A large, long-haired relative of cattle (genus Bos, family Bovidae), up to 2 m tall at the shoulder and weighing an average of 650 kg, that is adapted to life at high altitude, with larger lungs and heart than lowland cattle. Domesticated yaks (B. grunniens) are kept for their milk, wool, and meat, and as working and riding animals, and their manure is used as fuel. There are also wild yaks (B. mutus). Yaks occur throughout the Himalayas, the Tibetan Plateau, and parts of Mongolia and Russia.