The key factors that distinguish Tibetan nomadic pastoral areas from cultivated agricultural areas are altitude and temperature, in contrast to most other pastoral areas of the world where the key factor is usually the lack of water. Tibetan nomads prosper at altitudes of 11,000 to 17,000 feet in environments too cold for crop cultivation. Yet at these high elevations there is still extensive and productive grazing land that provides nutritious forage for nomads' herds. The wild yak is the progenitor of all domestic yak populations. The domestication of the wild yak, about 4,000 years ago, was an important factor in the evolution of Tibetan civilization.
Tibetan nomads raise yaks, yak-cattle hybrids, sheep, goats, and horses.
Yaks provide nomads with milk, meat, hair, wool, and hides. Yaks are also used as pack animals and for riding. Dried yak dung is an important source of fuel in a land where firewood is not available. The yak makes life possible for people across much of the Tibetan steppe. Yaks also play an important part in many pastoral rituals and religious festivals.