The ancestor of the wild and domestic yak is thought to have diverged from Bos primigenius at a point between one and five million years ago.

Both sexes have long shaggy hair, with a dense woolly undercoat over the chest, flanks, and thighs for insulation against the cold.

The coat is typically black or dark brown, covering most of the body, with a grey muzzle (although some wild golden-brown individuals have been reported).

[6] Wild yaks once ranged up to southern Siberia to the east of Lake Baikal,[12] with fossil remains of them being recovered from Denisova Cave,[13] but became extinct in Russia around the 17th century.

[14] Today, wild yaks are found primarily in northern Tibet and western Qinghai, with some populations extending into the southernmost parts of Xinjiang, and into Ladakh in India.

Small, isolated populations of wild yak are also found farther afield, primarily in western Tibet and eastern Qinghai.

They are most commonly found in alpine tundra with a relatively thick carpet of grasses and sedges rather than the more barren steppe country.

[11] Thubten Jigme Norbu, the elder brother of the 14th Dalai Lama, reported on his journey from Kumbum in Amdo to Lhasa in 1950: Before long I was to see the vast herds of drongs with my own eyes.

The sight of those beautiful and powerful beasts who from time immemorial have made their home on Tibet's high and barren plateaux never ceased to fascinate me.

Somehow once they live together with human beings they seem to lose their astonishing strength and powers of endurance; and they are no use at all as pack animals, because their backs immediately get sore.

[1] Although wild yaks can become aggressive when defending young, or during the rut, they generally avoid humans, and may flee for great distances if approached.

Conflicts with herders themselves, as in preventive and retaliatory killings for abduction of domestic yaks by wild herds, also occur but appear to be relatively rare.

Recent protection from poaching particularly appears to have stabilized or even increased population sizes in several areas, leading to the IUCN downlisting in 2008.