Flamingos: The Water-Bending Physics Masters

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 [email protected] mailto:[email protected] 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 http://plus.npr.org/shortwave. 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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• 0:00Speaker 00

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• 0:18Emily Kwong?

  You're listening to Short Wave from NPR. Hey, Short Wavers. Emily Kwong here with my co-host and our resident physicist, Regina Barber. Hey, Gina.

• 0:29Regina Barber?

  Hey, Em. I have a really important physics question for you.

• 0:33Emily Kwong?

  OK, what?

• 0:34Regina Barber?

  OK. Do you like flamingos?

• 0:36Emily Kwong?

  I love all birds, but flamingos are among the weirdest and the coolest.

• 0:40Regina Barber?

  I think so.

• 0:41Emily Kwong?

  What does that have to do with physics?

• 0:43Regina Barber?

  I'm going to show you a video of one feeding now.

• 0:45Emily Kwong?

  OK.

• 0:45Regina Barber?

  Go ahead and pull it up.

• 0:47Emily Kwong?

  Oh, this is cute. OK, so yes, we have this, the classic pink, leggy flamingo.

• 0:52Regina Barber?

  Yeah.

• 0:52Emily Kwong?

  But he's eating by dipping his head in the water.

• 0:55Regina Barber?

  Yeah, he's got this curved beak at the end of his long neck and this large tongue.

• 0:59Emily Kwong?

  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.

• 1:04Regina Barber?

  Yeah, yeah. And you'll notice his head is like upside down, like his eyes are going in first into the water.

• 1:08Emily Kwong?

  Yeah.

• 1:09Regina Barber?

  And this pretty unusual feeding behavior like caught the eye of Victor Ortega Jimenez, and he studies biomechanics.

• 1:15Emily Kwong?

  Oh, so he studies how living things move?

• 1:17Regina Barber?

  Yes, correct. So back in 2019, during a trip to the Atlanta Zoo, Victor saw the flamingos feeding, like opening and closing their beaks 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?

• 1:37Speaker 03

  The mystery of these magnificent birds, what are they doing inside of the fluid? No? 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.

• 1:54Emily Kwong?

  OK, this is a fluid dynamics story, isn't it?

• 1:57Regina Barber?

  Yes.

• 1:58Emily Kwong?

  That's the physics part.

• 1:58Regina Barber?

  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.

• 2:10Emily Kwong?

  Nice.

• 2:11Regina Barber?

  And, Em, 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.

• 2:22Regina Barber?

  So much of the 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.

• 2:50Speaker 03

  We observed that they were producing some tornado-like vortices. And we know tornadoes can be destructive, but they are very effective to leave particles from the ground or from the bottom, in this case of sediments.

• 3:03Regina Barber?

  Today 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 Short Wave, the science podcast from NPR.

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• 4:48Emily Kwong?

  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?

• 5:04Regina Barber?

  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.

• 5:18Emily Kwong?

  Oh, so they're like whales?

• 5:19Regina Barber?

  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.

• 5:38Emily Kwong?

  Oh, so that's why they flock to these harsher waters?

• 5:41Regina Barber?

  Yeah, and be that salty, muddy waters, or really, really hot waters. Here's Victor Ortega Jimenez again.

• 5:48Speaker 03

  And actually, some of the flamingos also can live in springs. The temperatures are at the point of boiling water.

• 5:56Emily Kwong?

  What?

• 5:57Speaker 03

  So, and yeah, so flamingos are just these extreme animals that lives in these environments.

• 6:04Emily Kwong?

  Flamingos are eating out of the hot tub.

• 6:06Regina Barber?

  Yeah. Like, this whole story, like, I was getting so much new information. But let's go back.

• 6:14Emily Kwong?

  Okay.

• 6:15Regina Barber?

  Let's go back to that day at the Atlanta Zoo where 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 flamingos' 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 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?

• 6:56Emily Kwong?

  Yeah, and like, why are they stomping their feet?

• 6:58Regina Barber?

  Right, right. Why do they march? And like, why do they chatter their beaks and like opening and closing it 12 times a second?

• 7:06Emily Kwong?

  Wow, that's a lot.

• 7:07Regina Barber?

  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 behaviors individually.

• 7:17Emily Kwong?

  All right, walk us through, which behaviors did he focus on?

• 7:20Regina Barber?

  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.

• 7:32Emily Kwong?

  Okay.

• 7:32Regina Barber?

  So that they could bring that footage back to their lab 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.

• 7:47Emily Kwong?

  What were they trying to figure out?

