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 avalanche that blocked two glacial streams and created a lake in length. Over its history as a nuclear test site, Novaya Zemlya hosted 224 nuclear detonations with a total explosive energy equivalent to 265 megatons of TNT. For comparison, all explosives used in World War II, including the detonations of two US nuclear bombs, amounted to only two megatons. In 1988–1989, "glasnost" helped make the Novaya Zemlya testing activities public knowledge, and in 1990 Greenpeace activists staged a protest at the site. The last nuclear test explosion was in 1990 (also the last for the entire Soviet Union and Russia).