The wild yak was the once numerous and widespread on the entire Tibetan plateau north of the Himalayas, in central China, India, Bhutan, and Nepal. The wild yak weighs up to 1000kg; females are 1/3 that size. It stays in high areas with permanent snow during the warmer months of August and September, and spends the rest of the year at lower elevations. Its thick coat and low number of sweat glands are efficient adaptations for conserving heat. The wild yak grazes on grasses, herbs, and lichens. It usually gathers in groups of 10-30 or more, but may occasionally be linked to larger groups of about 100-200.
Wild Yak females conceive first at the age of 3-4 years. Their full size is reached at 6-8 years. Yaks gestation period is approximately 9 months. Most births are expected to occur from April through June. Some domestic yaks give birth to single calves in alternate years, but in areas of poor grazing, they may give birth only once every three years. Yaks become independent after one year. And the life expectancy rate of a yak is 25 years.
The wild yak feeds mostly in the morning and evening. Because of the sparseness of vegetation, the yak must travel long distances to achieve its needed nourishment. Its extremely sensitive to heat and coordinates it seasonal movements with the temperature and food supply. They also bathe in lakes and streams in severe cold. The yaks range has been reduced by half a century, due the hunting by natives and military personnel.