Snakes. Snakes form one of the world’s most successful groups of animals. They live on every continent but Antarctica and number approximately 3,000 different kinds, or species. Most of these live on or under the ground, but some live in trees, and some spend all or part of their lives in the water. Only 400 species are poisonous, and of these, fewer than 50 are dangerous to people. In the United States, only 15 people are killed each year by snakes, compared to the more than 40,000 killed yearly in car accidents. Snakebite is not really a major cause of death anywhere.
Snakes come in two varieties: poisonous snakes and constrictors. Constrictors wait patiently for an opportunity to grab passing prey, quickly wrap themselves around it, and squeeze hard enough to keep the animal from breathing. When the animal has stopped breathing, the snake must swallow it whole, because snake teeth are no good for chewing. Poisonous snakes take a less strenuous approach: they simply use their fangs to inject venom and sit back to wait for the venom to take effect.
Rats, mice, and other vermin are tasty treats to snakes. If not for snakes, we would probably be overrun by these rodents. Some eat eggs, frogs, or even insects. Many snakes can swallow animals that are almost as big as they are. This means that the largest snakes can swallow BIG animals. Record books tell us of an African rock python (weighing no more than 140 pounds) that swallowed an animal that weighed more than 130 pounds!
Most snakes are oviparous. This means they lay eggs, from which the young later hatch. To protect the babies inside them, the eggs are tough and leathery, and the young snakes sometimes have a difficult time breaking out of them. Each baby snake has a sharp bump, called an egg tooth, on top of its snout. This helps the young to cut through the shell. Some snakes give birth to live young. The unborn young are in thin casings, or sacs, inside the mother. They hatch from these egg sacs just before or immediately after birth. These snakes are called ovoviviparous.
Snakes live on every continent except Antarctica. They can be found not only on or under the ground, but also in lakes, rivers, and oceans. Many live in trees—some species in Southeast Asia even glide through the air. Dull colors and geometric patterns help disguise desert snakes while they bury themselves in the sand; bright colors can hide a snake in a lush tropical forest.
Most snakes are harmless to people. The age old fear of snakes, however, still lingers. In fact, the fear of snakes may be greater now than ever before, because so many people who live in cities never get to see many snakes or to learn about them. Our ancestors had the good sense to treat poisonous snakes with a healthy respect, but also to recognize that all snakes are marvelous creatures. We should learn to do the same.