Although snakes are cold-blooded and depend on the environment to regulate their body temperature, they are found on every continent save Antarctica. There are over 3,000 species of snake.
Most snakes lay eggs. The only snake known to build a nest for its eggs is the king cobra. Other species, such as garter snakes, give birth to live young. This is because they live in places where it is too cold to lay eggs, so the young develop inside the mother's body.
Snakes only eat meat, though some species eat eggs. These snakes break the swallowed egg with hard protrusions in their spines and then digest the contents. Other snakes chase down prey and swallow it whole. Venomous snakes use venom to immobilize their prey, while snakes such as pythons squeeze their prey to death. Because snakes can unhinge their jaws, they can swallow prey much larger than their own heads. A snake's slow metabolism means it does not have to eat as often as a warm-blooded creature.
Snakes do not have eyelids or ears. This is how they are differentiated from legless lizards such as the glass lizard. However, snakes perceive vibrations in the ground and smell the air with forked tongues.