 Cats are known for spending considerable amounts of time licking their coat to keep it clean . The cat 's tongue has backwards @-@ facing spines about 500 μm long , which are called papillae . These contain keratin which makes them rigid so the papillae act like a hairbrush . Some cats , particularly longhaired cats , occasionally regurgitate hairballs of fur that have collected in their stomachs from grooming . These clumps of fur are usually sausage @-@ shaped and about 2 – 3 cm ( 0 @.@ 8 – 1 @.@ 2 in ) long . <unk> can be prevented with remedies that ease elimination of the hair through the gut , as well as regular grooming of the coat with a comb or stiff brush . Some cats can develop a compulsive behavior known as psychogenic alopecia , or excessive grooming . 
