Rattlesnakes are pit vipers, snakes having a hollow, or pit, between the eye and the nose on each cheek. The pits, which are sensitive to heat, help the snakes find prey and strike precisely in the dark. The rattle consists of a number of interlocking horny compartments. When disturbed, a snake vibrates its tail and the rattle gives off a vibrant chi chi chi chi.

The rattlesnake has two long, hollow fangs at the front of its upper jaw. Ducts connect the fangs to two venom glands at the back of the head. When the fangs pierce a victim, muscles about the glands contract and inject venom into the wound.

When a rattlesnake prepares to strike, its jaws open to form almost a straight line. This causes the fangs, normally folded back against the roof of the mouth, to point forward. A striking snake forms the fore part of its body into an exaggerated S curve and then straightens the curve, stabbing the victim with its fangs.

Look! This snake is ready to strike. At the end of its tail is a hard, horny rattle. Listen! A dry, rattling buzzzz warns you to stay away! It is the rattle, and its warning sound gave the rattlesnake, or rattler, its name.

A rattlesnake’s rattle is made up of rings of thick, dry scales that are loosely joined together. When a rattler shakes its tail, the rings rattle against one another. If you ever hear that sound, watch out!

Many people believe that they can tell the age of a rattlesnake by counting the rings in its rattle. But this is not true.

Each time a rattlesnake sheds, a new ring is added to the base of the rattle. This means that rattlers may get two to four new rings a year. But rattlers also lose rings as the old ones at the tip of the rattle wear down and fall off.

Some species of rattlesnakes live in deserts, others in swamps, woods, or rocky places. Where freezing temperatures occur, rattlesnakes, usually in tangled masses, spend the winter in animal burrows, caves, rock cavities, or other comparatively warm places.

Rattlesnakes give birth to living young. The young are venomous and can take care of themselves from birth. A snake grows a new rattle each time it sheds its skin. However, the age of a snake cannot be told from the number of rattles because the rattles tend to break off and the skin is shed irregularly.

Female rattlesnakes give birth to live young. A group of newborn rattlers is called a clutch.

A mother rattler leaves her clutch shortly after the baby rattlers are born. Young rattlers can already care for themselves. They are able to find their own food. And they are already dangerous, because rattlesnakes are poisonous at birth.

Young rattlers, however, must still watch out for danger. Birds, animals, and even other snakes will swallow up baby rattlers.

Rattlesnakes feed chiefly on rabbits and rodents such as rats, mice, gophers, and prairie dogs. Their chief enemies are human beings; king snakes and other constricting snakes; and owls, hawks, roadrunners, and coyotes.

Snakes have special sense organs to help them find their prey.

With a flick of its tongue, a rattlesnake can tell if a tasty meal is near. The snake’s tongue picks up animal smells from the air. The tongue then delivers the smells to a sense organ in the roof of the snake’s mouth. This organ, called the Jacobson’s organ, is very sensitive to smells. It works along with the snake’s nose to help the snake follow an animal’s scent.

Some snakes, like rattlesnakes, have another way of finding prey. These snakes have heat-sensing pit organs on the sides of their heads. All warm-blooded animals give off body heat. The pit organs sense this heat and help snakes track their prey.

If you just look at a snake, you may think it is wet and slimy. But this is not true. Rattlesnakes, like other snakes, have cool, dry, scaly skins.

Most snakes have scales that overlap and stretch apart. The patterns and colors on a snake come mainly from special color cells in the deep layers of a snake’s skin. Brown, black, and yellow are common colors for rattlesnakes. These colors help rattlers blend in with their surroundings.

All snakes have two layers of skin—an inner layer of growing cells and an outer layer of dead cells. As snakes grow, they molt, or shed, the outer layer of skin. A snake begins to molt by rubbing loose the skin around its mouth and head. Then it crawls out of its skin!

Most rattlesnakes molt two to four times a year. Young snakes may shed more often because their bodies are growing more quickly.

Snakes have remarkable skeletons under their scaly skins. They have about 150 to over 430 vertebrae (VUR tuh bray), the small bones that make up a backbone. Humans have only 33! Each snake vertebra has a pair of ribs and as many as 24 small muscles attached to it. All these bones and muscles make it easy for a snake to bend around and around.

Snakes also have unusual bones in their heads. The jaw bones are only loosely attached to each other and to the rest of the snake’s skull. This allows the two sides of a snake’s mouth to move separately. It also lets a snake open its mouth wide enough to swallow a meal bigger than its head!

Most of a snake’s inner organs are long and slender to fit inside its skeleton. But just like its mouth, a snake’s stomach has to be able to handle big, bulky food. It has to really stretch to hold and digest a snake’s meal.

Snakes have four main ways to travel. The most common is an S-shaped crawl. To do this, a snake wriggles from side to side, pushing against things so that it can move forward.

To climb trees, snakes push and pull their way. First, a snake coils and anchors the back half of its body and pushes the front half forward. Then the snake anchors the front half and pulls up the back half.

Sidewinding helps snakes cross hot desert sands. Here, a snake leaves its head and tail on the ground while it lifts and throws its body to the side. The snake then moves its head and tail in line with the body.

Snakes also move with a forward crawl. Stretching its body out in a straight line, a snake tightens and relaxes its muscles so that its scutes (SKYOOTZ), or belly scales, push and pull along the ground.