It looked like the start of a really cute stretch—until the bunny opened his mouth as wide as could be to yawn. It was terrifying—but we couldn’t look away! This yawn video is one that bunny parents ...

A yawn is an involuntary reflex that involves opening the mouth wide and taking in a deep breath, followed by a slow exhale. Several theories exist about why we yawn, but researchers have not proven ...

Christine Calder 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 ...