Wild yaks usually form herds of between ten and thirty animas, They are insulated by dense, close, matted under-hair as well as their shaggy outer hair. Yaks secrete a special sticky substance in their sweat which helps keep their under-hair matted and acts as extra insulation. This secretion is used in traditional Nepalese medicine. Many wild yaks are killed for food by hunters in China; they are now considered a vulnerable species.
The diet of wild yaks consists large of grasses and sedges and they also eat a smaller amount of herbs shrubs and mosses, and have been been reported to eat lichen. Historically, the main natural predator of the wild yak has been the Tibetan wolf, but brown bears and now leopards have also been reported as predators in some areas, likely of young or inform wild yaks.
Thubten Jigme Norbu, the elder brother of Tenzin Gyatso, the 14th Dalai Lama, reported on his journey from Kumburn 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. And what a wonderful sight it is to see a great herd of them plunging head down in a wild gallop across the steppes. The earth shakes under their heels and a vast cloud oof dust marks their passage. At nights they will protect themselves from the cold by huddling up together, with the calves in the centre. They will stand like this in a snow-storm, pressed so close together that the condensation from their breath rises into the air like a column of steam. The nomads have occasionally tried to bring up young 'drongs' as domestic animals, but they have never entirely succeeded. 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. their immemorial relationship with humans has therefore remained that of game and hunter, for their flesh is very tasty". - Thubten Norbu, Tibet is My Country.
Wild yaks are primarily found in northern Tibet and western Qinghai (north-west China) with some populations extending into the southernmost parts of Xinjiang, and into Ladakh in India. Small, isolated populations of wild yak are also found further afield, primarily in western Tibet and eastern Qinghai. In historic times, wild yak were also found in Nepal and Bhutan, but they are now considered extinct in both countries. except as domesticated animals.
The primary habitat of wild yaks consists of treeless uplands between 3,000 and 5,500 m 9,800 and 18,000 ft), dominated by mountains and plateaus. They are most commonly found in alpine meadows with a relatively thick carpet of grasses and sedges, rather than the more barren steppe country. They are herd animals and herds can contain several hundred individuals, although many are much smaller. The herds consist primarily of females and their young with a smaller number of adult males. The remaining males are either solitary, or found in much smaller groups averaging around six individuals. Although they can become aggressive when defending their young, or during the rut, wild yaks generally avoid humans, and may rapidly flee for great distances if approached.