16. Yawning May Have Other Evolutionary Qualities
Some scientists believe that yawning may have had a different evolutionary function. When you yawn, you usually open your mouth really wide. While you may not intentionally show everyone your teeth, if you make a considerable yawn, the people around you will probably see your pearly whites.
Some believe that yawning is an evolutionary behavior that allowed our ancestors to bare their teeth to animal predators or other people who may have posed a threat. This action is part of something called “comyawn” theory. It may have some validity, alongside other explanations for why we yawn.