Short Wave - Flamingos: The Water-Bending Physics Masters

Episode Date: May 23, 2025

Riddle us this: Which animal is pink, curved beaked and a master of the physics required to create water tornadoes? If you guessed flamingos, you're right. New research out this month in the journal Proceedings of the National Academy of Sciences shows that across a range of harsh environments, flamingos have become masters — of physics, fluid dynamics and so much more — all in pursuit of their filter-fed prey. Short Wave host Regina G. Barber sits down with biomechanics researcher Victor Ortega Jiménez to hear all of the incredibly involved lengths these birds go through to get their prey. Want to hear about more physics or animal discoveries? Email us at [e-mail] to tell us what areas of science you'd be interested in.Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.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. Hey, shortwavers, Emily Kwong here with my co-host and our resident physicist Regina Barber. Hey, Gina. Hey, I have a really important physics question for you. Okay. What? Okay. Do you like flamingos?

I love all birds, but flamingos are among the weirdest and the coolest. I think so. What does that have to do with physics? I'm going to show you a video of one feeding now. Okay. Go ahead and pull it up. Oh, this is cute. Okay, so yes, we have this classic pink leggy flamingo.

Yeah, he's eating by dipping his head in the water. Yeah, he's got this curve beak at the end of his long neck and this large tongue. And I guess I didn't know they did this. He's stomping his feet in the water too, like pep, pep, pep, pep, pep, yeah. And you'll notice his head is like upside down, like his eyes are going in first into the water. Yeah. And this pretty unusual feeding behavior, like caught the eye of Victor Ortega Jimenez. And he studies biomechanics.

Oh, so he studies how living things move. Yes, correct. So back in 2019 during a trip to the Atlanta Zoo, Victor saw the flamingos feeding, like opening and closing their beats like really, really, really quickly. And this is called chattering. And in the animal kingdom, this is like really bizarre. Like animals don't really do all this. So as a scientist, Victor was like, why? Like how?

The mystery of these magnificent birds, what are they doing inside of the fluid? And because I'm a biologist, the interesting part of knowing what? is the interaction between the animal with the environment, in this case, the fluid, to me was very attractive. Okay. This is a fluid dynamic story, isn't it? Yes. That's the physics part.

Yes. And this question of like what's happening to the water with all this flamingo movement started years of research. It involved watching live flamingos, 3D printing flamingo beaks and feet. Nice. And M. Victor and his team just recently published all their findings in the journal Proceedings of the National Academy of Sciences. And what they found surprised them.

So much of this feeding behavior, the stomping, the beak chattering, the upside down heads, sometimes like skimming the water, and sometimes dipping in and out, it was all in pursuit of one thing. What's that? Water vortexes. Oh, like whirlpools. Basically, like, they're swirling the water to hunt. Flamingos are predators? Yes, it blew my mind, too.

They're making water tornadoes to get shrimp and other food into their beak. That's cool. We observed that they were producing some tornado-like vortices. And we know tornadoes can be destructive, that they are very effective to lift particles from the ground or from the bottom, in this case of sediments. Say on the show, nature's waterbenders. We get into how flamingos control the water around them

with their unique fashionable looks and dances, and why all of this adds up to more success in harsher environments. You're listening to Shortwave, the science podcast from NPR. Okay, Gina, let's talk about flamingos. I understand flamingos, okay, they eat in this really odd way, and they're feeding in really salty, muddy waters where there isn't really any fish. Like, what's up with their eating behavior? Yeah, so flamingos roam in these, like, huge flocks around like 70 birds on average, but they can get up to like over 300. And they need lots and lots of food.

And they're filter feeders, meaning they eat by filtering water through a mesh in their mouth. Oh, so they're like whales. Yeah, yeah, that's what I thought, too. But also, like, some ducks and swans do this. And the prey of choice for flamingos are algae, tiny brine shrimp, fly larvae, like other tiny things that, like, fish also eat. So flamingos go to these places that have little or no fish so that there's more food available, like less competition. Oh, so that's why they flock to these harsher waters. Yeah, and be that salty, muddy waters or really, really hot waters.

Here's Victor Ortega Jimenez again. And actually, some of the flamingos also can live in springs. The temperatures are at the point of boiling water. What? So, and yeah, so flamingos are just these extreme animals that lives in this environment. Flamingos are eating out of the hot tub. Yeah, nature. Like, this whole story, like, I was getting so much new information.

But let's go back. Okay. Let's go back to that day at the Atlanta Zoo, Victor saw like feeding flamingos making tornadoes in the water. Like this prompted him to run home and start looking through scientific papers. And he realized there wasn't a lot out there. Like there's very little research on flamingos eating behaviors. It was mostly like descriptions of what they look like.

And the research seemed to be really focused on flamingo's tongues. These researchers writing these papers thought that the main driver of getting the food into the beak was the tongue, like a piston, bringing water in and out. But Victor had a hunch that the tongue, like it was. tongue. Like, it wasn't the whole story. There had to be more. Like, it can't all be the tongue. Like, why are the flamingos dipping their head upside down, like, feeding upside down, like, in the water? Yeah. And, like, why are they stomping their feet? Right, right. Why do they march? And, like, why do they chatter their beaks and, like, opening and closing it 12 times a second? Wow. That's a lot. Yeah. It's very, very fast. And all of these things are all happening at once. And Victor and his team had to

break the whole process down. Like, so they looked at four different. different behaviors individually. All right. Walk us through. Which behaviors did he focus on? Okay. So let's first talk about chattering, which in this study is just like flamingos rapidly opening and closing their beaks to really drill down on this more.