• 7:48Regina Barber?

  They were trying to figure out like, what is this chattering doing?

• 7:51Speaker 03

  Our question was, what is producing that directional flow? Is the tongue, or is just the chattering? And what the surprise is that we observe that directional flow without the tongue.

• 8:02Regina Barber?

  So it's not making the water spin? No, it's, 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.

• 8:12Emily Kwong?

  Oh yeah, because I guess flamingo beaks are curved, right?

• 8:15Regina Barber?

  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.

• 8:28Speaker 03

  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.

• 8:42Regina Barber?

  Yeah, so flamingos are different filter feeders than whales. They're doing a lot more.

• 8:47Emily Kwong?

  Got that, okay. What other behaviors did they study?

• 8:50Regina Barber?

  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.

• 9:17Emily Kwong?

  That sounds delicious.

• 9:18Regina Barber?

  Okay, so flamingos, quick summary, it's the chattering of the beaks in combination with the shape of the beak.

• 9:27Emily Kwong?

  Yeah.

• 9:27Regina Barber?

  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.

• 9:43Speaker 03

  We know that flamingos, when they are stomping, the foot to the sediments is opening.

• 9:49Regina Barber?

  And then when it came up, it kind of retracted like an umbrella.

• 9:52Speaker 03

  And then when it's getting up, it's collapsing. What they are doing is producing a vortex.

• 9:58Regina Barber?

  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.

• 10:09Speaker 03

  Well, they are stomping frequently or marching like a dancing.

• 10:15Regina Barber?

  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 that 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. 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?

• 10:59Regina Barber?

  There is a kind of like sandpiper, like a small shorebird, and they do create vortexes.

• 11:04Speaker 03

  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.

• 11:14Regina Barber?

  But Victor says it isn't the same as flamingos.

• 11:16Speaker 03

  But there is no other mechanism like flamingos because they are inside of the water.

• 11:20Regina Barber?

  Well, let me ask you this, Gina. If flamingo feeding is so unique among birds, do scientists know anything about how flamingos evolved 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.

• 11:36Emily Kwong?

  Baby flamingos.

• 11:37Regina Barber?

  Yes, baby flamingos. They do not have curved beaks.

• 11:41Emily Kwong?

  They have straight beaks.

• 11:42Regina Barber?

  Yes.

• 11:42Emily Kwong?

  How do they eat?

• 11:43Regina Barber?

  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 curved beaks.

• 11:56Emily Kwong?

  Yeah.

• 11:56Regina Barber?

  Um, could tell scientists a lot about like the ancestors of flamingos. Also, Victor said that 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.

• 12:12Emily Kwong?

  Right. Like maybe it's not unique among flamingos, but we'd have to do more research to um, to find out. Well, Gina, how could this work help people? Not to be all about us, but I am curious.

• 12:23Regina Barber?

  I mean, I, I think it's a reasonable question and that's one I asked Victor. And um, his answer was like really surprising.

• 12:30Speaker 03

  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.

• 12:44Regina Barber?

  The filter system that like flamingos use every day to like eat could help humans develop filters that like could clean our oceans.

• 12:51Emily Kwong?

  Oh.

• 12:52Speaker 03

  We can solve, I mean flamingos can solve and we can take advantage of that.

• 12:57Emily Kwong?

  A filter system that takes out microplastics inspired by flamingos, that's very cool.

• 13:02Regina Barber?

  Yeah, yeah. I mean, the flamingos like feed in these muddy waters.

• 13:07Emily Kwong?

  Yeah.

• 13:07Regina Barber?

  And they, it doesn't really clog their systems. 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.

• 13:22Emily Kwong?

  The power of basic research or the power of flamingos, really.

• 13:26Regina Barber?

  Yeah.

• 13:26Emily Kwong?

  Gina, thank you so much for bringing us this reporting on these birds and how they eat.

• 13:31Regina Barber?

  My pleasure, Em.

• 13:35Regina Barber?

  This episode was produced by Burleigh McCoy, edited by our showrunner, Rebecca Ramirez, and fact-checked by Tyler Jones. The audio engineers were Robert Rodriguez and Jimmy Keely.

• 13:44Emily Kwong?

  Beth Donovan is our senior director, and Colin Campbell is our senior vice president of podcasting strategy. I'm Emily Kwong.

• 13:50Regina Barber?

  And I'm Regina Barber.

• 13:51Emily Kwong?

  And thank you for listening to Short Wave from NPR.

• 14:04Emily Kwong?

  Stay tuned for the following announcements and messages from our sponsors.