Flamingo Knees

A flock of flamingos can resemble a water ballet troupe. They preen their feathers, swim together and stand on one leg for hours at a time—they even sleep that way! Scientists are still trying to figure out why and how flamingos do it, but they have discovered some important clues.

It takes a lot more effort to stand on one foot than it does to balance on two, so scientists have wondered if the reason that flamingos can do it so easily is that they don’t have to use their muscles as much. The answer may have something to do with the way flamingos’ legs are structured. The upper and lower bones of a flamingo’s leg are almost exactly the same length. This is similar to the way human legs are structured, and it means that the flamingos’ legs don’t have to support as much weight as ours do.

Flamingos also have other structural advantages that allow them to keep their balance without putting too much strain on their muscles. For example, their feet have scaled parts and their ankles have a joint that snaps shut to lock the foot-to-leg junction in place. In fact, this ankle has a special mechanism that is the key to flamingos’ amazing balance.

Another important factor is that flamingos’ feathers are specially adapted for swimming. They have a small, delicate accessory feather that arises from the end of the main feather at the point where it merges into the shaft. The wing feathers also have an aftershaft that extends from the base of the shaft, forming a small triangle in front of the wing. This helps to focus the flamingo’s flight energy in the center of its body, making it more stable in the air.

Finally, flamingos’ bills are uniquely adapted for filter feeding. The top and bottom of their beaks have bristled, comb-like structures called lamellae that intertwine when they meet to form a filtering mechanism. This allows the birds to scoop up the tiny crustaceans, mollusks and algae they feed on.

Many scientists have suggested that flamingos stand on one leg in order to save body heat in cold weather, or that it might help them camouflage themselves in a lagoon by mimicking reeds or trees. A recent study, however, ruled out both of these explanations as the reason for flamingos’ odd behavior. The researchers found that flamingos conserved no more body heat by standing on one leg than they would if they stood on two legs, and their habit of doing so didn’t help them balance in windy conditions.

One popular theory is that flamingos stand on one foot to avoid predators. This is less plausible than the camouflage theory, because the flamingos’ natural habitat—a shallow lake or lagoon—is full of long, thin objects like reeds and trees. Also, flamingos are just as likely to stand on one leg in hot weather as in cool weather.