Snakes have no legs. A snake's body is covered with scales. The scales are made of keratin, the same material as human fingernails. Wide, flat scales on a snake's belly grip the ground like the treads of a tire. This helps the snake move. The most common way snakes move is serpentine movement. The snake bends its body in a series of curves and pushes against surfaces.

In concertina movement a snake coils its body into curves that switch sides, then straightens out to push itself forward. In sidewinding, a snake bends in waves both side to side and up and down. Flying snakes flatten their bodies and glide through the air from tree to tree. Five kinds of snakes can do this, in southern and southeast Asia.

Snakes are cold-blooded. Their body heat depends on the heat around them. Snakes warm their bodies by lying in the sun. In cold weather snakes rest through the winter in a state called brumation, which is like hibernation. Garter snakes usually spend the winter together in groups. They are among the first snakes to wake up in spring.

A snake flicks its forked tongue to pick up chemicals from the air, the ground or the water. A snake's sharpest sense is smell. Some snakes also have heat-sensing pits on the sides of the head. The pits sense the warmth given off by warm-blooded prey. A clear scale over each eye, called a spectacle or eye cap, protects the eye.

Snakes eat other animals, such as mice, rats, fish and frogs. Snakes do not chew their food. They swallow it whole. Stretchy ligaments hold a snake's jaws together loosely, so even wide food can fit. After a big meal a snake does not need to eat again for a long time. Burmese pythons can go four to six weeks between meals.

Many snakes hide and wait for an animal to come close, instead of chasing it. Some snakes, called constrictors, catch food by wrapping their body around an animal and squeezing. A few kinds of snakes, such as rattlesnakes and coral snakes, catch food with venom that they inject through their fangs. A wild snake is best left alone: it will usually go its own way. If one is near a home, a grown-up can call animal control.

Words to know

• keratin: fingernail stuff
• serpentine: curvy snake movement
• constrictors: squeezing snakes
• venom: injected by fangs
• brumation: winter rest
• spectacle: clear eye scale

The short version

Snakes have no legs. They move by bending their bodies in curves and pushing against surfaces, and wide, flat scales on the belly grip the ground. A snake's body is covered with scales made of keratin. Snakes do not chew their food. They swallow their prey whole.

Quick facts

• Snakes have no legs, and their bodies are covered with scales.
• The most common way snakes move is serpentine movement, in a series of curves.
• A snake flicks its forked tongue to pick up chemicals from the air, the ground or the water.
• Snakes warm their bodies by lying in the sun.
• Snakes swallow their prey whole.