Kangding County of Ganzi Tibetan Autonomous Prefecture in Sichuan Province
Domesticated yaks have been kept for thousands of years, primarily for their milk, fibre and meat, and as beasts of burden. Their dried dung is an important fuel, used all over Tibet, and is often the only fuel available on the high treeless Tibetan plateau. Yaks transport goods across mountain passes for local farmers and traders as well as for climbing and trekking expeditions. "Only one thing makes it hard to use yaks for long journeys in barren regions. They will not eat grain, which could be carried on the journey. They will starve unless they can be brought to a place where there is grass." They also are used to draw ploughs. Yak milk is often processed to a cheese called chhurpi in Tibetan and Nepali languages, and byaslag in Mongolia. Butter made of Yaks' milk is an ingredient of the butter tea that Tibetans consume in large quantities, and is also used in lamps and made into butter sculptures used in religious festivities. Yaks grunt, and unlike cattle are not known to produce the characteristic bovine lowing sound.