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Types of Snakes
Most snakes are like one another in general appearance, but vary a great deal in size and color markings. They move by a wriggling movement which presses the horny plates of the belly against the earth and so thrusts the animal forward.
Snakes swallow their food whole, and, as they frequently eat animals two or three times as wide as themselves, the snake's lower jaw is capable of being stretched sideways to hold the creature it is swallowing.
Some people think that the long, slender, forked tongue of the snake is a sort of sting; but this is not so. The tongue is some kind of very sensitive sense organ.
Many snakes have teeth, but swallow their food whole. Poisonous snakes have no upper teeth and inject venom by means of a pair of fangs, usually at the front of the mouth in the upper jaw: these fangs are hollow teeth, sharp as needles, and when the snake strikes the pressure of penetrating the skin causes the poison to be squirted out from a little bag at the base of the teeth, running down a groove in each fang. A great many snakes are not poisonous, however, and the first important group of these non-poisonous snakes are the constricting snakes.
The boa and python are non-poisonous; they kill their prey by constriction-that is to say, they wrap one or two coils of their body round the victim, which is usually a small mammal or bird, and squeeze it to death! The largest of the boas is the anaconda, which is equally at home in trees or in the water. Its length often exceeds twenty feet.
Other members of this family are the boa constrictor (which like the anaconda lives in South America) and several kinds of python.
Like the boa, the python spends a lot of its time in trees, and is capable of hanging down from tree branches by its tail only.
A great many other snakes are non-poisonous.
One of the more interesting is the egg-eating snake.
The egg is swallowed whole, but when it reaches the snake's gullet, the snake, by tightening the muscles of its neck and by rocking itself backwards and forwards, saws through the egg-shell by rubbing it against its spine. The egg then breaks, and the empty shell is thrown up in the form of a small pellet.
The British grass-snake is another harmless animal. It is a good swimmer, although it spends a great deal of its time on land, and it feeds on small creatures such as worms and insects.
Perhaps we might include in this group some of the tree snakes, which have poison fangs, but being situated at the back of the mouth they are not dangerous to man. Many of these tree snakes are brightly colored and one of these-the Indian flying snake-although it has no special wings like the flying lizard, is capable of gliding. If a flying snake is frightened whilst in a tree, it will fling itself into the air, holding itself rigid; by drawing in its stomach, it produces a hollow in the under surface of its body which checks its fall and enables it to glide.
Probably the most notable poisonous snake is the cobra, which is to be found throughout southern Asia and Africa. The cobra has a hood at the back of the head which is spread out when the snake is surprised or angered and likely to strike. The cobra's bite is deadly.
The African mamba is related to the cobra, and its bite is just as severe; it does not, however, have the hood which is so characteristic of the cobra.
The coral-snake also has a deadly bite, and although small in size this snake is treated with great respect.
One group of snakes has taken to living in the sea. All sea-snakes are poisonous and they feed chiefly on fish, particularly eels.
The viper and rattlesnake have poison fangs which differ from those of others, in that the fangs can be folded flat against the roof of the mouth.
The African puff-adder is typical of this family and one viper -the common adder- is to be found in Britain. It is the only poisonous British snake, and can easily be distinguished by the zigzag black line which runs down its back, although the general color may vary from grey to brown, red, or almost black.
The rattlesnake lives chiefly in North America, and gets its name from the rattle which it shakes with a series of loose horny plates or rings situated at the tip of its tail. Each time the rattlesnake sheds its skin it adds a new ring to its rattle.
The shedding of the snake's skin (called sloughing) happens fairly regularly with all snakes when the old skin is worn or outgrown. By vigorous rubbing the old skin is rolled back from the head, inside out, and the snake slowly works its way free, emerging in a beautiful new coat.