Animals and Insects

Scientists Tackle The Big Question: How Flamingos Sleep On One Leg

Researchers discovered when flamingos stand on one leg they use no muscular effort to do so. This is due to their unique skeletal system and gravity.

Scientists Tackle The Big Question: How Flamingos Sleep On One Leg
Getty Images / Blazquez Dominguez

Flamingos are so good at standing on one leg, they do it in their sleep. But why? 

Researchers think they do it to conserve body heat and fight muscle fatigue. A new study backs up one of those theories.

Scientists arranged flamingo cadavers in a one-legged stance. They found that flamingos support their weight on one leg without using muscle activity — and yes, it even works when they're dead.

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The birds — the live ones — also sway significantly less on one leg while they're sleeping than they do when they're awake.

The secret to flamingos' balance is their unique skeletal system. When dozing off, they pick one leg up and move the other directly underneath their body. Their leg will lock in place, and with the help of gravity, it keeps them balanced.

And they're not the only birds that sleep on one leg. Cardinals and finches use a tendon in their heel to tighten their grip on branches while their body weight keeps them upright all night.