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 two full weeks prior to its calculated return. They were met with disbelief by the rest of the crew (who accused De Veer of having used the old Julian calendar instead of the Gregorian calendar introduced several years earlier), but on January 27 the Sun was seen by all "in his full roundnesse". For centuries the account was the source of skepticism, until in the 20th century the phenomenon was finally proven to be genuine. Apart from the image of the Sun, the Novaya Zemlya effect can also elevate the image of other objects above the horizon, such as coastlines