70 The Naturalist in La Plata.
diminish or increase; the old go, and others with different weapons and a new strategy take their place; and just as a skilful man "fighting the wilderness" fashions a plough from a hunting-knife, turns his implements into weapons of war, and for everything he possesses discovers a use never contemplated by its maker, so does Nature --only with an ingenuity exceeding that of man--use the means she has to meet all contingencies, and enable her creatures, seemingly so ill-provided, to maintain their fight for life. Natural selection, like an angry man, can make a weapon of anything; and, using the word in this wide sense, the mucous secretions the huanaco discharges into the face of an adversary, and the pestilential drops "distilled" by the skunk, are weapons, and may be as effectual in defensive warfare as spines, fangs and tushes.
I do not know of a more striking instance in the animal kingdom of adaptation of structure to habit than is afforded by the hairy armadillo--Dasypus villosus. He appears to us, roughly speaking, to resemble an ant-eater saddled with a dish cover; yet this creature, with the cunning Avhich Nature has given it to supplement all deficiencies, has discovered in its bony encumbrance a highly efficient weapon of offence. Most other edentates are diurnal and almost exclusively insectivorous, some feeding only on ants; they have unchangeable habits, very limited intelligence, and vanish before civilization. The hairy armadillo alone has struck out a line for itself. Like its fast disappearing congeners, it is an insect-eater still,
Some curious Annual Weapons. 71
but does not like them seek its food on the surface and in the ant-hill only; all kinds of insects are preyed on, and by means of its keen scent it discovers worms and larvae several inches beneath the surface. Its method of taking worms and grubs resembles that of probing birds, for it throws up no earth, but forces its sharp snout and wedge-shaped head down to the required depth; and probably while working it moves round in a circle, for the hole is conical, though the head of the animal is flat. Where it has found a rich hunting-ground, the earth is seen pitted with hundreds of these neat symmetrical bores. It is also an enemy to ground-nesting birds, being fond of eggs and fledglings; and when unable to capture prey it will feed on carrion as readily as a wild dog or vulture, returning night after night to the carcase of a horse or cow as long as the flesh lasts. Failing animal food, it subsists on vegetable diet; and I have frequently found their stomachs stuffed with clover, and, stranger still, with the large, hard grains of the maize, swallowed entire.
It is not, therefore, strange that at all seasons, and even when other animals are starving, the hairy armadillo is always fat and vigorous. In the desert it is diurnal; but where man appears it becomes more and more nocturnal, and in populous districts does not go abroad until long after dark. Yet when a district becomes thickly settled it increases in numbers; so readily does it adapt itself to new conditions. It is not to be wondered at that the gauchos, keen observers of nature as they are, should make this species the hero of many of
72 The Naturalist in La Plata.