Cats have whiskers for the same reason dogs do – to help sense -- and often rely on them more than dogs, as cats are more likely to put themselves is precarious positions.
Whiskers are tactile hairs found in mammalian skin -- usually the muzzle, lip, eyelids, face, and throat. They are also known as sinus hairs (or vibrissae). The base of the hair is embedded into a sinus that contains many nerve fibers. These special hairs detect pressure and can aid in movement by enhancing the animal's ability to sense its surroundings.