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.