The dental formula is 220.127.116.11.1.4.3.  One alleged fossil subspecies has been identified: Ursus maritimus tyrannus, which became extinct during the Pleistocene. Due to the absence of human development in its remote habitat, it retains more of its original range than any other extant carnivore. O oso pardo e o oso polar diverxeron dun devanceiro común hai preto de 2 millóns de anos e o cruzamento entre as dúas especies xera descendentes fértiles, feito que pode levar á conclusión de que o oso polar é unha subespecie do oso pardo.  The polar bears that do not den on land make their dens on the sea ice. A boar (adult male) weighs around 350–700 kg (772–1,543 lb), while a sow (adult female) is about half that size. , The polar bear is the most carnivorous member of the bear family, and throughout most of its range, its diet primarily consists of ringed (Pusa hispida) and bearded seals (Erignathus barbatus). History. Ursus polaris Subadults may also be forced to accept a half-eaten carcass if they kill a seal but cannot defend it from larger polar bears.  In recent years, polar bears in the Arctic have undertaken longer than usual swims to find prey, possibly resulting in four recorded drownings in the unusually large ice pack regression of 2005. Ocasionalmente caza bois almiscrados e até mesmo, aínda que raro, outros osos polares.  As of 2015, the International Union for Conservation of Nature (IUCN) reports that the global population of polar bears is 22,000 to 31,000, and the current population trend is unknown. , The effects of climate change are most profound in the southern part of the polar bear's range, and this is indeed where significant degradation of local populations has been observed.  It can kill an adult walrus (Odobenus rosmarus), although this is rarely attempted. Polar bears are stealth hunters, and the victim is often unaware of the bear's presence until the attack is underway. In 1927, poisoning was outlawed while in 1939, certain denning sights were declared off limits. , Being both curious animals and scavengers, polar bears investigate and consume garbage where they come into contact with humans.  The evolutionary pressure of polar bear predation on seals probably accounts for some significant differences between Arctic and Antarctic seals. Polar bears continue to be listed as a species of special concern in Canada because of their sensitivity to overharvest and because of an expected range contraction caused by loss of Arctic sea ice. Since then, the trend seems to have abated, with tissue concentrations of PCBs declining between studies performed from 1989 to 1993 and studies performed from 1996 to 2002.  A male may follow the tracks of a breeding female for 100 km (60 mi) or more, and after finding her engage in intense fighting with other males over mating rights, fights that often result in scars and broken teeth. The 42 teeth of a polar bear reflect its highly carnivorous diet.  The oldest wild bears on record died at age 32, whereas the oldest captive was a female who died in 1991, age 43. , There are several reasons for the apparent discordance between past and projected population trends: estimates from the 1950s and 1960s were based on stories from explorers and hunters rather than on scientific surveys. For example, The Polar Bear Son is adapted from a traditional Inuit tale.  The pair wrestled harmlessly together each afternoon for 10 days in a row for no apparent reason, although the bear may have been trying to demonstrate its friendliness in the hope of sharing the kennel's food. In Russian, it is usually called бе́лый медве́дь (bélyj medvédj, the white bear), though an older word still in use is ошку́й (Oshkúj, which comes from the Komi oski, "bear"). , In the first half of the 20th century, mechanized and overpoweringly efficient methods of hunting and trapping came into use in North America as well. Wikipedia The Free Encyclopedia. Annual ice contains areas of water that appear and disappear throughout the year as the weather changes.  