So by the waterside, on the land, and among the trees, the lizard tribe still flourish in spite of higher animals; and just as we found some legless kinds among the amphibia burrowing in the ground, so here, too, we find legless lizards, some with small scaly spikes in the place of hind legs, others, like the glass-snake of America[82] and our English slowworm[83] (or blindworm), which have no trace of feet outside the skin, but glide along under grass and leaves, eating slugs and other small creatures, though they are true lizards with shoulder bones and breastbones under the skin.
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Here, then, we seem to be drifting along the road to snake-life, but we must halt and travel first in another direction, upwards to a higher group of animals, which may almost be called gigantic flesh-eating lizards, though they are far more formidable and highly-organised creatures. These are the Crocodiles, and no one looking at them can doubt for a moment that they at least are well armed, so as to have an easy time of it without much exertion. Huge creatures, often more than twenty feet long, with enormous heads and wide-opening mouths, holding more than thirty teeth in each jaw, they look formidable indeed as they drag their heavy bodies along the muddy banks of the Nile, their legs not being strong enough to lift them from the ground. Their whole body is covered with strong horny shields, and under these shields, on the back, are thick bony plates, which will turn even a bullet aside, and quite protect the crocodile from the fangs of wild beasts. Their eyelids are thick and strong, and they have a third skin which they can draw over the eye sideways like birds; their ears, too, have flaps to cover them, and their teeth are stronger and more perfect than any we have yet seen, for they are set in sockets, and new ones grow up inside the lower part of the old ones as they are broken or worn away.
Fig. 25.
The Nile Crocodile.—(Tristram.)
But it is in the water that we see them in their full strength; there they swim with their webbed feet and strokes of their powerful tail, and feed upon the fishes and water animals—monarchs of all they survey. Nor is the crocodile content with mere fish-diet. Often he will lie with his nostrils just above the water and wait till some animal—it may be a goat, or a hog, or even a good-sized calf—comes to drink, then he will come up slowly towards it, seize it in his formidable jaws, or sometimes strike it with his powerful tail, and drag it under water to drown. For he himself can shut down his eyelids and the flaps over his ears, and he has a valve in the back of his throat which he can close, and prevent the water rushing down his open mouth; and after a while he rises slowly till his nostrils are just above the water, and he can breathe freely while his victim is drowning, because his nose-holes are very far back behind the valve. Then when it is dead he brings it to shore to tear it to pieces and eat it.
Thus the crocodiles of the Nile and the Ganges, the Gavials with their long narrow snouts, and the Alligators of America, with their shorter and broader heads, feed on fish and beasts, and all dead and putrid matter, acting as scavengers of the rivers; while they themselves are almost free from attack, except when tigers fall upon them on land. But it is the young crocodiles which run the most risks when they come out of the small chalky eggs which have been hatched in the warm sand of the shore. True, their mother often watches over them at this time, and even feeds them from her own mouth; but in spite of her care many of them are eaten in their youth by the tortoises and fishes which they would themselves have devoured by-and-by, if they had lived to grow up; while the monitors, ichneumons, waterfowl, and even monkeys, devour large numbers of crocodiles’ eggs.
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And now, if we were to turn our backs upon the great rivers in which these animals dwell, and wander into the Indian jungle or the South American forest, we might meet with enemies far more dangerous and deadly, although they stand much lower in the reptile world. Who would think that the huge boa of South America, and the python and poisonous cobra of India, or even our own little viper, whose bite is often death to its victim, are creatures of lower structure than the harmless little lizard or the stupid alligator? Yet so it is. For Snakes have no breastbone and have lost all vestiges of front legs and shoulder bones, nor have they any hips or hind legs except among the boas and rock-snakes; and even these have only small traces of hips, which carry some crooked bones, ending in horny or fleshy claws, in the place where hind legs ought to be. They have no eyelids (and by this we may know them from the legless lizards), but their skin grows right over the eyes, so that when a snake casts its skin there are no holes where the eyes have been, but only clear round spaces like watch-glasses, in the scaly skin. Their ears have no drum, and are quite hidden under the scales with which their body is so thickly covered that they must feel very little as they glide along. These scales, like those of the lizard, are thickened parts of the outer skin, and if you stretch a piece of snake-skin you can see them lying embedded in it, the clear skin itself showing between.