Crocodililans are able to close off the ear canals and throat with valves. These adaptations come in handy for attacking prey underwater. The group scientifically known as Squamata contains more than 6,000 species of snakes, lizards, and amphispaenids or worm lizards. There are about 2,700 different types of snakes in the world. Snakes do not have legs, eyelids or ears.
Some snakes kill their prey by constricting, others with venom.
But the majority will bite and hold on to their victim. All snakes swallow their prey whole. The largest sub-group of reptiles are the lizards, with over 3,000 species. All lizards have external ear openings and movable eyelids. Some lizards are legless.