For years, researchers thought a yawn was just a deep breath that took in a rush of oxygen and flushed out carbon dioxide. They dropped that idea after some experiments showed that breathing extra oxygen didn’t reduce yawning, and having extra carbon dioxide didn’t increase it.
Now researchers have an idea that because yawning is “contagious” (seeing someone yawn can make you yawn, too), it may help a group of people or animals go to sleep or wake up at the same time. Yawning might help wolf pups settle down to rest together or help human families wake up to start the day.
There is more to learn about yawning. For example, do researchers feel sleepy while they’re studying it? ZZzzzzzz.
Art by: Cedric Hohnstadt