No one knows for sure why we yawn, but there are several theories.
Most say it is because our bodies run low on oxygen when we’re tired and not breathing energetically.
We involuntarily open up and suck some air in to catch up.
Some believe it’s also a way the body cools itself when it’s getting too warm.
People yawn when they are sleepy, and they yawn when it is warm and they are contented.
Oftentimes when one person yawns, more people will follow suit, as if it is contagious.
In fact, some of you may be yawning right now just from reading about yawns, thanks to the power of suggestion.