For six years I lived in a Buddhist monastery where the only female company was a wild yak.
Except where the wild yak is considered as a subspecies of Bos grunniens, there are no recognised subspecies of yak.
The females are about one-third the weight and are about 30% smaller in their linear dimensions when compared to bull wild yaks.
Many wild yaks are killed for food by hunters in China; they are now a vulnerable species.
Small, isolated populations of wild yak are also found farther afield, primarily in western Tibet and eastern Qinghai.
In historic times, wild yaks were also found in Nepal and Bhutan, but they are now considered extinct in both countries, except as domesticated animals.
Although they can become aggressive when defending young, or during the rut, wild yaks generally avoid humans, and may rapidly flee for great distances if any approach.
ARKive - images and movies of the wild yak (Bos grunniens)
There are believed to be fewer than 10,000 mature wild yak in the world.
The Tibetan mastiffs have been guard dogs for thousands of years, known to fight bears, tigers, or wild yak, to attack anything invading their premises.