On average, each litter has two cubs. It has been claimed that polar bears will be able to adapt to terrestrial food sources as the sea ice they use to hunt seals disappears. Their concentrations in polar bear tissues continued to rise for decades after being banned, as these chemicals spread through the food chain. Isto débese ao feito de que a sucidade interfire coa capacidade de illamento térmico da pelaxe. Os osos polares cazan a súa comida preferida, as focas, en banquisas, vivindo a miúdo das reservas de graxa cando non hai xeo mariño. When walking, the polar bear tends to have a lumbering gait and maintains an average speed of around 5.6 km/h (3.5 mph). Due to their position at the top of the ecological pyramid, with a diet heavy in blubber in which halocarbons concentrate, their bodies are among the most contaminated of Arctic mammals.  However, due to their lack of prior human interaction, hungry polar bears are extremely unpredictable, fearless towards people and are known to kill and sometimes eat humans. Finalmente, o nome Ursus maritimus pasou a ser utilizado até os nosos días, debido a promoción feita por Harrington (1966), Manning (1971) e Wilson (1976) . " Norwegians used "self-killing guns", comprising a loaded rifle in a baited box that was placed at the level of a bear's head, and which fired when the string attached to the bait was pulled. , The polar bear's most common hunting method is called still-hunting: the bear uses its excellent sense of smell to locate a seal breathing hole, and crouches nearby in silence for a seal to appear. , In Alaska, the effects of sea ice shrinkage have contributed to higher mortality rates in polar bear cubs, and have led to changes in the denning locations of pregnant females. , However, the two species have mated intermittently for all that time, most likely coming into contact with each other during warming periods, when polar bears were driven onto land and brown bears migrated northward. The whales are of similar size to the walrus and nearly as difficult for the bear to subdue. These were traded in the villages of the lower Yenisei and Khatanga rivers to the forest-dwelling peoples further south, who would sew them into their hats as protection against brown bears. Hunters commonly used teams of dogs to distract the bear, allowing the hunter to spear the bear or shoot it with arrows at closer range. Because of their dependence on the sea ice, polar bears are classified as marine mammals. , The Nenets of north-central Siberia placed particular value on the talismanic power of the prominent canine teeth.  A third hunting method is to raid the birth lairs that female seals create in the snow. Italiano 1 652 000+ voci. This behaviour, if it happens, is rare – although the story exists in the oral history of northern peoples and in accounts by early Arctic explorers, there is no record of an eyewitness account of the behaviour in recent decades. O oso de anteollos formou unha póla á parte en torno a 13 millóns de anos atrás. , Females begin to breed at the age of four years in most areas, and five years in the area of the Beaufort Sea. They will even attack adult walruses when their diving holes have frozen over or intercept them before they can get back to the diving hole in the ice. They were also diving to feed on blue mussels and other underwater food sources like the green sea urchin.  Unlike the brown bear, polar bears in captivity are rarely overweight or particularly large, possibly as a reaction to the warm conditions of most zoos.  Fossils show that between 10,000 and 20,000 years ago, the polar bear's molar teeth changed significantly from those of the brown bear. , The white coat usually yellows with age. In their southern range, especially near Hudson Bay and James Bay, Canadian polar bears endure all summer without sea ice to hunt from. , Debate over the listing of the polar bear under endangered species legislation has put conservation groups and Canada's Inuit at opposing positions; the Nunavut government and many northern residents have condemned the U.S. initiative to list the polar bear under the Endangered Species Act.  The bears could disappear from Europe, Asia, and Alaska, and be depleted from the Canadian Arctic Archipelago and areas off the northern Greenland coast.  One bear swam continuously for 9 days in the frigid Bering Sea for 700 km (400 mi) to reach ice far from land.  While they are rare north of 88°, there is evidence that they range all the way across the Arctic, and as far south as James Bay in Canada.  