Snakes are famous for their long, limbless bodies that slither from place to place. Their anatomy is quite interesting, and we will learn about it in this lesson. There are over 3000 species of snakes, and they are in the vertebrate class reptilia in the animal kingdom. Within this class are other reptiles, and snakes are most closely related to lizards. They are in the same order, which is called squamata. Believe it or not, snakes are not the only legless reptile species. There are actually legless lizards that may look similar, but only snakes share all the characteristics that make them a unique group.