Animal Mysteries: Why Do Flamingoes Stand on One Leg?

Flamingos have to be one of the most well-balanced creatures in the animal kingdom -- literally. The charming birds are often seen sleeping serenely perched on just one leg with no trouble at all. Any person who has tried a tree pose in yoga knows how difficult it is to balance on a single leg. So how do flamingos manage it effortlessly?

According to a report from Washington Post, a pair of biologists from Atlanta set out to solve this intriguing mystery.

There were already a couple of theories floating around. Some have suggested that the practice is to conserve body heat that flamingos lose while wading in cold water. Others believe it's to reduce muscle fatigue and rest one leg while the other supports the body.

To find some answers, Young-Hui Chang of Georgia Tech and Lena Ting of Emory University went to Zoo Atlanta armed with a fancy 3-D bathroom scale that measures the force that a foot exerts in all directions, according to a report from The Atlantic. One flamingo fell asleep on this force-plate and the scientists noticed that the animal became even more stable as it lost consciousness with less swaying and a center of gravity that shifted by millimeters.

Zoo employees all said that they couldn't remember one occasion of a flamingo ever falling down.

Chang and Ting visited Birmingham Zoo to examine two recently euthanized flamingos, which the researchers then defrosted and dissected. When Chang picked up one by the shin, the leg locked into place, completely rigid and stable. Apparently, these amazing creatures can keep their balance even when dead.

When humans try to stand on one leg, they have to constantly activate their musles in order to make tiny adjustments to the unnatural position. On the other hand, the flamingo's body weight shifts, automatically stabilizing the joints of their standing leg and they are able to stand without any muscular activity.

Specifically, the foot shifts from under the hip to under the center of the body. The flamingo's center of mass also moves in front of its knee, which is tucked unseen under all the feathers, and the body weight pulls the hip and knee forward. Both changes to the flamingo's posture help keep the joints locked in place.

Interestingly enough, this natural mechanic is only activated on one leg, so it's actually more stable in its position than on two legs.

The study was published in Biology Letters.