Why do cats' whiskers break off?

Cat's whiskers occasionally fall out just as regular hairs shed, but replacement whiskers will grow back in their place, according to About.com. Cat whiskers are twice as thick as a cat's ordinary hair, and the roots go up to three times deeper than normal cat hairs.

Cat whiskers are extremely sensitive and are able to feel even the slightest whisper of a breeze. They also have other useful functions. For example, they are about as wide as the cat's body, so they act as a useful measuring tool. Furthermore, they are used to keep track of prey, such as a mouse that the cat has just caught.