Yak (Poephagus gruniens) are the cornerstone of life in mountain areas. By providing milk, fibre, meat, transport, fuel, and labour for agriculture and tourism, yak form a foundation on which pastoralists are able to support themselves in these hostile environments. The culture and economy around yak rearing have connected people in adjacent parts of Bhutan, India, and Nepal for centuries. The transboundary movement of herders among the highlands of the three countries is an age-old practice important for the prosperity of herding communities and the vitality of their herds in the Kangchenjunga Landscape.