Brain scientist Andrew Gallup is fascinated with the yawns of people and animals. Why? It turns out that this behavior can tell us something about brain size and complexity.
Gallup did a study with his students at SUNY Polytechnic Institute in Albany, New York. They timed 205 yawns across 24 different species of mammals. The group compared these yawn times with brain measurements from each species in the study. They compared mammals of all sizes—from African elephants to mice.
The group found that the larger and more complex a mammal’s brain, the longer the animal yawns. Humans have the longest yawns—averaging about 6.5 seconds. Mice have the shortest, yawning for slightly less than 1 second.