Cats can regrow hair after cutting or grooming, but it takes from 3 to 4 months for regrowth to occur. In long-haired cats, it can take even more time.
The purpose of cat hair is to protect the cat from harm from insects, enhance the cat's sense of touch and regulate the cat's body temperature. Cats have four different types of hair, including the long coarse hairs that insulate the body. Cats also has thin awn hairs that are located within the coat that protect and insulate their bodies. Secondary hairs are the hairs found on the cat's undercoat, which are the thinnest hairs and serve the purpose of controlling the cat's temperature. Finally, the cat's whiskers are the long hairs that protrude from the cat's face and are connected to nerve cells.
Cats are very good about grooming themselves and do so many times each day. Cats use their tongues to groom their bodies, and cats' tongues are especially rough for this purpose. The roughness of the tongue allows cats to remove dead skin and lose hair.
Cats with darker coats have naturally glossy sheen. Healthy cat hair is unbroken and glossy. Brushing a cat's hair regularly can help the coat stay healthy and beautiful.