Yawning is contagious and can be very embarrassing. But apart from unpleasant experiences, why we yawn?
Yawning is a reflex present not only in humans, but in animals. It’s universal. All animals yawn: mice, kittens, dogs, monkeys. Therefore, its function should be universal too.
A proposal is that yawning increases the blood flow through the brain and cools it down.
Recently, it was found that small-brained animals, like mice, have shorter yawns, about 1.5 seconds. And larger-brained, like humans or elephants, 6 seconds. That means that larger-brained animals like us need longer yawns to increase the blood flow through our larger brains and cool it down.
So, although the jury is still out, next time you need to cool down, try a slow and long yawn! Everybody will understand. Don’t you think?