Well adapted for life in cold and harsh conditions, the wild yak is protected from the cold by its thick coat and low number of sweat glands, which help to conserve body heat. It has a large lung capacity and particularly small and numerous red blood cells, enabling it to get the most oxygen possible from the thin, mountain air. Considering its bulk, the wild yak is fairly nimble as it moves around on snowy rocks, grazing on grasses, herbs and lichens, and eating ice and snow as a source of water. It feeds mostly in the morning and evening, and will travel long distances due to the scarcity of the vegetation. With so much protection against cold weather, the wild yak is very sensitive to heat and moves seasonally to avoid higher temperatures. It can withstand strong winds and snowstorms for hours, but may bathe in lakes and streams when the temperature is exceptionally low (4).
Wild yaks tend to gather together, especially the females and young, forming herds of usually 10 to 30 animals, but herds up to 200 are also found. Herds have no fixed members and may join together, or split into smaller herds. Females reach sexual maturity at three to four years, although full size is not reached until six to eight years. Mating takes place in September and single calves are born from April to June, after a gestation of 260 days. The young are weaned before they are one year old, but females will not give birth again for another year. Wild yaks can live for up to 23 years (4).