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 ...

That slightly open mouth while concentrating. The subtle parting of lips during sleep. The tendency to breathe through your mouth instead of your nose during exercise. These seemingly innocent habits ...

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 ...

Dear Eric: I play cards weekly with a group. One of the women sometimes chews gum during our games, noisily and with her mouth open. This is worse than fingernails on a chalkboard to me. Why do ...

I just turned 63 – that I have more episodes of dry mouth. I’m told this isn’t unusual for older people. Why would that be?

Dolphins living in captivity often make an open-mouth facial expression while playing with each other. Zoomarine, Italy Bottlenose dolphins “smile” at each other while playing, making open-mouth ...

Everybody is used to cats purring. Sometimes they do other things while purring, like "making biscuits" (kneading with their paws) or rubbing their head against whatever is closest to them. When cats ...