• Wild yak blood contains a lot of fetal hemoglobin, allowing it to carry more oxygen. This feature remains throughout the yak's life.
• Large male wild yaks, especially castrates, carry heavy loads of up to 240 kg easily along steep slopes. Herds trample snow, making it possible to cross passes on horses or yaks with cargo.
• Wild yaks have a thick, matted undercoat that protects them from winter cold. In spring and summer, it sheds in large clumps.
• A dense double coat and special haemoglobin allow life in extreme cold and low oxygen.
• Wild yak horns are long, widely spaced, and curve forward-upward, reaching a length of up to 95 cm. The distance between the ends of the horns is 90 cm.
• The domestic yak crosses with cows, producing hybrids called high nak that are very useful as draft animals. High nak are bred in southern Siberia and Mongolia, are larger in size and have a more docile temperament.
• The wild yak has large lungs and heart adapted to high altitude. It has larger lungs and heart compared to cattle from lowland areas.

Wild yaks stand in height from 1.21 to 1.9 meters and measure in body length from 2.1 to 3.3 meters; their mass ranges from 170.45 kilograms to 0.44 metric tons. The embryonic stage presents with a body mass of from 10 to 25 grams and a body length of from 30 to 60 centimeters. During the newborn stage, the young have a body mass of from 15 to 35 kilograms and a body length of from 80 centimeters to 1.2 meters. The stage of rapid growth results in young yaks with a body mass of from 50 kilograms to 0.25 metric tons and a body length of from 1.2 to 2 meters. Adult yaks possess a body mass of from 0.65 to 1.2 metric tons, and their body length measures from 2.6 to 3.3 meters.