14-15 million yak (Poephagus grunniens, or Bos grunniens) provide the mainstay of life of several million people in the vast plateau (approx. 3 million sq. km) on “the roof of the world” - the provinces of Tibet, Qinghai, Sichuan and Gansu in western China, with the largest populations. Other provinces of China and countries, including Nepal, India, Bhutan, Mongolia (0.5 million yak) and some of the Russian Federation have smaller, but locally important populations. A small herd has existed at Whipsnade Wild Animal Park in England for about half a century and a population of 2-3 thousand has now grown in North America.