Cats are the most carnivorous of all the carnivores. This means that they feed almost entirely on other animals with backbones. All cats are hunters and their good eyesight plays an important part in this: in good light they see about as wall as humans do, but in poor light their vision is six times sharper. Hearing and smell is less well developed than in the dog family. There are seven species of big cat and 28 species of small cat. Cheetahs, Jaguars, Leopards and Pumas are the major types of wild cats in the world.