(MS.Encarta) - Put yourself in the place of a harmless snake. You’re just lying in the grass, minding your own business, when suddenly a great big foot comes crashing down right next to your head. You take off through the grass like greased lightning. In the distance someone screams, “Snake!” Which one should be more afraid, the human or the snake?A snake is simply a long, thin animal. It does not have arms or legs. It crawls along the ground on its belly.
Snakes are reptiles. Like all reptiles, snakes are cold-blooded. They can’t control their own body temperature, and so they have to lie in the sun to get warm and in the shade to get cool.
WHERE DO SNAKES LIVE?
Snakes live almost everywhere in the world. They live in grasslands, deserts, and rain forests. Some snakes live in water. There are no snakes, however, in Ireland, Iceland, Antarctica, or New Zealand. There are more than 2,500 species (kinds) of snakes.
HOW BIG ARE SNAKES?
The world’s smallest snake is about 5 inches (about 13 centimeters) long at full growth and weighs less than 0.1 ounce (less than 2 grams). The largest snakes are the anaconda and the reticulated python. They both can grow as long as 33 feet (10 meters) and can weigh up to 550 pounds (250 kilograms).
DO SNAKES HAVE BONES?
Like other reptiles, snakes are vertebrates—they have a backbone. A snake’s long backbone is made up of small bones called vertebrae. Snakes have between 100 and 400 vertebrae. Humans have just 32 vertebrae.
A snake’s jawbones are not attached to its skull. They are linked together by muscles and stretchy tissues called ligaments. This type of jaw lets a snake open its mouth wide and eat animals that are much larger than its head!
A SNAKE’S SKIN
The dry outer layer of a snake’s skin is made of scales. Scales give a snake its color. The color of some snakes lets them blend into their surroundings and avoid being seen. Some poisonous snakes are brightly colored to warn off enemies.
Snakes regularly shed their skin. First, a new layer of skin forms underneath the old one. Then the snake loosens the skin around its lips. Finally, the snake crawls out of its old skin. A brand new skin takes its place.
SNAKE SENSES
Snakes don’t see or hear as well as other animals. A snake has eyes but no eyelids. They have clear scales over their eyes. Most snakes can see movement, but some snakes are blind.
Snakes do not have ears. They have bones in their heads that can sense low sounds and vibrations.
Snakes have a great sense of smell. A snake flicks out its forked (divided) tongue to collect scents. It doesn’t mean the snake is hungry. The snake pulls its tongue in and sticks the forked tips into a place in the roof of its mouth called Jacobson’s organ. This way of smelling lets snakes find other snakes as well as prey (animals it hunts for food).
Pit vipers, boas, and pythons have small pits on their heads that can sense heat. These pits help a snake sense when a warm-blooded animal is near.
POISONOUS SNAKES
Most snakes will not harm people. Garter snakes and ribbon snakes are harmless snakes. But some snakes can be deadly. They inject a poison called venom when they bite. They use venom to defend themselves or to kill prey.
Poisonous snakes have two big, hollow teeth called fangs. When they bite, the venom comes down through these fangs. Pit vipers keep their fangs folded in their mouths until they are ready to strike. Rattlesnakes are a well-known kind of pit viper. Cobras and coral snakes are also very poisonous.
Spitting cobras do not have fangs. Instead, they spit poison to defend themselves. They aim their venom at the eyes. The venom can cause blindness.
Someone bitten by a poisonous snake should get medical help immediately. Snake venom can be deadly.
BOAS AND PYTHONS
Boas and pythons are kinds of snakes known as constrictors. These snakes have thick bodies and strong muscles. Instead of biting, they wrap themselves around their prey and squeeze. They squeeze so hard that the animal can’t breathe and dies.
HOW DO SNAKES MOVE?
Some snakes move by wiggling and squirming forward. Some snakes make leaping, twisting movements called sidewinding.
Snakes that live in trees coil their tail around a branch. Then they hook their neck into a higher part of the tree and pull the rest of their body up behind them.
WHAT DO SNAKES EAT?
Snakes eat a variety of things: worms, insects, lizards, small mammals, birds, and frogs. Some snakes, such as the Australian bandy-bandy, feed only on other snakes. Other snakes like to eat the eggs of other animals. An adult reticulated python eats larger prey, such as wild pigs, monkeys, and small deer.
Snakes don’t chew their food. They swallow it whole. Their teeth point backward, which helps to keep prey from escaping. Many snakes begin to swallow their prey while it’s still alive. Others kill the animals before eating them.
LIFE CYCLE OF A SNAKE
Most snakes lay eggs. Some sea snakes and snakes that live in cold places give birth to live baby snakes.
Some snakes can begin reproducing at two years of age. Others take slightly longer to mature. Snakes may live for as long as 20 to 30 years.
SNAKES AND PEOPLE
People in Asia and other places kill snakes for meat. Some people make shoes, belts, purses, and other things out of snakeskin. When people build houses and farms, the places where snakes live are often destroyed.
Scientists and other experts fear that some snakes could become endangered if the killing of snakes or the destruction of their habitat (living places) continues. Some countries have laws against killing or selling snakes for their skins or their meat.
