Читать книгу The Human Side of Animals - Royal Dixon - Страница 7

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"She was a gordian shape of dazzling line,

Vermilion-spotted, golden, green and blue;

Striped like a zebra, freckled like a pard,

Eyed like a peacock, and all crimson barr'd,

And full of silver moons, that, as she breathed,

Dissolved, or brighter shone, or interwreathed

Their lustres with the glorious tapestries. … "

—Keats (on Lamia, the snake).

The art of concealment or camouflage is one of the newest and most highly developed techniques of modern warfare. But the animals have been masters of it for ages. The lives of most of them are passed in constant conflict. Those which have enemies from which they cannot escape by rapidity of motion must be able to hide or disguise themselves. Those which hunt for a living must be able to approach their prey without unnecessary noise or attention to themselves. It is very remarkable how Nature helps the wild creatures to disguise themselves by colouring them with various shades and tints best calculated to enable them to escape enemies or to entrap prey.

The animals of each locality are usually coloured according to their habitat, but good reasons make some exceptions advisable. Many of the most striking examples of this protective resemblance among animals are the result of their very intimate association with the surrounding flora and natural scenery. There is no part of a tree, including flowers, fruits, bark and roots, that is not in some way copied and imitated by these clever creatures. Often this imitation is astonishing in its faithfulness of detail. Bunches of cocoanuts are portrayed by sleeping monkeys, while even the leaves are copied by certain tree-toads, and many flowers are represented by monkeys and lizards. The winding roots of huge trees are copied by snakes that twist themselves together at the foot of the tree.

In the art of camouflage—an art which affects the form, colour, and attitude of animals—Nature has worked along two different roads. One is easy and direct, the other circuitous and difficult. The easy way is that of protective resemblance pure and simple, where the animal's colour, form, or attitude becomes like that of its habitat. In which case the animal becomes one with its environment and thus is enabled to go about unnoticed by its enemies or by its prey. The other way is that of bluff, and it includes all inoffensive animals which are capable of assuming attitudes and colours that terrify and frighten. The colours in some cases are really of warning pattern, yet they cannot be considered mimetic unless they are thought to resemble the patterns of some extinct model of which we know nothing; and since they are not found in present-day animals with unpleasant qualities, they are not, strictly speaking, warning colours.

Desert animals are in most cases desert-coloured. The lion, for example, is almost invisible when crouched among the rocks and streams of the African wastes. Antelopes are tinted like the landscape over which they roam, while the camel seems actually to blend with the desert sands. The kangaroos of Australia at a little distance seem to disappear into the soil of their respective localities, while the cat of the Pampas accurately reflects his surroundings in his fur.

The tiger is made so invisible by his wonderful colour that, when he crouches in the bright sunlight amid the tall brown grass, it is almost impossible to see him. But the zebra and the giraffe are the kings of all camouflagers! So deceptive are the large blotch-spots of the giraffe and his weird head and horns, like scrubby limbs, that his concealment is perfect. Even the cleverest natives often mistake a herd of giraffes for a clump of trees. The camouflage of zebras is equally deceptive. Drummond says that he once found himself in a forest, looking at what he thought to be a lone zebra, when to his astonishment he suddenly realised that he was facing an entire herd which were invisible until they became frightened and moved. Evidently the zebra is well aware that the black-and-white stripes of his coat take away the sense of solid body, and that the two colours blend into a light gray, and thus at close range the effect is that of rays of sunlight passing through bushes.

The arctic animals, with few exceptions, are remarkable for imitating their surroundings; their colour of white blends perfectly with the snow around them. The polar bear is the only white bear, and his home is always among the snow and ice. The arctic fox, alpine hare, and ermine change to white in winter only, because during the other seasons white would be too conspicuous. The American arctic hare is always white because he always lives among the white expanses of the Far North. Both foxes and stoats are carnivorous and feed upon ptarmigan and hares, and they must be protectively coloured that they may catch their prey. On the other hand, Nature aids the prey by providing them with colours that enable them to escape the attention of their enemies.

The young of many of the arctic animals are covered with fluffy white hair, so that while they are too young to swim they may lie with safety upon the ground and escape the attention of polar bears; but in the antarctic regions, where there are few enemies to fear, the young seals, for instance, are exactly the colour of their parents.

The most remarkable exception of mimetic colouring among the animals of the polar regions is the sable. Throughout the long Siberian winter he retains his coat of rich brown fur. His habits, however, are such that he does not need the protection of colour, for he is so active that he can easily catch wild birds, and he can also subsist upon wild berries. The woodchuck of North America retains his coat of dark-brown fur throughout the long, cold winters. The matter of his obtaining food, however, is easy, for he lives in burrows, near streams where he can catch fish and small animals that live in or near the water.

A number of the old-school naturalists believed that when an animal's colouring assumed the snowy-white coat of its arctic surroundings, this was due to the natural tendency on the part of its hair and fur to assume the colourings and tints of their habitat. This, however, is absolutely false; and no better proof of it can be offered than the case of the arctic musk-ox, who is far more polar in his haunts than even the polar bear, and is therefore exposed to the whitening influence of the wintry regions more than the bear. Yet he never turns white, but is always brown. The only enemy of this northern-dweller is the arctic wolf, and against this enemy he is protected by powerful hoofs, thick hair, and immense horns. He does not need to conceal himself, and therefore does not simulate the colour of his surroundings.