Sometimes, they catch birds at sea by attacking them from below the water or chasing them across the water (Stempniewicz 2006 Stempniewicz et al. 2015), Little Auks Alle alle on debris-covered mountain slopes (Stempniewicz 1993), and the seemingly inaccessible colonies of Brünnich’s Guillemot Uria lomvia and Black-legged Kittiwake Rissa tridactyla, located on steep cliffs (Donaldson et al. They penetrate near-shore waterfowl colonies (Rockwell and Gormezano 2009 Iverson et al. Although only a few specialized bears visit such colonies, they often significantly affect bird breeding success (Rockwell and Gormezano 2009 Prop et al. They may also explore landfills near settlements containing offal and the remains of marine mammals hunted by local people (Russell 1975 Lunn and Stirling 1985).ĭuring the bird breeding season, some polar bears visit bird colonies, eating eggs, chicks and adults caught on the nests. Polar bears compelled by the shrinking sea ice extent to stay longer on land, where access to seals is limited, feed opportunistically on whatever resources are available, e.g., dead fish and cetaceans washed ashore, but also numerous terrestrial mammals from rodents to reindeer Rangifer tarandus (Gormezano and Rockwell 2013). 2015) and walruses Odobenus rosmarus resting on beaches (Donaldson et al. When on ice, polar bears also occasionally hunt ice-locked cetaceans (Smith and Sjare 1990 Derocher 2012 Aars et al. Polar bears have a unique ability to digest seal blubber seals therefore supply most of the energy necessary for bears to survive in the cold Arctic (Best 1977).

2002) because of the bearded seal’s large size (4–5 times larger than ringed seal). In Svalbard in summer, the latter is even more important (55% by biomass of food consumed) than the former (63% by numbers) (Derocher et al. Wherever its populations exist, its main prey consists of sea–ice-dependent seal species, particularly ringed seal Pusa hispida, but in many areas also bearded seal Erignathus barbatus. The top predator dependent on sea ice in the Arctic ecosystem, the polar bear Ursus maritimus is classified as a marine mammal (Amstrup 2003). This study adds to earlier papers on how polar bears in Svalbard have increasingly shifted to a more terrestrial diet, and indicates that they may have an enhanced role as an apex predator in the terrestrial ecosystem. This increase in hunting is probably linked to the reduced ice cover, with bears spending more time on land, and a growing reindeer population. Further, we report several other recent instances of bear–reindeer interactions in Svalbard, suggesting that polar bears now hunt reindeer more frequently than they used to. This report is the first description and documentation of the complete course of a polar bear hunt for adult reindeer in Hornsund, SW Spitsbergen, and also of the bear’s hunting behaviour and the reindeer’s response.

Pre-2000 sources state that polar bears do not attack Svalbard reindeer. They constitute an attractive potential prey offering a significant energy return. Svalbard reindeer Rangifer tarandus platyrhynchus are prevalent and their distribution is completely within the range of polar bears. Terrestrial ungulates could be an attractive substitute prey for them. The importance of terrestrial food to polar bears is disputable, and more data are needed. In recent decades, more polar bears have been forced to remain longer on land, so their access to seals is limited. The polar bear Ursus maritimus is one of the species most endangered by the rapidly declining sea–ice cover in the Arctic, which they use as a platform to hunt fatty, high-energy seals.

Are bears nocturnal hunters