In winter, with ice and snow, it becomes uncomfortable in the Swiss Alps even for the animals. While marmots retreat to hibernate in the protective burrow, ibex, chamois, mountain hares and bearded vultures stay awake even in the cold season. These animals have developed special abilities to withstand the barren and adverse conditions at an altitude of up to 3000 meters. In the Swiss National Park in Graubünden, they remain undisturbed in winter. Park rangers and researchers are the only ones who are allowed to be out and about in the high mountain landscape even in winter.