The Yak, or grunting Ox, as it is sometimes called from the peculiar grunt which it makes, is a native of the high table-lands of the interior of Asia, to the north of India—'the roof of the world,' as the country is often called. It is a large animal of the ox kind, with a massive head and front, and it is covered entirely with long hair which reaches almost down to its hoofs. It has large, wide-spreading horns, ending in sharp points, and its shoulders are high and almost humped. Its long tail, unlike the tail of the ox, the buffalo, and the bison, is covered with long, silky hair, reaching to the ground. When the animal is killed, this tail is often mounted in an ivory or metal handle, and used by Indian princes as a fly-whisk. The yak's colour is usually black or a very dark brown, but sometimes it is white, and the hair on its shoulders hangs thick and long, like the mane of a lion.

In Thibet the yak is, perhaps, the most useful animal to be found in the country. It is hardy and strong, and thrives upon the short grass growing in the sheltered valleys of the lofty Himalaya and Kuen Luen mountains, at a height where the air is too cold and the ground too rugged and bare for most animals, especially domesticated ones. Though horses and sheep are domesticated by the Thibetans, the yak in many respects replaces them both, besides serving the uses of oxen or cows in other places. Large herds of yaks are driven from place to place by the wandering Thibetans, who pitch their black tents where there is pasturage for their flocks. These people live very largely upon the milk of their yaks, and upon the butter which they make from it. They have a great liking for tea, which comes from China in the form of blocks or bricks, which they break up as they require them. When the tea is boiling in the kettle, they put in large quantities of milk and butter, and even salt, and though the mixture is one which would be very disagreeable to a European, it is enjoyed by the Thibetans, and is no doubt made much more nourishing by the addition of the nutritious milk and butter. The flesh of the yak is considered to be excellent food, and is eaten by those Thibetans who can afford to do so. But a small wandering tribe cannot often kill a yak or a sheep for food, because they cannot eat the whole of the flesh while it is fresh, and thus a portion is wasted.

The long hair of the yak, like the wool of goats and sheep, is suitable for spinning into thread and weaving into cloth. The Thibetans spin large quantities of yak's wool, and some of it they weave, but much of the weaving is done by the Chinese, who sell the cloth back to the Thibetans. Of this cloth the Thibetans make not only their clothes, but also the large tents under which so many of them live. As the wool is not washed, bleached, or prepared in any way before it is spun and woven, the cloth retains the natural greasiness of the wool, which renders it quite water-proof, and thus makes it an excellent material for tents. Even the ropes which sustain the tents are made of yak's wool. The skin, too, of the yak, when prepared in the native way, makes a very good soft leather.

The yak is also used as a beast of burden. In Ladakh it is harnessed to carts, and made to draw ploughs, but in other places it is usually loaded with packs. In Thibet a clumsy wooden pack-saddle is laid upon the yak's back, and the packs are fastened upon each side of it. Though at times restless, the yak is very sure-footed and plodding, and does a fair amount of work considering the nature of the country. An English traveller, who once drove a pair of loaded yaks in Thibet, noticed that they showed a great reluctance to go any way but their own. By-and-by he found that they were selecting the way, which, although it was considered to be a high road, was only marked here and there by a few footprints. So long as he allowed the yaks to go their own way, they went on willingly, and the traveller soon discovered that it was best to leave them alone and simply follow them. Once or twice when he had lost the track, the yaks led him back to it.

Not only are yaks used for draught and for carrying loads, but they are also ridden, a special saddle being then used. Along the roads between Pekin and Lhassa, a yak will carry its rider twenty miles a day, it is said, or it will carry a load ten miles. Much quicker journeys may be made, however, by taking fresh yaks at certain posts or stages. In this way the traveller already referred to was able to ride one hundred and seventy-five miles in five days, the two longest days' journeys being forty-five and forty-two miles respectively.