Why Do Flamingos Stand on One Leg?

Two pink flamingos in flight Adult and sub-adult greater flamingo in flight in Walvis Bay

The Greater Flamingo (Phoenicopterus roseus) is one of the most unique migratory birds. It’s large, with a wingspan that can reach up to 1.8 meters, and the pink of its feathers is a rare color in the animal world. It gathers in colonies of thousands of individuals, creating a dazzling spectacle in saline waters.

But even more surprisingly, when it sleeps, the greater flamingo adopts a very particular position: it stands on one leg only and tucks its head under its wing. For humans, it’s obviously astounding, as it seems quite challenging to fall asleep on one leg. However, the flamingo has no balance issues; it remains stable on a single webbed foot.

Does the Flamingo Keep Warm by Sleeping?

The animal’s body is covered in feathers, while its lengthy legs remain exposed and extremely susceptible to the cold, a weather circumstance that affects it significantly. Some bird species descend to the ground and land on their legs to endure drops in temperature. Yet, for the pink flamingo, it finds it simpler to encase one leg within its feathers. Scientists have previously believed that the flamingo assumes this stance to minimize heat loss, particularly because the bird frequently sleeps while balancing on one leg in the water.

An alternate theory suggests that the flamingo uses single-leg sleep as a way to give rest to the other leg. According to a study by scientists from the Georgia Institute of Technology (USA), the bird needs to exert hardly any muscular effort to hold itself in this surprising position. This might explain why the flamingo chooses to slumber on just one leg.

When the pink flamingo lifts one leg, its body relaxes and tilts slightly forward due to gravity. It then locks into a highly stable position, the one we recognize in a sleeping flamingo. By observing this phenomenon on a flamingo cadaver, American researchers have uncovered this mechanism. The explanation is consistent with the idea of heat conservation, since in this particular position, the bird expends virtually no energy.