All snakes eat meat and are highly specialized for acquiring their food. Because they have no limbs and no way to manipulate food, snakes must swallow their prey whole. Snakes can unhinge their jaws, allowing them to swallow prey about twice the size of their heads. Prey animals vary according to the size and species of snake but include insects, worms, fish, amphibians, lizards, birds, eggs, other snakes, and small mammals.
All snakes have teeth, but only venomous snakes have fangs.
Venom is actually a combination of enzymes and other proteins designed to kill the snake's prey and begin digesting it even before it is swallowed. It is continually flicking in and out gathering odor molecules from the air. Some snakes, like rattlesnakes and copperheads, are called pit vipers . They have a specialized organ for sensing heat located in a pit on the face between the eye and the nostril. It is said that a rattler can track a mouse by its heat trail long after the mouse has moved away.