The wild Yak, Bos mutus, in the few remaining herds of Tibet and western China is the second largest
bovine standing 5-7 feet at the shoulder. (The largest is the wild Asian Gaur, both larger than the American or European Bison/Buffalo).
The domesticated Yak, Bos grunniens,
is significantly smaller. Wild Yaks are typically dark brown but domestic Yaks come in a variety of colours.
Both wild and domestic Yaks have dense, long fur and are well adapted for the cold of the Himalayas, Tibetan plateau and Mongolian plains.
Yaks form large herds, mainly of females, calves and juveniles with a few dominant adult males; other adult males are solitary or form small groups.
Domesticated Yaks provide milk, meat, fur and transport.
Uncontrolled hunting has caused the wild yak to become rare.