Polar bear in the context of "Bear"

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⭐ Core Definition: Polar bear

The polar bear (Ursus maritimus) is a large bear native to the Arctic and nearby areas. It is closely related to the brown bear, and the two species can interbreed. The polar bear is the largest extant species of bear and land carnivore by body mass, with adult males weighing 300–800 kg (660–1,760 lb). The species is sexually dimorphic, as adult females are much smaller. The polar bear is white- or yellowish-furred with black skin and a thick layer of fat. It is more slender than the brown bear, with a narrower skull, longer neck and lower shoulder hump. Its teeth are sharper and more adapted to cutting meat. The paws are large and allow the bear to walk on ice and paddle in the water.

Polar bears are both terrestrial and pagophilic (ice-living) and are considered marine mammals because of their dependence on marine ecosystems. They prefer the annual sea ice but live on land when the ice melts in the summer. They are mostly carnivorous and specialized for preying on seals, particularly ringed seals. Such prey is typically taken by ambush; the bear may stalk its prey on the ice or in the water, but also will stay at a breathing hole or ice edge to wait for prey to swim by. The bear primarily feeds on the seal's energy-rich blubber. Other prey include walruses, beluga whales and some terrestrial animals. Polar bears are usually solitary but can be found in groups when on land. During the breeding season, male bears guard females and defend them from rivals. Mothers give birth to cubs in maternity dens during the winter. Young stay with their mother for up to two and a half years.

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Polar bear in the context of Arctic

The Arctic (/ˈɑːr(k)tɪk/; from Ancient Greek ἄρκτος (árktos) 'bear') is the polar region of Earth that surrounds the North Pole, lying north of the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway (Nordland, Troms, Finnmark, Svalbard and Jan Mayen), northernmost Sweden (Västerbotten, Norrbotten and Lappland), northern Finland (North Ostrobothnia, Kainuu and Lappi), Russia (Murmansk, Siberia, Nenets Okrug, Novaya Zemlya), the United States (Alaska), Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenland), and northern Iceland (Grímsey and Kolbeinsey), along with the Arctic Ocean and adjacent seas.

Land within the Arctic region has seasonally varying snow and ice cover, with predominantly treeless permafrost under the tundra. Arctic seas contain seasonal sea ice in many places.

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Polar bear in the context of Predator

Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the host) and parasitoidism (which always does, eventually). It is distinct from scavenging on dead prey, though many predators also scavenge; it overlaps with herbivory, as seed predators and destructive frugivores are predators.

Predation behaviour varies significantly depending on the organism. Many predators, especially carnivores, have evolved distinct hunting strategies. Pursuit predation involves the active search for and pursuit of prey, whilst ambush predators instead wait for prey to present an opportunity for capture, and often use stealth or aggressive mimicry. Other predators are opportunistic or omnivorous and only practice predation occasionally.

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Polar bear in the context of History of Greenland

The history of Greenland is a history of life under extreme Arctic conditions: currently, an ice sheet covers about eighty percent of the island, restricting human activity largely to the coasts. The first humans are thought to have arrived in Greenland around 2500 BCE. Their descendants most likely died out and were replaced and succeeded by several other human groups migrating from continental North America since then. There has been no evidence discovered that Greenland was known to Norsemen until the 9th century CE, when Norse Icelandic explorers settled on its southwestern coast. The ancestors of the Greenlandic Inuit who live there today appear to have migrated there later, around the year 1200, across the Nares Strait from northern Canada.

While Inuit survived in the icy world of the Little Ice Age, the early Norse settlements, known as the Eastern Settlement, along the southwestern coast disappeared, leaving Inuit as the only inhabitants of the island for several centuries. During this time, Denmark–Norway, apparently believing the Norse settlements had survived, continued to claim sovereignty over the island despite the lack of any contact between the Norsemen (specifically Icelanders) installed in Greenland and their Scandinavian brethren. In 1721, aspiring to become a colonial power, Denmark-Norway sent a missionary expedition to Greenland with the stated aim of reinstating Christianity among descendants of the Norse Greenlanders who may have converted back to paganism. When the missionaries found no descendants of the Norse Greenlanders, they baptised the Inuit they found living there instead. Denmark-Norway then developed trading colonies along the coast and imposed a trade monopoly and other colonial privileges on the area.

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Polar bear in the context of Marine mammal

Marine mammals are mammals that rely on marine ecosystems for their existence. They include animals such as cetaceans, pinnipeds, sirenians, sea otters and polar bears. They are an informal group, unified only by their reliance on marine environments for feeding and survival.

Marine mammal adaptation to an aquatic lifestyle varies considerably between species. Both cetaceans and sirenians are fully aquatic and therefore are obligate water dwellers. Pinnipeds 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. Sea otters tend to live in kelp forests and estuaries. In contrast, the polar bear is mostly terrestrial and only go into the water on occasions of necessity, and are thus much less adapted to aquatic living. The diets of marine mammals vary considerably as well; some eat zooplankton, others eat fish, squid, shellfish, or seagrass, and a few 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.

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Polar bear in the context of Southern elephant seal

The southern elephant seal (Mirounga leonina) is one of two species of elephant seals. It is the largest member of the clade Pinnipedia and the order Carnivora, as well as the largest extant marine mammal that is not a cetacean. It gets its name from its massive size and the large proboscis of the adult male, which is used to produce very loud roars, especially during the breeding season. A bull southern elephant seal is about 40% heavier than a male northern elephant seal (Mirounga angustirostris), which is nearly twice the weight of a male walrus (Odobenus rosmarus), or 6–7 times heavier than the largest living mostly terrestrial carnivorans, the Kodiak bear and the polar bear.

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Polar bear in the context of Edgeøya

Edgeøya (Norwegian: [ˈɛdʒˌœ͡ʏɑ]), anglicised as Edge Island, is a Norwegian island located in southeast of the Svalbard archipelago; with an area of 5,073 square kilometres (1,960 sq mi), it is the third-largest island in this archipelago. An Arctic island, it forms part of the Søraust-Svalbard Nature Reserve, home to polar bears and reindeer. An ice field covers its eastern side. The island takes its name from Thomas Edge (died 1624), an English merchant and whaler. It is seldom visited today and development of tourist facilities is forbidden by law because of its nature reserve status.

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