Franz Josef Land and snow bunting. Some ivory gulls, little auks and Brünnich's guillemots opt to spend the winter on the islands. The polar bear population of Franz Josef Land lies within the Barents Sea subpopulation, which also includes polar bears inhabiting Svalbard and the western coast of Novaya Zemlya. In 2004, the Barents Sea subpopulation was estimated at 2,650. There is also a population of Arctic fox, which typically have their territories near seabird habitats. Being declared as a marine mammal sanctuary, the island has rich biodiversity of rare marine mammals. Three species of seals habit the archipelago. Harp seal is the
Novaya Zemlya are still used for airfields today. The Soviet Air Force maintained a presence at Rogachevo on the southern part of the southern island, on the westernmost peninsula (). It was used primarily for interceptor aircraft operations, but also provided logistical support for the nearby nuclear test area. Novaya Zemlya was the site of one of the two major nuclear test sites managed by the USSR, used for air drops and underground testing of the largest of Soviet nuclear bombs, in particular the October 30, 1961 air burst explosion of Tsar Bomba, the largest, most powerful nuclear weapon ever detonated. The