Query: many scientists were surprised when other researchers subsequently found that ringed and bearded seals (the primary prey of polar bears) north of the Bering Strait especially thrived with a longer open-water season, which is particularly conducive to fishing

Relevant passages:
Polar bear <=SEP=> The polar bear ( ursus #Latin maritimus #Latin ) is a carnivorous bear whose native range lies largely within the Arctic Circle , encompassing the Arctic Ocean , its surrounding seas and surrounding land masses . It is a large bear , approximately the same size as the omnivorous Kodiak bear ( Ursus arctos middendorffi ) . A boar ( adult male ) weighs around 350 -- , while a sow ( adult female ) is about half that size . Although it is the sister species of the brown bear , it has evolved to occupy a narrower ecological niche , with many body characteristics adapted for cold temperatures , for moving across snow , ice and open water , and for hunting seals , which make up most of its diet . Although most polar bears are born on land , they spend most of their time on the sea ice . Their scientific name means `` maritime bear '' and derives from this fact . Polar bears hunt their preferred food of seals from the edge of sea ice , often living off fat reserves when no sea ice is present . Because of their dependence on the sea ice , polar bears are classified as marine mammals ; an alternative basis for classification as marine mammals is that they depend on the ocean as their main food source .   Because of expected habitat loss caused by climate change , the polar bear is classified as a vulnerable species , and at least three of the nineteen polar bear subpopulations are currently in decline . For decades , large-scale hunting raised international concern for the future of the species , but populations rebounded after controls and quotas began to take effect . For thousands of years , the polar bear has been a key figure in the material , spiritual , and cultural life of circumpolar peoples , and polar bears remain important in their cultures .

Ringed seal <=SEP=> The ringed seal ( Pusa hispida or Phoca hispida ) , also known as the jar seal and as netsik or nattiq by the Inuit , is an earless seal ( family : Phocidae ) inhabiting the Arctic and sub-Arctic regions . The ringed seal is a relatively small seal , rarely greater than 1.5 m in length , with a distinctive patterning of dark spots surrounded by light grey rings , hence its common name . It is the most abundant and wide-ranging ice seal in the Northern Hemisphere : ranging throughout the Arctic Ocean , into the Bering Sea and Okhotsk Sea as far south as the northern coast of Japan in the Pacific , and throughout the North Atlantic coasts of Greenland and Scandinavia as far south as Newfoundland , and include two freshwater subspecies in northern Europe . Ringed seals are one of the primary prey of polar bears and have long been a component of the diet of indigenous people of the Arctic .

Marine mammal <=SEP=> Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence . They include animals such as seals , whales , manatees , sea otters and polar bears . They do not represent a distinct taxon or systematic grouping , but rather have a polyphyletic relation due to convergent evolution . They are also unified by their reliance on the marine environment for feeding .   Marine mammal adaptation to an aquatic lifestyle vary considerably between species . Both cetaceans and sirenians are fully aquatic and therefore are obligate water dwellers . Seals and sea-lions are semiaquatic ; they spend the majority of their time in the water , but need to return to land for important activities such as mating , breeding and molting . In contrast , both otters and the polar bear are much less adapted to aquatic living . Their diet varies considerably as well ; some may eat zooplankton , others may eat fish , squid , shellfish , sea-grass and a few may eat other mammals . While the number of marine mammals is small compared to those found on land , their roles in various ecosystems are large , especially concerning the maintenance of marine ecosystems , through processes including the regulation of prey populations . This role in maintaining ecosystems makes them of particular concern as 23 % of marine mammal species are currently threatened .   Marine mammals were first hunted by aboriginal peoples for food and other resources . Many were also the target for commercial industry , leading to a sharp decline in all populations of exploited species , such as whales and seals . Commercial hunting lead to the extinction of † Steller 's sea cow and the † Caribbean monk seal . After commercial hunting ended , some species , such as the gray whale and northern elephant seal , have rebounded in numbers ; conversely , other species , such as the North Atlantic right whale , are critically endangered . Other than hunting , marine mammals can be killed as bycatch from fisheries , where they become entangled in fixed netting and drown or starve . Increased ocean traffic causes collisions between fast ocean vessels and large marine mammals . Habitat degradation also threatens marine mammals and their ability to find and catch food . Noise pollution , for example , may adversely affect echolocating mammals , and the ongoing effects of global warming degrade arctic environments .

Bearded seal <=SEP=> The bearded seal ( Erignathus barbatus ) , also called the square flipper seal , is a medium-sized pinniped that is found in and near to the Arctic Ocean . It gets its generic name from two Greek words ( eri and gnathos ) that refer to its heavy jaw . The other part of its Linnaean name means bearded and refers to its most characteristic feature , the conspicuous and very abundant whiskers . When dry , these whiskers curl very elegantly , giving the bearded seal a `` raffish '' look .   Fossils first described in 2002 indicated that , during the Pleistocene epoch , bearded seals ranged as far south as South Carolina .