THE RANGE OF ANIMAL DIET.
T,IEUTENANT PEARY, discussing the hardships of Arctic travel, refuses to admit that living on Esquimaux - diet is any hardship at all. On the contrary, he holds that conformity to the food and habits of indigenous peoples is the safest course for an explorer, and that "fat and lean" whale, or seal, eaten raw in alternate bites, makes rather an appetising meal in high latitudes. Moat people would prefer to do their exploring within reach of the comforts of the Fram's ' store-cupboard, so feelingly described by Dr. Nansen. But the experience of Lieutenant Peary and his wife, like that of many Arctic travellers before them, is
• evidence that the human digestion can cope with a potent change of diet when the change of climate and temperature corresponds.
It is self-evident that in the ease of different human races the greater the range of diet the better chance of survival accrues. The districts of India where the population will only eat rice are at a disadvantage in times of scarcity compared with others which affect no single food grain. Famine is much less common among " omnivorous " races than among those which are almost parasitic on a single plant like the banana or the potato. In spite of prejudice, which even in this country would make the lower classes more willing to forego a portion of their weekly meat-supply than to eat rye-bread in place of the wheaten loaf, the tendency everywhere is to increase the range and variety of food.
Among animals the same tendency can be traced. It appears most noticeably in domesticated species, but it can be traced amongst those which are wild, and in regions where evidence of its force as a working law is given by the very small number of creatures now found which live on a single item of food. In the ease of domesticated animals the range of diet is often extended by compulsory detainments in regions in which they are forced to endure the winter which otherwise they would have avoided by migration.
The northern range of the horse and ox now far exceeds the natural food-limit. The Shetland pony could always pick up a bare living, but the Iceland pony has daring the winter absolutely no natural food-supply. A few
are taken into the houses, but the greater number are turned loose by their owners, and have for sole support sea-weed and the heads of dried cod. The Norwegian cow, spending the winter inside the Arctic circle, was formerly fed largely on soup made out of boiled fishes' heads, and the diet seems to have agreed with them. If any one doubts the capacity of extending their food-range possessed by grass- eating creatures like cattle and sheep, and the scarcely less graminivorous horse, which has, however, a strong tendency, inherited from some remote ancestor, to eat bark and shoots like a rhinoceros, he need only run over the list of modern cattle-foods. Since the days when the Irishman had not learnt to make hay, and all his cattle were consequently killed off by Elizabeth's soldiers in the low valleys to which they were driven for food in winter, the cow has added to her menu hay, ensilage sweet and sour, turnips, sugar beet, Indian corn, cocoa cake, cotton-seed cake, rape-seed cake, locust beans, sugar, and "grains." Besides these, she has learnt to eat and prefer cooked food served warm, to raw food eaten cold, and before long will probably be taught to supplement her cabbage and grass with "cow-biscuits," specially prepared to increase her yield of butter.
Horses, though training beat on hay and oats, now eat cooked food, a mixture of hay, bran, vegetables, and corn being steamed and served up in most of the great London stables; and the only domestic creature whose tendency to enlarge its food-range is discouraged is the pig, not because it is bad for the animal, but because we desire by limiting its choice of food to extend our own. For our own purposes we have induced the dog to become largely a vegetable feeder, greatly to the advantage of its health in confinement, and by the substitu- tion of the uniform " dog-biscuit " for table-scraps or meat have given him a mixture of meal and dates, which is as agreeable to crack as a bone. Among the more highly organised creatures " single-food " animals are scarce and growing scarcer. There is evidence that the mute swan once fed almost entirely on sub-aquatic grasses. At Abbotsbury, when the ice destroyed the grass growing at the bottom of the lagoon, the half-wild swans refused to touch any other food, and starved in hundreds. Now they have learnt to eat grain, just as the Thames swans have learnt to eat bread and the grain which falls from barges. Probably the Abbotsbury swans were the last of their species in England which were "single-food" animals, and with their conversion the exten- sion of the range of diet is completed.
