Whiskers

Whiskers are specialized hairs found on the faces of mammals such as cats, mice, and similar. They are notably different from standard hair (fur) in that they serve as a sensory mechanism--the animal is sensitive to objects touching its whiskers (via touch sensations on its face, as (like normal hair) whiskers are nonliving material have no nerves in themselves), and uses this to help navigate in conditions where other senses are unusable or to supplement these senses. The length of a creature's whiskers often corresponds to the width of the creatures head or body, to help in determining whether or not the creature can, for example, fit through a small opening.