the air. Okay. So basically they're using that reflective tape as a way to record the snake's movements as they flew through the cube. Right. They basically were able to capture how the snake's body was all moving. in three-dimensional space. And so basically what they would do is they would, you know, encourage the snake to jump off of its little perch towards this fake tree. And, you know, they did this dozens of times,

you know, filming dozens of glides over about two weeks. We now have the very first full representation of the snake's body in 3D space through the glide. And that basically means that they could finally see all kinds of subtle details that you You could never see if you were just standing on the ground, you know, watching a snake fly through the air. Yeah, this is very cool. Okay, so what did they learn from it? Well, one of the researchers, Isaac Yaten, he's now at the Johns Hopkins University Applied Physics Lab.

He told me that one thing they learned is that there's this kind of vertical wave that moves through the snake's body. And this was really strange, so we weren't expecting to see this. Usually snakes don't have a vertical wave. He says the only other example he was aware of is in sidewinder snakes that move across the sand. Have you ever seen those guys? Yes, yes. I'm a big fan of those. And so, you know, they found some other things like the way the snakes, the back of its body kind of bends up and down, seemed to have this quality that they hadn't appreciated before.

And so they had all this stuff, all these recordings with all these data points. And they basically took all of this information and used it to create a computer model. So they created like a kind of virtual snake. And then once you have this virtual snake, you can kind of explore what this motion does by turning off different aspects of the movement and then just watching in the simulations to see what that does to the flights. Wild. That is very cool. Okay, so what did they discover as they turned off little movements? So here's what Yaten says they found.

Snakes usually undulate for propulsion. So they're using it to push against their environment. But flying snakes are undulating for stability. Oh. So it makes their glides more stable. He says, you know, without these movements, a flying snake would either, you know, sort of start tumbling through the air or just plummet sooner.

Yeah. And so these undulations give the snake this sort of long, elegant glide through the air. Where they cover significant distance over the ground in a controlled manner. Okay, okay. this makes sense. So the snakes are out here snaken for stability, not just out of habit. That actually makes a lot of sense to me. Are there bigger implications here with this newly discovered flying snake knowledge? Like, it's enough for me now, but is there more to this? I know. With questions like this, I'm always just like, isn't this enough? Like, do we have to have, it is enough for me?

It's enough for me as well. I'm just happy to study, like, things in the world to learn about them. Like, I never feel like we need to have immediate applications. But everybody wants to know, why are you like, you know, throwing snakes? I mean, they're not throwing snakes. The snakes are jumping, but like, why put all this effort into studying snakes, like, flying through this theater? And I guess to me, it's basic research. And it's interesting to me to think about the snake body plan, which is very strange.

I mean, it's just this long cylinder with no limbs, you know. And the folks I talked with said that this has evolved independently several times. And, you know, so it seems to have real advantage. And snakes are able to use this in all kinds of different environments. I mean, just snakes live everywhere. They live in water and deserts, you know, and now think about the air, right? This is useful to them in the air. And so, you know, it's so different than the kind of locomotion that we're used to

and that we normally think about. And that's why scientists for years have explored this with robots. So the idea is, you know, you can make snake robots, partly because it's just cool and it helps them understand actual snakes at this basic level, but also, Also, you know, snake robots could go into all kinds of places that other body shapes couldn't. And, you know, I talked with Jennifer Reiser. She's a physicist at Georgia Tech who studied snake slithering, and she wasn't part of the research team. But she said the new findings are really cool and that, you know, their analysis could actually be used to make a snake robot that could glide through the air, maybe.

Wow. Flying snake robots now, what a time to be alive. You know what I mean? What a time to be alive. What a time to be alive. All right, now, great pill, boys. I appreciate you, and I appreciate this story. This is really fun.

Thank you, as always. This episode was produced by Britt Hansen and Rebecca Ramirez. Fact-checked by Britt Hansen and edited by Viet Le. I'm Maddie. Snakes on a Plain, Sophia. Thanks for listening to Shortwave from NPR. Whenever you face a choice, it helps to think like an economist. And this week on Planet Money Summer School,

we'll start off our course in economics with a workout for your brain. How to decide what something truly costs. Listen now to Planet Money from NPR.