Yak, pronounced yak, is a wild ox of Asia. It inhabits the cold, dry plateaus of Tibet, often more than 16,000 feet (4,870 meters) above sea level. The wild yak stands over 6 feet (1.8 meters) high at the shoulders. But it carries its head low with the nose almost touching the ground. It may weigh from 1,100 to 1,200 pounds (499 to 544 kilograms). The yak is covered with black or brownish-black hair. The hair is especially long and silky on shoulders, flanks, and tail. The yak is agile in spite of its bulk and its heavy forequarters. It can slide down icy slopes, swim swift rivers, and cross steep rock slides. If forced to defend itself, it charges furiously. Excessive hunting has resulted in the killing of so many wild yaks that the animal is in danger of extinction. The domestic yak, often called the grunting ox because of the sounds it makes, is the result of many generations of careful breeding. It is often white or piebald instead of black like the wild yak. Smaller and much more docile than the wild yak, it is useful in many ways. As a pack animal, it can carry a heavy load 20 miles (32 kilometers) a day. In Tibet, the yak carries travelers and mail. It provides rich milk. Its flesh is dried or roasted for food. The soft hair of the domestic yak is used to make cloth, and the coarser hair for mats and tent coverings. Saddles, whips, boots, and other articles are made from the hide. The bushy tail of the domestic yak is used as a fly chaser at ceremonial processions in India, and as an ornament for a tomb or shrine. Scientific classification. The yak belongs to the bovid family, Bovidae. It is Bos grunniens.