And now, if we leave the tortoises and turn to the Lizards, we find them meeting life’s difficulties in quite a different way. Here are no sluggish movements, horny beaks, and strong boxes; but bright-eyed creatures covered with shining scales, their mouths filled with sharp teeth, with which even the small lizards can bite fiercely, and having nimble lissome bodies, which wriggle through the grass or up the trees in the twinkling of an eye. Yet the lizards, as we have

seen, are formed on the same plan as the tortoise, and their scales are thickenings in their outer skin, just as his tortoise-shell is, and not true scales like those of fish. They have learned to hold their own by sharpness and quickness, and are probably the most intelligent of all the cold-blooded animals, though even they are only lively in a jerky way under the influence of warmth. They can breathe more easily than the tortoise, for their ribs rise and fall, drawing in and driving out the air they need; but they are still cold-blooded, for their heart has only three chambers. It is when the bright sun is shining that they love to dart about, chasing the insects upon which they feed; and the joints of their backbone move so easily upon each other that they can twist and turn in all imaginable ways, keeping their heads twisted in a most comical manner when on the watch for flies. Nay, the very vertebræ themselves are so loosely made that they can split in half, and if you seize a lizard by the tail he will most likely leave it in your hand and grow another.

They can live both in dry sandy places, where larger animals cannot find food and water, and in thick underwood, and marshy unhealthy places, where more quickly-breathing animals would be poisoned by the fetid air; and we find them swarming in hot countries in spite of enemies, their scales protecting them from the rough surface of the rocks and trees on which they glide, their feeble legs scarcely ever lifting their body from the object on which they glide rather than walk.

Fig. 24.

Gecko and Chamæleon.

The true land-creepers, like our little Scaly Lizard,[81]

Footnote 81. Zootoca vivipara.

lurk in dry woody places, and on heaths and banks, darting out on the unwary insects. Many of them lay their eggs in the warm sand or earth, but the Scaly lizard carries them till they are ready to break, so that the young ones come out lively and active as the eggs are laid. Others have taken to the water, and among these are the Monitors of Africa and Australia, which feed on frogs and fish and crocodiles’ eggs, and are so strong and fierce that they often drag larger animals under the water. Some are tree and wall climbers, such as the “Geckos,” with thick tongues and dull mottled skins, and they have sharp claws and suckers under their toes, so that they can hang or walk upside down, on ceilings or overhanging rocks, or on the smooth trunks of trees; and they love to chase the insects in the hot sultry nights,

tracking them to their secret haunts. They are far more active than the large gentle Iguanas or Tree-Lizards of South America, from a few inches to five feet long, which may be seen among the branches of the trees of Mexico, their beautiful scales glistening in the sun as they feed on the flowers and fruit. They swarm on all sides in those rich forest regions, scampering over the ground, and then clinging with their claws to the tree-bark as they gradually mount up into the dense foliage; and they have many advantages, for not only can they climb to great heights out of the reach of beasts of prey, but they can also swim well, having been known to fling themselves from the overhanging branches into the water below when danger was near. They do not, moreover, descend as gracefully as the “Flying Lizards” of the East Indies, which have a fold of skin stretched from the lengthened ends of their hinder ribs, so that they sail from branch to branch as they chase the butterflies and other insects.

But the most curious of all tree-lizards is the Chamæleon, with his soft warty skin, his round skin-encircled eyes, his bird-like feet, and his clinging tail. He never hurries himself, but putting forward a leg, at the end of which is a foot whose claws are divided into two bundles, he very deliberately grasps the branch, as a parrot does, loosens his tail, draws himself forward, and then fastens on again with tail and claws; while his eyes, each peering out of a thick covering skin, roll round quite independently of each other, one looking steadily to the right, while the other may be making a journey to the left. What is he looking for? Just ahead of him on a twig sits a fly, but he cannot reach him yet. So once more a leg comes out, and his body is drawn gradually forwards. Snap! In a moment his mouth has opened, his tube-like tongue, with clubbed and sticky tip, has darted out and struck the fly, and carried it down his throat, while the chamæleon looks as if he had never moved. It is not difficult to imagine that such a slow-moving animal, whose natural colour is a brownish green like the leaves among which he moves, would often escape unseen from his enemies. And when light falls upon him, his tint changes by the movement of the colour-cells in his skin, which seem to vary according to the colour of the objects around, whenever he is awake and can see them.

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.

* * * * *

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

Footnote 82. Ophisaurus ventralis.

Footnote 83. Anguis fragilis.

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.

* * * * *

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.

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