Why do cats have whiskers?

A cat’s whiskers are no fashion statement, but purely functional. To the feline owner, whiskers serve three purposes: navigation, mood indication and measuring an opening. Whiskers help the cat feel its way around. At night, this helps a cat slink its way through a room and not bump into anything. Whiskers are also a good indicator of mood. Pulled back, they express anger. But the whisker’s primary use is to help a cat judge whether or not he’ll fit through an opening.