wild yak; Bos mutus
Refers specifically to the wild species, Bos mutus, native to the Tibetan Plateau.
Wild yaks inhabit the Tibetan Plateau.
domestic yak; Bos grunniens
Refers to the domesticated form, Bos grunniens, used for milk, meat, and as a pack animal.
Domestic yaks are used for carrying loads.
Yaks are raised on the Tibetan plateau.
Butter is made from yak milk.