Domesticated for hundreds of years in Tibet, yaks are extremely useful to humans, who utilize the bovines in a variety of ways. The hairy tails of the animals, for instance, are used as fly swatters in some parts of the world, and their hides are commonly utilized as leather. Yaks also frequently serve as beasts of burden, as well as sources of meat and milk. The most luxurious item that is derived from yaks, however, may be considered the unusually soft, warm wool of their undercoats that can be spun into a cashmere-like fiber used to fabricate sweaters, coats, and similar items.