Humans aren’t the only animals that yawn. Many animals, from parakeets to elephants, exhibit this behavior. But why do they do it? One hypothesis is that yawning may cool off the brain. New findings from scientists at the State University of New York at Oneonta support this idea.  

Psychologist Andrew Gallup and colleagues watched YouTube videos of 29 mammals—including mice, cats, walruses, and elephants—yawning. They found that animals with larger brains tend to have longer yawns. 

Yawning can cool the brain in a few ways: It increases blood flow, bringing cooler blood up from the heart. And it allows the body to release heat to the outside world through the mouth and airways.