The flamingos do not filter only: beat beak and feet to create vortices that concentrate crustaceans and larvae, transforming the water into a trap.
For us humans, a pink and curious appearance creature can be the model for a beach inflatable, but not a credible predator … instead no: the flamingos are efficient hunters, able to generate vortices underwater that trap the prey they feed on.
Predators. This was discovered Victor Ortega Jiménez, of the University of California, Berkeley, who decided to observe what exactly the flamingos do when they are with the head immersed in the low brackish waters in which they live.
It was thought that they limited themselves to filtering the water, with their beak specialized in retaining algae, larvae, small crustaceans (the algae and crustaceans that eat them provide flamingos with carotenoids that make their plumage pink).
The study. “Instead they use the movements of the head, the long neck and the palmate feet to create” fluid traps “that help them capture the prey,” says Victor Ortega Jiménez.
The researcher studied the flesyphics of Chile, widespread in South America, close relatives of the flamingos we see in Europe. «We observed them in a transparent tank, making fluid dynamics measurements. Then we reconstructed their l and the legs in 3D in 3D, to reproduce two movements: the rapid beating of the beak and the trampling with the feet ».
Vortici. Thus Ortega Jiménez saw how the flamingos exploit physics: “the” dance “in which they beat their feet produces a horizontal vortex that raises prey and food particles. They position the head in front of the feet and rapidly lift it vertically: so they create a suction effect, forming other vortices similar to small tornadoes, which concentrate and trap the prey ».
The vortices proved to be strong enough to capture tiny crustaceans, such as those of the genus Artemia. Finally, concludes the researcher, “opening and closing the jaws produce a flowing flow towards the beak that facilitates capture”.
