Ringed seals are born weighing 5. A polar bear may charge a group of walruses, with the goal of separating a young, infirm, or injured walrus from the pod. 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.
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Yet, polar bears will very seldom attack full-grown adult walruses, with the largest male walrus probably invulnerable unless otherwise injured or incapacitated. Since an attack on a walrus tends to be an extremely protracted and exhausting venture, bears have been known to back down from the attack after making the initial injury to the walrus. The whales are of similar size to the walrus and nearly as difficult for the bear to subdue.
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. With the exception of pregnant females, polar bears are active year-round,  although they have a vestigial hibernation induction trigger in their blood.
Unlike brown and black bears, polar bears are capable of fasting for up to several months during late summer and early fall, when they cannot hunt for seals because the sea is unfrozen. Being both curious animals and scavengers,   polar bears investigate and consume garbage where they come into contact with humans. Although seal predation is the primary and an indispensable way of life for most polar bears, when alternatives are present they are quite flexible. Polar bears consume a wide variety of other wild foods, including muskox Ovibos moschatus , reindeer Rangifer tarandus ,  birds, eggs, rodents , crabs , other crustaceans and other polar bears.
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. Given the change in climate, with ice breaking up in areas such as the Hudson Bay earlier than it used to, polar bears are exploiting food resources such as snow geese and eggs, and plants such as lyme grass in increased quantities.
Polar bears have been observed to hunt the small Svalbard reindeer R.
Like the brown bear, most ungulate prey of polar bears is likely to be young, sickly or injured specimens rather than healthy adults. In their southern range, especially near Hudson Bay and James Bay , Canadian polar bears endure all summer without sea ice to hunt from. They still manage to consume some seals, but they are food-deprived in summer as only marine mammal carcasses are an important alternative without sea ice, especially carcasses of the beluga whale. These alternatives may reduce the rate of weight loss of bears when on land.
They were also diving to feed on blue mussels and other underwater food sources like the green sea urchin. Most polar bears elsewhere will never have access to these alternatives, except for the marine mammal carcasses that are important wherever they occur. In Svalbard, polar bears were observed to kill white-beaked dolphins during spring, when the dolphins were trapped in the sea ice. The bears then proceeded to cache the carcasses, which remained and were eaten during the ice-free summer and autumn. Courtship and mating take place on the sea ice in April and May, when polar bears congregate in the best seal hunting areas.
After mating, the fertilized egg remains in a suspended state until August or September. When the ice floes are at their minimum in the fall, ending the possibility of hunting, each pregnant female digs a maternity den consisting of a narrow entrance tunnel leading to one to three chambers. In the den, she enters a dormant state similar to hibernation.
This hibernation-like state does not consist of continuous sleeping; however, the bear's heart rate slows from 46 to 27 beats per minute. Between November and February, cubs are born blind, covered with a light down fur, and weighing less than 0. The earliest recorded birth of polar bears in captivity was on 11 October in the Toronto Zoo.
Female polar bears are noted for both their affection towards their offspring, [ citation needed ] and their valor in protecting them. The Western Hudson Bay subpopulation is unusual in that its female polar bears sometimes wean their cubs at only one and a half years. Females begin to breed at the age of four years in most areas, and five years in the Beaufort Sea area. Polar bears appear to be less affected by infectious diseases and parasites than most terrestrial mammals. Polar bears sometimes have problems with various skin diseases that may be caused by mites or other parasites.
Polar bears rarely live beyond 25 years. Polar bears injured in fights or accidents may either die from their injuries or become unable to hunt effectively, leading to starvation. The polar bear is the apex predator within its range, and is a keystone species for the Arctic. The relationship between ringed seals and polar bears is so close that the abundance of ringed seals in some areas appears to regulate the density of polar bears, while polar bear predation in turn regulates density and reproductive success of ringed seals.
Compared to the Antarctic , where there is no major surface predator, Arctic seals use more breathing holes per individual, appear more restless when hauled out on the ice, and rarely defecate on the ice. Brown bears tend to dominate polar bears in disputes over carcasses,  and dead polar bear cubs have been found in brown bear dens. 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.
This report may well be dubious, however. Researchers tracked 52 sows in the southern Beaufort Sea off Alaska with GPS system collars; no boars were involved in the study due to males' necks being too thick for the GPS-equipped collars. The length of these swims ranged from most of a day to ten days. Ten of the sows had a cub swim with them and after a year, six cubs survived.
The study did not determine if the others lost their cubs before, during, or some time after their long swims. Researchers do not know whether or not this is a new behaviour; before polar ice shrinkage, they opined that there was probably neither the need nor opportunity to swim such long distances. The polar bear may swim underwater for up to three minutes to approach seals on shore or on ice floes.