Victor and his team went to the Nashville Zoo to get footage of flamingos eating so that they could bring that footage back to their lap and compare that natural eating footage to experiments they ran with like two sets of beaks. And one set of beaks were 3D printed. And the other set was from deceased flamingos donated after death. by the Atlanta Zoo. What were they trying to figure out? They were trying to figure out, like, what is this chattering doing?

Our question was, what is producing that direction of flow? Is the tongue or it's just the chattering? And what the surprise is that we observe that direction of flow without the tongue. So it's not making the water spin. No, the tongue isn't really making that water spin. It's really the beak itself, chattering. And it's also dependent on this, like, unique shape of the beak. Oh, yeah, because I guess flamingo beaks are curved, right?

Yeah, more specifically, like they're asymmetric. They're kind of like L-shaped and like the top of the beak is flat and it's thinner than the bottom mandible. And Victor says this asymmetry is important. Because one of the mandibles keeps stationary and the other is moving. So that asymmetry is causing this directional flow. And that's something that flamingos do in comparison with other filter feeders like whales. Yeah, so flamingos are different filter feeders than whales. they're doing a lot more.

Got that. Okay. What other behaviors did they study? The second behavior that they looked at was the fact that flamingos stick their head, like, straight in and out of the water. It's like dipping. And because of the shape of the beak, this also creates vortexes. To study this part of eating, they trained these Chilean flamingos at the Nashville Zoo to feed in this aquarium tank. And they recorded these little water tornadoes, like with each dip of their beak.

And this helped the food. drift up into their beaks. That sounds delicious. Okay, so flamingos, quick summary, it's the chattering of the beaks in combination with the shape of the beak. Yeah, like, it's all of those things working together to, like, co-create these vortexes. What about the foot stomping? Yeah, so, like, Victor and his team studied that as well.

They created this, like, mechanical flamingo foot that was, like, flat when you stepped into the water. We know that flaming, when they are stomping, the foot to the sediments is opening. And then when it came up, it kind of retracted like an umbrella. And then when it's getting up, it's collapsing. What they are doing is producing a vortex. And that's how flamingo feet actually work in the wild. And in the lab, they saw that, yes, this motion also created vortexes.

They could stomp for food? Yep. while they are stumping frequently or marching like a dancing. On all of this, I can kind of see all these elements working together now that flamingos aren't just passive eaters. They are guiding this food into their mouth. Yeah. Remember we said they're predators, right? And that's the main idea Victor wanted to get across where, you know, they've combined all these different adaptations and behaviors into this like feasting dance.

Waterbenders among us. Right. I mean, even that skimming behavior I mentioned earlier, that movement helps create vortexes that bring particles of, like, food into their beaks that way, too. Is all of this, this dance unique to flamingos? Are there other birds combining multiple behaviors to create a whole symphony of vortexes? There is a kind of like sandpiper, like a small shorebird, and they do create vortexes. These birds are famous because they swim in circles. They are producing some vortices. They are lifting some of the particles, and they are feeding at the interface. But Victor says it isn't the same as flamingos.

But there is no other mechanism like flamingos because they are inside of the water. Well, let me ask you this, Gina, if flamingo feeding is so unique among birds, do scientists know anything about how flamingos evolve this way? Yeah, I mean, they know a little. They want to know more, definitely. and how they can find out more is by looking at babies. Baby flamingos. Yes, baby flamingos.

They do not have curved beaks. They have straight beaks. Yes. How do they eat? Well, the parents create this milk and they do feed them. But before the beaks start to curve, the juvenile flamingos do start to feed on their own. So, like, studying how flamingos feed when they transition from straight to curve beaks, could tell scientists a lot about, like, the ancestors of flamingos.

Also, Victor said that they. There's like a lot of filter feeder birds. And maybe scientists are missing something. Like maybe other birds right now are taking advantage of vortexes, but we just haven't looked at it enough. Right. Like maybe it's not unique among flamingos, but we'd have to do more research to find out.

Well, Gina, how could this work help people? Not to be all about us, but I am curious. I mean, I think it's a reasonable question, and that's one I asked Victor. And his answer was like really surprising. Because we know that flamingos. can extract particles the size of a cell. So we can think in that possibility

to make a bio-inspired engineering filter system based on flamingos that can extract effectively those microplastics. The filter system that flamigos use every day to eat could help humans develop filters that could clean our oceans. Oh. We can solve.

I mean, flamingos can solve and we can take advantage of that. A filter system that takes out microplastics inspired by flamingos, That's very cool. Yeah. Yeah. I mean, the flamingos, like, feed in these muddy waters.

Yeah. And it doesn't really clog their system. So this might be an ideal system to, like, really understand and mimic. So, yeah. So flamingos can help us make these, like, better, more active biofilters. The power of basic research or the power of flamingos, really. Yeah. Gina, thank you so much for bringing us this reporting on these birds and how they eat.

My pleasure. This episode was produced by Burley McCoy, edited by a showrunner Rebecca Ramirez and fact-checked by Tyler Jones. The audio engineers were Robert Rodriguez and Jimmy Keeley. Beth Donovan is our senior director and Colin Campbell is our senior vice president of podcasting strategy. I'm Emily Kwong and I'm Regina Barber. And thank you for listening to Shortwave from NPR.