In addition to this familiar eastern cottontail we have in the United States several other species, as the little marsh-hare and the big water-hare of the Southern States; the large northern varying hare; the arctic hares; the various long-eared, long-legged "jack rabbits" of the Plains and Rocky Mountains; and several lesser species, more or less common on the Pacific coast. The varying hare is so called because, as is the case with several foreign northern hares, its brown summer coat when shed as usual on the approach of winter is replaced by one which is white. CHAPTER XV THE WILD OXEN We now come to a very important group of mammals called ungulates, or hoofed animals, because of the way in which their feet are formed. The oxen, sheep, goats, antelopes, deer, horses, swine, elephants, and rhinoceroses all belong to this order. First let us notice some of the wild oxen. THE GAUR The largest of these is the Gaur, which is found in India. It is a very big animal, sometimes standing more than six feet in height at the shoulder, and as it has long and very powerful horns, it is much dreaded by the natives. As a rule, however, it is a very gentle and peaceable animal, scarcely ever venturing to attack man, and only dwelling in those remote parts of the jungle to which even hunters seldom find their way. The gaur lives in small herds, generally of from ten to twenty in number. Each of these is led by an old bull, and there are generally two or three younger ones, the rest being cows and calves. When the younger bulls grow up they usually fight the old one in order to take his place. For some time he contrives to hold his own; but when at last he is beaten he goes off and lives in the thickets by himself. These solitaries, as they are called, are generally very savage, and will often rush out and attack a passer-by, even when he has not provoked them at all. The gaur is a very wary animal, and sentries are always posted near the herd, in order to give warning of the approach of a foe. When feeding, they are said to stand in a circle with their heads outward, so that they can see in every direction. The old male gaurs are nearly black in color, and the younger ones and the cows reddish brown, while they all have white "stockings" from the knee downward. THE YAK The yak, which lives in Tibet, is something like an ox with great masses of hair on its flanks, limbs, and tail. In color it is blackish brown, with a little white upon the muzzle, and in height is about five feet six inches at the shoulder. The thick fringes of hair do not begin to grow till it is about three months old, and the young calf is covered all over with curly black hair, like a Newfoundland dog.