Why do we yawn? Yawning is a universal gesture. Everyone yawns, from babies still in their mother's womb to the elderly.

How come yawns are so contagious? asks Danielle Sinacori, a student from Wantagh. Monkey see, monkey do? Just watch as someone's head tilts back, mouth drops open, eyes squint, and forehead furrows.

That strange urge to yawn when someone else does is called 'contagious yawning', and it's one of those human quirks we still ...

Sign up for CNN’s Sleep, But Better newsletter series. Our seven-part guide has helpful hints to achieve better sleep. Find yourself yawning a lot? Do you need that ...

Johanna Simkin does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond ...