A tooth (plural teeth) is a small, calcified, whitish structure found in the jaws of many vertebrates and used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are covered by gums. Teeth are not made of bone, but rather of multiple tissues of varying density and hardness. The general structure of teeth is similar across the vertebrates, although there is considerable variation in their form and position.