In two areas where harvest levels have been increased based on increased sightings, science-based studies have indicated declining populations, and a third area is considered data-deficient. No verán a pelaxe tórnase amarelada por mor da oxidación producida polo sol. La Fuerza Expedicionaria Americana del Norte de Rusia, también conocida como Expedición Oso Polar, fue un contingente de unos 5.000 miembros del Ejército de los Estados Unidos  que ocuparon Arcángel, en Rusia, como parte de la intervención aliada en la Guerra Civil Rusa, y que combatieron al Ejército Rojo en los alrededores de la región entre septiembre de 1918 y julio de 1919.  Around the Beaufort Sea, however, mature males reportedly average 450 kg (1,000 lb). Polar bears sometimes have problems with various skin diseases that may be caused by mites or other parasites. , Oil and gas development in polar bear habitat can affect the bears in a variety of ways. The family remains in the den until mid-February to mid-April, with the mother maintaining her fast while nursing her cubs on a fat-rich milk.  In September 2015, the polar bear range states agreed upon a "circumpolar action plan" describing their conservation strategy for polar bears. A redución das capas de xeo e o prolongamento do verán están a obrigar os osos polares a buscaren comida en lugares habitados, colocando a especie en conflito co home. Polar bears exposed to oil spill conditions have been observed to lick the oil from their fur, leading to fatal kidney failure. Polar bears injured in fights or accidents may either die from their injuries, or become unable to hunt effectively, leading to starvation.  Although ungulates are not typical prey, the killing of one during the summer months can greatly increase the odds of survival during that lean period.  The growth of the human population in the Eurasian Arctic in the 16th and 17th century, together with the advent of firearms and increasing trade, dramatically increased the harvest of polar bears. Ursus groenlandicus El oso polar es el ursus más carnívoro de todos debido a que en el lugar donde vive casi no crecen plantas, a excepción de algunas semanas del verano. They can be up to 250cm long and 160cm tall and weigh up to 600kg. A pesar de non seren sociais, os osos son capaces, con todo, de compartir os restos dunha balea sen maiores conflitos.  Polar bears gradually moult from May to August, but, unlike other Arctic mammals, they do not shed their coat for a darker shade to provide camouflage in summer conditions. On 15 May 2008, the United States Department of the Interior listed the polar bear as a threatened species under the Endangered Species Act, citing the melting of Arctic sea ice as the primary threat to the polar bear.  Freshwater is limited in these environments because it is either locked up in snow or saline. , Although polar bears are extraordinarily powerful, its primary prey species, the ringed seal, is much smaller than itself, and many of the seals hunted are pups rather than adults. In 1973, the International Agreement on the Conservation of Polar Bears was signed by all five nations whose territory is inhabited by polar bears: Canada, Denmark, Norway, the Soviet Union, and the United States.  The polar bear is among the most sexually dimorphic of mammals, surpassed only by the pinnipeds such as elephant seals.  As the climate change melts sea ice, the U.S. Geological Survey projects that two-thirds of polar bears will disappear by 2050.  Wolves are rarely encountered by polar bears, though there are two records of Arctic wolf (Canis lupus arctos) packs killing polar bear cubs. , This article is about the animal. , With the exception of pregnant females, polar bears are active year-round, although they have a vestigial hibernation induction trigger in their blood. Fifty long-distance swims were recorded; the longest at 354 kilometres (220 mi), with an average of 155 kilometres (96 mi). Like the brown bear, most ungulate prey of polar bears is likely to be young, sickly or injured specimens rather than healthy adults. , Unlike brown bears, polar bears are not territorial. Só o 5% das tentativas ten éxito.  Cubs may hum while nursing.  As the distance increases between the pack ice and the coast, females must swim longer distances to reach favoured denning areas on land. , Many chemicals, such as PCBs and DDT, have been internationally banned due to the recognition of their harm on the environment. They may also eat plants, including berries, roots, and kelp; however, none of these have been a significant part of their diet, except for beachcast marine mammal carcasses. 