Whiskers give cats important sensory information and also have a role in communication between cats.
They are far more important to a cat than a dog’s whiskers are to a dog, and they should never be trimmed, as they tell a cat whether it can squeeze through a narrow passage, for example.
Technically called vibrissae, whiskers or tactile hairs are clustered in three major groups on the sides of the cheeks, above the eyes, and farther back on the cheeks. There are also a few on the chin and shorter ones on the back of the front legs.
Stiffer and at least twice as thick as ordinary hairs, vibrissae have roots that go three times as deep in the skin and are surrounded by nerves and blood vessels. The slightest motion of a hair, even from a breath of air, triggers a sensation.
Vibrissae are helpful to a cat maneuvering in dark areas, especially when hunting, and when a cat has prey in its cupped paws, ready to move it toward the mouth, the hairs give signals of the next meal’s exact position.
As for communication between cats, whiskers pushed forward may indicate friendliness or inquisitiveness, but when they are pulled back flat against the cheeks, they can signal either aggressive or defensive hostility.
In either case, be sure to spray your pant legs and carpet, not the cat.