Everybody yawns

Scientists studying this reflex have proposed several reasons for the phenomenon. A yawn is a reflex that may be triggered by sleepiness, stress, boredom, or seeing another person yawn.

There are several reasons for yawning. snakes yawn to realign their jaws after eating and to aid respiration. Fish yawn when their water lacks sufficient oxygen. However, it is more difficult to pinpoint why humans yawn.