The rough surface of a cat's tongue serves several purposes, including grooming, hunting and eating. The small barbs face backward on a cat's tongue and are called "filiform papillae." The papillae are filled with keratin, a fibrous protein found in skin and nails.
The backward barbs on the tongue help the cat to remove extra fur and dirt from his coat. When a cat hunts, the tongue's rough surface secures his prey and scrapes flesh from the prey's bones. Mushroom-shaped papillae on the tip, sides and back of the tongue contain a few taste buds, although the temperature, smell and texture of food is more likely to entice a cat to eat than the taste.