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. It is the largest extant bear species, as well as the largest extant predatory carnivore.  The dump in Churchill, Manitoba was closed in 2006 to protect bears, and waste is now recycled or transported to Thompson, Manitoba. A. Baker, M. E. Obbard, and B. Malloch, eds.). , The polar bear is the apex predator within its range, and is a keystone species for the Arctic. Historically, the polar bear has also been known as the "white bear". Os pelos nas plantas das patas son duros e proporcionan excelente illamento térmico e tracción sobre a neve. , A widespread legend tells that polar bears cover their black noses with their paws when hunting. Durante miles de anos, o oso polar foi unha figura chave na cultura material e espiritual dos pobos circumpolares, sendo aínda hoxe moi importantes nas súas culturas.  Other provisions included year-round protection of cubs and mothers, restrictions on weapons used and various administrative requirements to catalogue kills. 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.  The proportion of maternity dens on sea ice has changed from 62% between the years 1985 through 1994, to 37% over the years 1998 through 2004. Os territorios, moitas veces enormes, non son defendidos. pp.  However, due to the very small human population around the Arctic, such attacks are rare. Third, the recent effects of climate change have affected sea ice abundance in different areas to varying degrees.  However, the feet are very large to distribute load when walking on snow or thin ice and to provide propulsion when swimming; they may measure 30 cm (12 in) across in an adult. El oso de Banks o grizzly-polar (Ursus arctos x maritimus) es un híbrido raro que se ha producido tanto en cautiverio como en estado salvaje, resultado de cruce de oso pardo y oso polar.En 2006, la aparición de este híbrido en la naturaleza ha sido confirmada por los análisis de ADN de un oso de aspecto extraño que fue encontrado en la isla de Banks al norte de Canadá. Certas actividades humanas como a exploración de gas e petróleo, o turismo, a investigación científica e deportes na neve, perturban o animal no seu ambiente. At up to 2,000 kg (4,400 lb) and a typical adult mass range of 600 to 1,500 kg (1,300 to 3,300 lb), a walrus can be more than twice the bear's weight, has extremely thick skin and has up to 1-metre (3 ft)-long ivory tusks that can be used as formidable weapons.  Some estimates of the global population are around 5,000 to 10,000 in the early 1970s; other estimates were 20,000 to 40,000 during the 1980s. A perda de dentes molares típicos do oso pardo deuse hai 10 ou 20 mil anos.. A maioría dos científicos non recoñecen subespecies de oso polar. tyrannus was significantly larger than the living subspecies. , Steven Amstrup and other U.S. Geological Survey scientists have predicted two-thirds of the world's polar bears may disappear by 2050, based on moderate projections for the shrinking of summer sea ice caused by climate change, though the validity of this study has been debated. In some areas, the polar bear's diet is supplemented by walrus calves and by the carcasses of dead adult walruses or whales, whose blubber is readily devoured even when rotten. Algúns animais migran desta forma do Norte para o Sur seguindo as marxes dos glaciares, mais poden desprazarse tamén por terra firme. This report may well be dubious, however.  Polar bears are thought to have diverged from a population of brown bears that became isolated during a period of glaciation in the Pleistocene from the eastern part of Siberia (from Kamchatka and the Kolym Peninsula). O oso polar é citado polo CITES como de baixo risco de extinción. It is the largest extant bear species, as well as the largest extant predatory carnivore. To appease the spirit of the bear, traditional song and drum music was played, and the skull was ceremonially fed and offered a pipe. Ao nacer o fillote ten 0,6 a 0,7 kg. , Problematic interactions between polar bears and humans, such as foraging by bears in garbage dumps, have historically been more prevalent in years when ice-floe breakup occurred early and local polar bears were relatively thin. , Polar bears were designated "Not at Risk" in April 1986 and uplisted to "Special Concern" in April 1991. , When the polar bear was originally documented, two subspecies were identified: the American polar bear (Ursus maritimus maritimus) by Constantine J. Phipps in 1774, and the Siberian polar bear (Ursus maritimus marinus) by Peter Simon Pallas in 1776. The cheek teeth are smaller and more jagged than in the brown bear, and the canines are larger and sharper.  