Wild yak males can be up to 3,250 mm in length and more than 2,000 mm in height. Average weight for male B. grunniens is 1,000 kg with the female being around 300 kg (Nowak, 1999). Domestic yaks can be considerably smaller in weight, with males ranging from 350 to 580 kg and females between 225 to 255 kg (Buchholtz, 1990).
Other physical features of B. grunniens include: a blackish brown pelage, large black upward curving horns, and long hair covering the body including the tail (Nowak, 1999). In contrast, domesticated populations have shorter legs, broader hooves, more varied pelage coloration, and weaker horns which sometimes can be absent altogether (Buchholtz, 1990).
Both wild and domesticated yaks possess large lungs, a high red blood cell count, and higher concentration of hemoglobin than most other bovids. All of these factors allow the yak to live and thrive in higher elevations that would give other, non-acclimated animals elevation sickness (Summers, 1997).
Range mass: 300 to 1000 kg.
Range length: 3250 (high) mm.
Other Physical Features: endothermic ; bilateral symmetry