On the Tibetan plateau, at an altitude of over 4000 meters, space is circumscribed by the distant snowy mountains of Kunlun. The winter temperature drops to -35 ° C and the air contains 35 to 40% less oxygen than at sea level. Every spring, in this extreme environment, the formidable Tibetan antelope undertakes a migration aimed at reproduction. In recent years, the development of the railway line between Beijing and Lhasa cut its route. The survival of the species is at stake since they are less than 75,000 individuals left.