Polar bears have long provided important raw materials for Arctic peoples, including the Inuit, Yupik , Chukchi , Nenets , Russian Pomors and others. 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. In Russia, polar bear furs were already being commercially traded in the 14th century, though it was of low value compared to Arctic fox or even reindeer fur.
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Estimates of total historical harvest suggest that from the beginning of the 18th century, roughly to animals were being harvested annually in northern Eurasia, reaching a peak of 1, to 1, animals in the early 20th century, and falling off as the numbers began dwindling. 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.
Concerns over the future survival of the species led to the development of national regulations on polar bear hunting, beginning in the mids. The Soviet Union banned all hunting in Canada began imposing hunting quotas in Norway passed a series of increasingly strict regulations from to , and has completely banned hunting since then. In , the International Agreement on the Conservation of Polar Bears was signed by all five nations whose territory is inhabited by polar bears: Member countries agreed to place restrictions on recreational and commercial hunting, ban hunting from aircraft and icebreakers, and conduct further research.
Norway is the only country of the five in which all harvest of polar bears is banned. The agreement was a rare case of international cooperation during the Cold War. Biologist Ian Stirling commented, "For many years, the conservation of polar bears was the only subject in the entire Arctic that nations from both sides of the Iron Curtain could agree upon sufficiently to sign an agreement. Such was the intensity of human fascination with this magnificent predator, the only marine bear. Agreements have been made between countries to co-manage their shared polar bear subpopulations. After several years of negotiations, Russia and the United States signed an agreement in October to jointly set quotas for indigenous subsistence hunting in Alaska and Chukotka.
Although the United States government has proposed that polar bears be transferred to Appendix I of CITES , which would ban all international trade in polar bear parts, polar bears currently remain listed under Appendix II. This status was re-evaluated and confirmed in April , November , and April 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.
More than bears are killed per year by humans across Canada,  a rate calculated by scientists to be unsustainable for some areas, notably Baffin Bay. Government of Nunavut officials announced that the polar bear quota for the Baffin Bay region would be gradually reduced from per year to 65 by the year Because of the way polar bear hunting quotas are managed in Canada, attempts to discourage sport hunting would actually increase the number of bears killed in the short term. Whereas northern communities kill all the polar bears they are permitted to take each year, only half of sport hunters with permits actually manage to kill a polar bear.
If a sport hunter does not kill a polar bear before his or her permit expires, the permit cannot be transferred to another hunter.
In August , Environment Canada published a national polar bear conservation strategy. In Greenland, hunting restrictions were first introduced in and expanded by executive order in However, in it imposed a limit of , while also allowed recreational hunting for the first time. Polar bear were hunted heavily in Svalbard, Norway throughout the 19th century and to as recently as , when the conservation treaty was signed.
Some regulations of hunting did exist. In , poisoning was outlawed while in , certain denning sights were declared off limits. The killing of females and cubs was made illegal in Killing of polar bears decreased somewhat 25—30 years before the treaty. Despite this, the polar bear population continued to decline and by , only around bears were left in Svalbard. Only with the passage of the treaty did they begin to recover. The Soviet Union banned the harvest of polar bears in ; however, poaching continued and is estimated to pose a serious threat to the polar bear population.
Polar bears are currently listed as "Rare", of "Uncertain Status", or "Rehabilitated and rehabilitating" in the Red Data Book of Russia , depending on population. It banned hunting except by indigenous subsistence hunters , banned importing of polar bear parts except polar bear pelts taken legally in Canada , and banned the harassment of polar bears.
Importing products made from polar bears had been prohibited from to under the Marine Mammal Protection Act, and restricted between and Under those restrictions, permits from the United States Fish and Wildlife Service were required to import sport-hunted polar bear trophies taken in hunting expeditions in Canada.
The permit process required that the bear be taken from an area with quotas based on sound management principles. Fish and Wildlife Service published a draft conservation management plan for polar bears to improve their status under the Endangered Species Act and the Marine Mammal Protection Act. Polar bear population sizes and trends are difficult to estimate accurately because they occupy remote home ranges and exist at low population densities.
Polar bear fieldwork can also be hazardous to researchers. According to the World Wildlife Fund , the polar bear is important as an indicator of Arctic ecosystem health. Polar bears are studied to gain understanding of what is happening throughout the Arctic, because at-risk polar bears are often a sign of something wrong with the Arctic marine ecosystem.
The International Union for Conservation of Nature , Arctic Climate Impact Assessment , United States Geological Survey and many leading polar bear biologists have expressed grave concerns about the impact of climate change , including the belief that the current warming trend imperils the survival of the polar bear.
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The key danger posed by 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. In addition to creating nutritional stress, a warming climate is expected to affect various other aspects of polar bear life: Changes in sea ice affect the ability of pregnant females to build suitable maternity dens.
