Cats have whiskers to help them gather information about the natural world around them. The extremely sensitive tactile hairs are able to detect subtle vibrations and wind currents, and can also be used as a measuring tool to determine whether or not a cat will fit into an opening. Studies have suggested that whiskers are crucial to a cat's sense of balance and spatial relationships. Whiskers are known by the Latin name of vibrissae, which is a generic name for any sort of stiff, large, extra sensitive hair used as a sensory tool by animals. Mammals of all sizes from mice to horses have vibrissae, and are highly attuned to small changes in their environment as a result.

The whiskers of a cat are much thicker than conventional hairs, and the hairs are also more deeply rooted so that they cannot be dislodged as easily. Pet owners may have noticed that cats have whiskers on the whisker pad around their noses, above their eyes, and behind their front legs. Cats have whiskers in multiple locations to collect different types of information which contribute to an overall big picture of a scene.

On the face, cats have whiskers so that they can feel out obstacles. If a cat is trying to slip into or under something, he or she will test it out with whiskers first. The whiskers around the nose and eyes are a little bit longer than the width of the cat's body, so if the whiskers are heavily compressed, the cat knows that the hole is too small. Facial whiskers are also used to feel for slight breezes and changes in temperature. Wind currents can indicate the location of furniture, open doors, and other matters of interest to a feline, just as temperature changes can.

Cats have whiskers on their legs to help them keep track of prey animals. Leg whiskers help cats to figure out how large a prey animal is and where exactly it is located, useful for a shortsighted animal like a cat. Some animal behaviorists suspect that cats have limited close up vision, and that cats have whiskers and an acute sense of small to assist with handling prey in close quarters.

Whiskers can also be used to judge mood. A curious cat often thrusts the whiskers forward to explore. Relaxed, confident cats have whiskers with a forward tilt as well, indicating that the animal feels secure and interested in his or her surroundings. When a cat is tense or unhappy, the whiskers are pulled back against the face.

Because cats have whiskers to help them navigate, damage to their whiskers can be debilitating. Whiskers should never be cut or trimmed, and excessive handling of whiskers should be avoided, as manipulation of the whiskers can be painful. Whiskers do periodically fall out and grow back, which is normal, but if a cat loses a large number of whiskers, it may be a sign of fighting or health problems.