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 effect gradient. The sunlight must bend to the Earth's curvature at least 400 km to allow an elevation rise of 5° for sight of the solar disk. The first person to record the phenomenon was Gerrit de Veer, a member of Willem Barentsz's ill-fated third expedition into the north polar region in 1596–1597. Trapped by the ice, the party was forced to stay for the winter in a makeshift lodge on the archipelago of Novaya Zemlya and endure the polar night. On January 24, 1597, De Veer and another crew member claimed to have seen the Sun appear above the horizon,