Vehicle licence plates in the Northwest Territories in Canada are in the shape of a polar bear, as was the case in Nunavut until 2012; these now display polar bear artwork instead. , Polar bears were hunted heavily in Svalbard, Norway throughout the 19th century and to as recently as 1973, when the conservation treaty was signed. O oso polar é un animal de hábitos diúrnos e carácter solitario. Outros nomes xenéricos foron despois propostos, tales como Thalassarctos, Thalarctos e tamén Thalatarctos.  Bacterial leptospirosis and Morbillivirus have been recorded. O oso polar é un nadador e un corredor capaz, o que o torna un cazador eficiente tanto na auga como na terra firme.  Durante décadas, a caza a grande escala supuxo unha preocupación internacional polo futuro da especie, mais as poboacións recuperáronse despois da imposición de controis.  In 2010, the Ministry of Natural Resources and Environment published a strategy for polar bear conservation in Russia. "The influence of climate variability on polar bear (, "Diet composition of polar bears in Svalbard and the western Barents Sea", "Interactions between polar bears and overwintering walruses in the Central Canadian High Arctic", "Polar bear metabolism cannot cope with ice loss", "Comments on 'Carnivorous walrus and some Arctic zoonoses, "Hudson Bay Post — Goodbye Churchil [sic] Dump", "What to eat now? Most brown bears have about 2 percent genetic material from polar bears, but one population, the ABC Islands bears, has between 5 percent and 10 percent polar bear genes, indicating more frequent and recent mating. Atinxen a madurez sexual entre os 5 e 6 anos e en condicións naturais, viven unha media de 15 a 18 anos. Os osos polares reprodúcense entre os meses de marzo e xuño, con implantación diferida dos óvulos fecundados, de modo que o período de xestación se torna moi longo, entre 200 a 265 días, variando de acordo coas condicións ambientais. Polar bear. Polar bears appear to be less affected by infectious diseases and parasites than most terrestrial mammals. In Svalbard, polar bears were observed to kill white-beaked dolphins during spring, when the dolphins were trapped in the sea ice.  Thinner sea ice tends to deform more easily, which appears to make it more difficult for polar bears to access seals. Todas esas adaptacións proporciónanlles unha maior hidrodinámica que facilita a natación. When two polar bears meet, they have a special way of greeting each other. The male's ornamental foreleg hair is thought to attract females, serving a similar function to the lion's mane.  As of 2006, in Alaska, 42% of cubs were reaching 12 months of age, down from 65% in 1991. 1 Taxonomía 2 Características 2.1 Visión 2.2 Olfato 2.3 Patas 3 Esqueleto 4… , When stalking land animals, such as muskox, reindeer, and even willow ptarmigan (Lagopus lagopus), polar bears appear to make use of vegetative cover and wind direction to bring them as close to their prey as possible before attacking.  Son animales de gran tamaño, generalmente omnívoros ya que, a pesar de su temible dentadura, comen frutos, raíces e insectos, además de carne.Sin embargo, el oso polar, debido a la escasez de otras fuentes de alimento, se alimenta casi únicamente de carne (focas).  The numbers taken grew rapidly in the 1960s, peaking around 1968 with a global total of 1,250 bears that year. As femias están aptas para a reprodución unha vez cada tres anos, sendo un dos mamíferos con menor capacidade reprodutiva. Ursus ungavensis  This may cause an increased reliance on terrestrial diets, such as goose eggs, waterfowl and caribou, as well as increased human–bear conflict. Pero esos primeros osos polares no eran como el que conocemos ahora.  Polar bears have also been seen to prey on beluga whales (Delphinapterus leucas) and narwhals (Monodon monoceros), by swiping at them at breathing holes.  In the Norwegian-administered Svalbard archipelago, the polar bear is referred to as Isbjørn ("ice bear"). Aos seis meses de idade, un fillote é capaz de fuxir correndo dun adulto. 