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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, with adult males weighing 300–800 kg (660–1,760 lb).
The key danger for polar bears posed by the effects of climate change is malnutrition or starvation due to habitat loss.Polar bears hunt seals from a platform of sea ice. Rising temperatures cause the sea ice to melt earlier in the year, driving the bears to shore before they have built sufficient fat reserves to survive the period of scarce food in the late summer and early fall.
Polar ecology is the relationship between plants and animals in a polar environment. Polar environments are in the Arctic and Antarctic regions. Arctic regions are in the Northern Hemisphere, and it contains land and the islands that surrounds it.
Although polar bears spend most of their time on the ice rather than in the water, polar bears show the beginnings of aquatic adaptation to swimming (high levels of body fat and nostrils that are able to close), diving, and thermoregulation. Distinctly polar bear fossils can be dated to about 100,000 years ago.
[a] The polar bear is considered to be the largest extant species, [42] with adult males weighing 350–700 kg (770–1,540 lb) and measuring 2.4–3 m (7 ft 10 in – 9 ft 10 in) in total length. [43] The smallest species is the sun bear, which ranges 25–65 kg (55–143 lb) in weight and 100–140 cm (39–55 in) in length. [44]
For the most part, the large carnivores are the dominant species in the ecoregion, mainly the polar bear. It is the keystone species for the area due to many of its habits, including its diet and hunting strategies. In addition, the life history of the 22,000 polar bears in the Arctic clearly defines its current existence in the Arctic Cordillera.
Polar bear in Manitoba, Canada. November 2004. Polar seas is a collective term for the Arctic Ocean (about 4-5 percent of Earth's oceans) and the southern part of the Southern Ocean (south of Antarctic Convergence, about 10 percent of Earth's oceans). In the coldest years, sea ice can cover around 13 percent of the Earth's total surface at its ...
Two Polar Bears. The Arctic National Wildlife Refuge is directly connected to Polar Bears. These bears are known for traveling in the region to den and give birth. Nearly 50 of these species migrate along the coast to the refuge in September. These bears extend more than 800 miles (1,300 km) along the coast of Northern Alaska and Canada. Due to ...