How it does so no one quite knows. But the very same animal which is brown all over as it sits upon a branch will become green all over if you put it among leaves. The last thing at night, probably, you will find that it is gray. Next day, perhaps, brown spots will appear upon its body, and pinkish stripes upon its sides. And occasionally it may be violet, and sometimes yellow, and sometimes nearly black. So that if you were to go and look at a chameleon, and then go and look at it again half an hour afterward, you might very likely take it for a wholly different animal!
Then the chameleon has very odd habits. If it is annoyed, for example, it puffs out its body in the most extraordinary way till it is nearly double its ordinary size and its skin is stretched almost as tight as the parchment of a drum. When it is caught it hisses like a snake. And really it must be the very laziest creature on earth. If it lifts a foot into the air it will often wait for quite a minute before it puts it down again, and for two or even three minutes more before it takes a second step. Then it always has to rest for some little time after uncoiling its tail from a branch, while when it coils it round another it stops and rests again. It will hardly travel two yards, in fact, in a day.
Chameleons are found in many parts of Africa and Asia, and also in Southeastern Europe.
CHAPTER XXVIII
SNAKES
There are a great many different kinds of snakes; but before we read about some of them, we must tell you some thing about the wonderful way in which their bodies are made.
In the first place, then, remember that snakes have a very large number of those sections or pieces forming the spine which we call vertebræ. We ourselves have only thirty-three of these little parts when we begin life, and twenty-six afterward; this difference in number being caused by the fact that five of the joints very soon unite into a bony mass at the lower end, which we call sacrum, while four more unite into another, which we call the coccyx. But some snakes have hundreds of these vertebræ. The boas, for example, have no less than three hundred and four!
In the next place, remember that all these vertebræ are fastened together by what we call ball-and-socket joints. That is, there is a round knob at the back of each vertebra which fits into a socket in front of the vertebra behind it. This gives to the spine of a snake great strength, for a vertebra cannot be forced out of its place without breaking the vertebra behind it. And it also allows the spine to be curled and twisted about in almost any direction; so that a snake can easily coil up its body like a spring, or even tie it into a knot.
Then, remember that a snake has a great many ribs. We have twelve pairs of these important bones, most of which are jointed to the breast-bone in front. But a snake may have as many as two hundred and fifty-two pairs of ribs, while it has no breast-bone at all; so that the tips of all the ribs are free. And every rib is fastened to a vertebra of the spine by a ball-and-socket joint, just like those which fasten the vertebræ themselves together. Besides this, there are no less than five separate sets of muscles connected with the ribs, so that the snake can move those bones about quite easily.