Flamingos use different techniques to create water tornadoes to trap their prey. Take a look in the video above or watch on YouTube. Image via Víctor Ortega Jiménez. Used with permission.
A flamingo's long legs, webbed feet, S-shaped neck and angled but flattened beak may make it look gangly, but a team of scientists has found these characteristics all serve a purpose. The team studied a group of Chilean flamingos at the Nashville Zoo and then created artificial copies of the flamingos' beaks and legs to observe in the laboratory. The researchers said on May 12, 2025, that flamingos' unique body parts, combined with specialized movements, create water vortices to trap their prey.
Lead author Víctor Ortega Jiménez, an assistant professor of integrative biology at the University of California, Berkeley, collaborated with researchers at the Georgia Institute of Technology in Atlanta; Kennesaw State University in Marietta, Georgia (KSU-Marietta); and the Nashville Zoo. They published their study on May 12, 2025, in the peer-reviewed journal Proceedings of the National Academy of Sciences.
Although from a distance it may seem like flamingos barely move while feeding, when viewed up close, one realizes that a lot is going on under the surface. Flamingos combine the movements of their legs, head and beak to create eddies in the water.
The food they feed on - such as brine shrimp and other small animals - gets caught in these little eddies. This is when the flamingos suck in their prey.
To clearly study these animals' movements, scientists taught a group of Chilean flamingos at the Nashville Zoo to feed from a transparent aquarium. The research team filmed the flamingos while they fed.
They also used a laser to illuminate what was happening around the flamingos' L-shaped beaks and heads. They were able to see the bubbles and vortices the flamingos produced.
Once they had observed the animal's movements, the scientists created an artificial model of both the beak and the legs. This 3D model mimicked the exact movements these animals produce. This artificial version allowed the scientist to conduct a more detailed analysis in the laboratory.
Anyone who sees a flamingo eating might wonder why they have such a funny dancing step with their heads underwater. This is also what lead author Víctor Ortega Jiménez wondered when he took a trip to the Atlanta Zoo with his family.
Ortega Jiménez, who specializes in biomechanics, was impressed by these strange postures. He observed their splashing, the shape of their beaks and the ripples that formed around them. Ortega Jiménez concluded it was no coincidence flamingos move this way. He found that flamingos are not passive feeders, but rather they are hunters:
Flamingos are actually predators. They are actively looking for animals that are moving in the water. And the problem they face is how to concentrate these animals, to pull them together and feed. Think of spiders, which produce webs to trap insects. Flamingos are using vortices to trap animals, like brine shrimp.
He added:
It seems like they are filtering just passive particles, but no, these animals are actually taking animals that are moving.
It all starts with the feet. Flamingos have webbed feet that are flexible. When they are about to eat, they create vortices by stomping in the water with their webs open. The open webbing is much more effective at pushing vortices from the ground. This is different than when they are simply walking with a collapsed webbing, which makes the birds more agile.
By the way, because flamingos stir up both sediment and food, they have filters in their beaks so they don't swallow anything that isn't food.
In addition to using their flexible, webbed feet to stir up sediment and food from the bottom and propel it upward in spirals, flamingos also propel their heads upward in the water to create a vortex that spins around a vertical axis. This concentrates food particles. These tornadoes are strong enough to trap even agile invertebrates, such as brine shrimp and microscopic crustaceans called copepods.
Additionally, flamingos employ another strategy known as chattering. Their heads remain upside down within the aquatic vortex, while their angular beaks rapidly open and close. This creates smaller vortices that direct sediment and food toward their beaks. In this case, the flamingos keep their upper beaks stationary (although they are capable of independent movement) and move only their lower beaks about 12 times per second during chattering, as Ortega Jiménez discovered.
Scientists verified in the laboratory how vital this strategy is to flamingos' feeding. To do so, they used a 3D model of a flamingo's beak, which simulated chattering. They also added a small pump to the mouth to simulate how food trapped in the beak is sucked in. Ortega Jiménez said:
The chattering is actually increasing the number of brine shrimp passing through the tube sevenfold. So it's clear that the chattering is enhancing the number of individuals captured by the beak.
The flamingo's beak is unique. It is flattened at its angled front end, so that when the bird's head is upside down in the water, the flat part is parallel to the bottom. This allows flamingos to use another technique called skimming. Skimming involves using its long, S-shaped neck to propel its head forward while rapidly moving its beak, creating sheet-like vortices (von Kármán vortices) that trap its prey. Ortega Jiménez said of this impressive trick:
We observed when we put a 3D printed model in a flume to mimic what we call skimming, they are producing symmetrical vortices on the sides of the beak that recirculate the particles in the water so they actually get into the beak. It's this trick of fluid dynamics.
The principles the researchers discovered could be used to design more effective systems for concentrating and suctioning tiny particles, such as microplastics present in water, and also to create more advanced self-cleaning filters.
Furthermore, engineers could design robots that, like flamingos, can navigate efficiently in mud. When walking or running, flamingos appear to slide their feet in the water rather than stomping, a technique that could help robots navigate in water or mud without sinking or getting stuck. According to Ortega Jiménez:
Flamingos are super-specialized animals for filter feeding. It's not just their head, but their neck, their legs, their feet, and all the behaviors they use to effectively capture these tiny and agile organisms.
Bottom line: According to a new study, flamingos are active hunters! With their unique body parts and movements, they create water vortices to capture their prey.
Source: Flamingos use their L-shaped beak and morphing feet to induce vortical traps for prey capture
Via UC Berkely