Lockjaw (trismus) is a painful condition that limits your ability to open your mouth all the way. It occurs when the muscles you use to chew spasm, meaning they can’t relax completely. The term ...

Dolphins are known for what appear to be big, contagious smiles. But do they actually, well, smile? The answer, according to a new study of dolphin play, is a resounding “maybe.” Dolphins use their ...