1 Appearance 2 Songs 3 Clues 4 Trivia 5 Gallery 6 References Oso Polar is a carefree sea captain who wears a golden robe with black details and a red neckerchief around the neck. A súa taxa de éxito, con todo, é baixa. , Courtship and mating take place on the sea ice in April and May, when polar bears congregate in the best seal hunting areas. This hibernation-like state does not consist of continuous sleeping; however, the bear's heart rate slows from 46 to 27 beats per minute. , The bear family, Ursidae, is thought to have split from other carnivorans about 38 million years ago.  When pregnant, however, females can weigh as much as 500 kg (1,100 lb).  Only once the spirit was appeased was the skull be separated from the skin, taken beyond the bounds of the homestead, and placed in the ground, facing north. , Female polar bears have been known to adopt other cubs. Los osos o úrsidos (Ursidae) son una familia de mamíferos omnívoros. As femias deféndeas mesmo fronte a un macho que mida o duplo do seu tamaño. Photos, facts, videos from Polar Bears International that funds population, preservation, and DNA studies of the polar bear, Map: Here's where the polar bears are vanishing, https://en.wikipedia.org/w/index.php?title=Polar_bear&oldid=990856734, Taxa named by Constantine Phipps, 2nd Baron Mulgrave, Articles with dead external links from December 2016, Articles with permanently dead external links, Wikipedia indefinitely semi-protected pages, Short description is different from Wikidata, All Wikipedia articles written in Canadian English, Articles containing potentially dated statements from 2016, All articles containing potentially dated statements, Articles with unsourced statements from August 2011, Wikipedia articles in need of updating from December 2019, All Wikipedia articles in need of updating, Creative Commons Attribution-ShareAlike License, This page was last edited on 26 November 2020, at 22:14. En 2005, afirmouse ter visto un total de cerca de 40 osos nadando centenares de quilómetros en busca dalgunha capa de xeo flotante á cal puidesen subir. , Because of expected habitat loss caused by climate change, the polar bear is classified as a vulnerable species. Aliméntase tamén de aves, roedores, moluscos, caranguexos, morsas e belugas. , According to the World Wildlife Fund, the polar bear is important as an indicator of Arctic ecosystem health.  Malia que a maioría dos osos polares nacen en terra, pasan a meirande parte da súa vida no mar conxelado.  While most of that quota is hunted by the indigenous Inuit people, a growing share is sold to recreational hunters. The melting sea ice in the Arctic may be causing an increase of orcas in the Arctic sea, which may increase the risk of predation on polar bears but also may benefit the bears by providing more whale carcasses that they can scavenge. " Cubs are especially playful as well. Polar bears rarely live beyond 25 years.  This was the case for 40% of cubs there in the early 1980s; however by the 1990s, fewer than 20% of cubs were weaned this young. O cranio e o pescozo son alongados. Thawing of permafrost would affect the bears who traditionally den underground, and warm winters could result in den roofs collapsing or having reduced insulative value. Para se limparen, usan as patas, a lingua, auga ou neve. , Modern methods of tracking polar bear populations have been implemented only since the mid-1980s, and are expensive to perform consistently over a large area. 日本語 1 239 000+ 記事. Despois de cada comida, dedican uns 15 minutos para eliminar a sucidade. These alternatives may reduce the rate of weight loss of bears when on land. Polar bears were chased from snowmobiles, icebreakers, and airplanes, the latter practice described in a 1965 New York Times editorial as being "about as sporting as machine gunning a cow. The late spring hunting season ends for polar bears when the ice begins to melt and break up, and they fast or eat little during the summer until the sea freezes again. Por riba dos 10 °C, con todo, isto pode levar ao sobrequecemento do animal. Os machos adultos, como noutras especies, poden atacar e matar as crías.  Current estimates put the global population at between 20,000 and 25,000 or 22,000 and 31,000. , There are 19 generally recognized, discrete subpopulations, though polar bears are thought to exist only in low densities in the area of the Arctic Basin.
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