Читать книгу The Human Side of Animals - Royal Dixon - Страница 9
American Museum of Natural History, New York THE ZEBRA IS ONE OF THE CLEVEREST OF CAMOUFLAGERS. THE BLACK-AND-WHITE STRIPES OF HIS BODY GIVE THE EFFECT OF SUNLIGHT PASSING THROUGH BUSHES.
ОглавлениеMimetic resemblances are worked out with great difficulty, except in such cases as the nocturnal animals, which simply become one with their surroundings. Mice, rats, moles, and bats wear overcoats that are very inconspicuous, and when suddenly approached they appear almost invisible. Some of the North American Indians claimed that buffaloes made their calves wallow in the red clay to prevent them from being seen when they were lying down in the red soil.
The kinds of protection from these mimetic resemblances are many and varied: the lion, because of his sandy-colouring, is able to conceal himself by merely crouching down upon the desert sands; the striped tiger hides among the tufts of grass and bamboos of the tropics, the stripes of his body so blending with the vertical stems as to prevent even the natives from seeing him in this position. The kudu, one of the handsomest of the antelopes, is a remarkable animal in several ways. His camouflage is so perfect that it gives him magnificent courage. With his spiral horns, white face, and striped coat tinted in pale blue, he is almost invisible when hiding in a thicket. The perfect harmony of his horns with the twisted vines and branches, and the white colourings with blue tints in the reflected sunlight conceal him entirely.
The snow-leopard, which inhabits Central Asia, is stony-grey, with large annular spots to match the rocks among which he lives. This colouration conceals him from the sheep, upon which he preys; while the spotted and blotchy pattern of the so-called clouded tiger, and the peculiarly-barred skin of the ocelot, imitate the rugged bark of trees, upon which these animals live.
One of the most unusual and skilled mimics is the Indian sloth, whose colour pattern and unique eclipsing effects seem almost incredible to those unfamiliar with the real facts. His home is in the trees, and he has a deep, orange-coloured spot on his back, which would make him very conspicuous if seen out of his home surroundings. But he is very clever, and clings to the moss-draped trees, where the effect of the orange-coloured spot is exactly like the scar on the tree, while his hair resembles the withered moss so strikingly that even naturalists are deceived.
Henry Drummond must have known the animal world rather well when he remarked that "Carlisle in his blackest visions of 'shams and humbugs' among humanity never saw anything so finished in hypocrisy as the naturalist now finds in every tropical forest. There are to be seen creatures, not singly, but in tens of thousands, whose every appearance, down to the minutest spot and wrinkle, is an affront to truth, whose every attitude is a pose for a purpose, and whose whole life is a sustained lie. Before these masterpieces of deception the most ingenious of human impositions are vulgar and transparent. Fraud is not only the great rule of life in a tropical forest, but the one condition of it."
Many of the larger cats live in trees, and most of them have spotted or oscillated skins, which aid them in hiding among foliage plants. The puma who wears a brown coat is an exception, but it must be remembered that he does not need the kind of coat his fellow friends wear. He clings so closely to the body of a tree while waiting for his prey as to be almost invisible.
This phenomenon is true throughout the animal world. Everywhere does Nature aid in escape and capture. Only those skilled in the ways of the wild fully realise how conspicuous amidst foliage, for instance, would be a uniform colouration. A parti-coloured pattern is extremely deceptive and thus protective, and for this reason one seldom sees in Nature a background of one colour; and since the large majority of animals need concealment, it is necessary for them to be clothed in patterns that vary.
These variations are especially noticeable in young animals, and furnish them with a mantle that is practically invisible to predatory enemies during the time they are left unprotected by their parents. These protective mantles often differ strikingly in pattern and colouration from those of their parents, and indicate that the young animals present the colouration and pattern of their remote forbears. It might even be said that "the skins of the fathers are thrust upon the children, even unto the third and fourth generation!" In fact, it is quite probable that they give through this varying colouration the "life-history" of their family.
In all hoofed animals—antelope, deer, horses—the protective colouration is also adapted to habitat and environment. Most deer belong to the forest, carefully avoiding the open deserts and staying near water. They live chiefly in the jungle or scrub, and are usually spotted with red and white in such a way as to be almost invisible to a casual observer; some, however, that live in the very shady places are uniformly dark so as to harmonise with their surroundings. The wild horses and asses of Central Asia are dun-coloured—corresponding exactly to their sandy habitat.
The Shakesperian conception of the human world as a stage may be paralleled in the animal world. Animals, like human beings, have all a definite rôle to play in the drama of life. Each is given certain equipment in form, colour, voice, demeanour, ambitions, desires, and natural habitat. Some are given much, others but little. Many have succeeded well in the art of camouflage while endeavouring to make a success in life. This success has brought the desired opportunity of mating, rearing young, bequeathing to them their special gifts and living in ease and comfort.
One of the most successful and striking cases of protective colouration in young animals is found in wild swine. Here there is longitudinal striping which marks them from head to tail in broad white bands, over a background of reddish dark brown. The tapirs have a most unique form of marking. It is similar in the young of the South American and Malayan species. Their bodies are exquisitely marked in snow-white bars. At their extremities these bars are broken up into small dots which tend to overlap each other. During the daytime these young animals seek the shade of the bushes and as the spots of sunlight fall upon the ground they appear so nearly one with their environment as to pass unnoticed by their enemies. The adults, however, vary greatly one from another in colouration. The American species is self-coloured, while the Malayan has the most unique pattern known to the animal world. The fore-quarters, the head, and the hind-legs are black, while the rest of the body from the shoulders backwards is of a dirt-white colour.
It has been observed by all students of Nature that bold and gaudy animals usually have means of defending themselves that make them very disagreeable to their enemies. They either have poisonous fangs, sharp spines, ferocious claws, or disagreeable odours. There are still others that escape destruction because of the bad company with which they are associated by their enemies.
The reptiles offer us many good examples of mimicry. Most arboreal lizards wear the colour of the leaves upon which they feed; the same is true of the whip-snakes and the tiny green tree-frogs. A striking example of successful camouflage is found in the case of a North American frog whose home is on lichen-covered rocks and walls, which he so closely imitates in colour and pattern as to pass unnoticed so long as he remains quiet. I have seen an immense frog, whose home was in a damp cave, with large green and black spots over his body precisely like the spots on the sides of his home.