If you have a big brain, you can credit yawning for promoting brain growth and activity, researchers have found. And if you have a small brain, you can blame the fact that you don’t yawn long enough. By “you,” psychologist Andrew Gallup of the State University of New York at Oneonta and his colleagues mean “your species.”
In the paper in Biology Letters, they report that the average duration of yawns in 109 individuals from 19 species—from humans, African elephants, and walruses to mice, and rabbits, and capuchin monkeys—predicts a species’ brain weight and its number of cortical neurons. Not only that, the act of opening our jaws and sucking in air seems to have physiological benefits. FULL STORY