Reindeer feed almost entirely on mosses and lichen. It is still matter for doubt whether they can be acclimatised in this country, though experiments are being made to that end. If they cannot, an extension of the species, even though in domestication, will be prevented by their limited food-range. The moose feeds entirely on the bark and twigs of trees. But this is partly due to the height of its fore-legs and the short- ness of its neck, which make it almost impossible for it to graze. When fed from a manger the moose takes readily to ordinary cattle-food. Seals were long considered to live wholly on fish. The supply is so varied as well as abundant, and the seals so active, that it might be thought that there was little to induce them to seek a change. Yet Mr. Trevor-Battye when on Kolguev watched a seal catching ducks, with such persistence and success that there can be little doubt that the seal has extended its dietary from fish to fowl. Instances of the converse are the great fishing owls, which being provided with an equipment equally suited for killing birds and small animals, are by preference catchers of fish. Instances of carnivora developing a concurrent taste for vegetable food are uncommon. The most curious instance the writer has known was that of a Scotch deerhound, which was so fond of peaches that it would stand on its hind-legs to pluck those it could not reach when standing on all fours. The Australian Colonies present the three most striking instances of the tendency to extend the food-range in the direction of flesh diet. The often-quoted case of the large New Zealand parrot which took to sheep-killing is the most striking. But the feral pigs of the Colony are said to be very destructive to young lambs, and in 1833 in Australia throughout a large district the sheep became not only carnivorous but cannibal. The sheep of the Murrambidgee country became addicted to eating a salt-impregnated earth found on the runs, and after some time became thin and emaciated. They then attacked the new-born lambs, and devoured such numbers
that in one flock only four hundred were left out of twelve hundred. Some of the squatters applied for leave from the Government to move to other runs not yet taken up. Even the shepherds were attacked by the sheep when rescuing the lambs, and their clothes bitten. This morbid derange- ment of the instincts of the sheep, which was noted on many runs in the district, was never satisfactorily accounted for, but was generally attributed to the eating of the salt- impregnated earth. Of English birds, one, generally regarded as feeding entirely on vegetables and grain, occasionally varies its diet by animal food. This is the tame pigeon, which has been noticed after rain to eat earth-worms on lawns as eagerly as a thrush. This addition to its usual food is probably due to the absence in the diet generally given to the birds of some element which pigeons find in the mixed seeds and leaves which they eat when wild.
The flesh-eating habits of modern rooks in the North of England and Scotland has recently been the subject of a chorus of complaints from game-preservers and farmers. The rooks are, however, largely the victims of circumstance. The decrease of arable land, during the cultivation of which they found abundance of animal food, has forced the rooks to find a substitute, and this comes to hand in the form of young rabbits, pheasants, and chickens. In the corn countries of the United States the sparrow grows yearly more dependent on grain, and less insectivorous than his European reputation justifies, and in this country two consecutive severe winters made the tits take to bird-killing with an aptitude that shocked their patrons in English gardens. Highly specialised forms, such as the ant-eaters, the moles, and the leaf-eating sloths, must almost of necessity confine themselves to the food which they are "by inten- tion " adapted to consume. But even the woodpecker and the wryneck, with claws specially adapted for scaling tree-trunks, and a beak formed to quarry rotten wood, are constantly seen feeding on the ground, mainly engaged in ravaging ant- hills; and kingfishers, scarcely modified from the shape of those which hover over English streams, dart with equal pre- cision on the butterflies and beetles of tropical woods. Judging by the scarcity of the "single-food" creatures, and the low place in the scale which they occupy, extension of the range of diet is almost a necessary law of. their survival. Ant-eaters, sloths, and caterpillars may confine themselves to one article of food ; but the more intelligent animals, like the higher races of man, have learnt better. One almost wonders whether the excuse of the Congo tribe who brought no palm- wine to the Belgian officers was true. They alleged that "the elephants had drunk it all."
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