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. 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. This subpopulation feeds heavily on ringed seals in late spring, when newly weaned and easily hunted seal pups are abundant.
Due to warming air temperatures, ice-floe breakup in western Hudson Bay is currently occurring three weeks earlier than it did 30 years ago, reducing the duration of the polar bear feeding season. Geological Survey projects that two-thirds of polar bears will disappear by 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.
A new development is that polar bears have begun ranging to new territory. While not unheard of but still uncommon, polar bears have been sighted increasingly in larger numbers ashore, staying on the mainland for longer periods of time during the summer months, particularly in North Canada, traveling farther inland. Polar bears accumulate high levels of persistent organic pollutants such as polychlorinated biphenyl PCBs and chlorinated pesticides.
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. PCBs have received the most study, and they have been associated with birth defects and immune system deficiency. Many chemicals, such as PCBs and DDT , have been internationally banned due to the recognition of their harm on the environment. Their concentrations in polar bear tissues continued to rise for decades after being banned as these chemicals spread through the food chain.
Since then, the trend seems to have discontinued, with tissue concentrations of PCBs declining between studies performed from to and studies performed from to Oil and gas development in polar bear habitat can affect the bears in a variety of ways. An oil spill in the Arctic would most likely concentrate in the areas where polar bears and their prey are also concentrated, such as sea ice leads.
Disturbance of these sensitive sites may trigger the mother to abandon her den prematurely, or abandon her litter altogether. Steven Amstrup and other U. Geological Survey scientists have predicted two-thirds of the world's polar bears may disappear by , based on moderate projections for the shrinking of summer sea ice caused by climate change,   though the validity of this study has been debated. By , they could disappear from Greenland entirely and from the northern Canadian coast, leaving only dwindling numbers in the interior Arctic Archipelago.
Polar bears diverged from brown bears ,—, years ago and have survived past periods of climate fluctuation. 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. Warnings about the future of the polar bear are often contrasted with the fact that worldwide population estimates have increased over the past 50 years and are relatively stable today.
There are several reasons for the apparent discordance between past and projected population trends: 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. For the indigenous peoples of the Arctic, polar bears have long played an important cultural and material role.
The Inuit and Alaska Natives have many folk tales featuring the bears including legends in which bears are humans when inside their own houses and put on bear hides when going outside, and stories of how the constellation that is said to resemble a great bear surrounded by dogs came into being. Among the Chukchi and Yupik of eastern Siberia , there was a longstanding shamanistic ritual of "thanksgiving" to the hunted polar bear. After killing the animal, its head and skin were removed and cleaned and brought into the home, and a feast was held in the hunting camp in its honor.
To appease the spirit of the bear, traditional song and drum music was played, and the skull was ceremonially fed and offered a pipe.
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The Nenets of north-central Siberia placed particular value on the talismanic power of the prominent canine teeth. 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. It was believed that the "little nephew" the brown bear would not dare to attack a man wearing the tooth of its powerful "big uncle", the polar bear.
Several such sites have been preserved on the Yamal Peninsula. Their distinctive appearance and their association with the Arctic have made polar bears popular icons, especially in those areas where they are native. The Canadian two-dollar coin carries an image of a lone polar bear on its reverse side, while a special millennium edition featured three. Companies such as Coca-Cola ,  Polar Beverages , Nelvana , Bundaberg Rum , and Good Humor-Breyers have used images of the polar bear in advertising, [ citation needed ] while Fox's Glacier Mints have featured a polar bear named Peppy as the brand mascot since Polar bears are popular in fiction, particularly in books for children or teenagers.
From Wikipedia, the free encyclopedia. This article is about the animal. For other uses, see Polar bear disambiguation. Phipps , . Late Pleistocene fossil find in Svalbard: Retrieved 13 December A voyage towards the North Pole undertaken by His Majesty's command, United States Fish and Wildlife service. Retrieved 9 September The polar bear is the largest member of the bear family, with the exception of Alaska's Kodiak brown bears, which equal polar bears in size.
Mammal Species of the World: A Taxonomic and Geographic Reference 3rd ed. Johns Hopkins University Press. University of Michigan Museum of Zoology. Archived from the original on 24 October Retrieved 27 October University of Michigan Press. Summary of polar bear population status. Retrieved 22 December Retrieved July 8, Archived from the original on 15 October Retrieved 21 October Collins Latin Gem Dictionary. The Marine Mammal Center. Archived from the original on 4 June The Inuit name for the polar bear is nanook.
Archived from the original on 4 May Retrieved 20 March Molecular Biology and Evolution. Proceedings of the National Academy of Sciences. The species and the specious". The New York Times. Retrieved 24 July Range-wide status review of the polar bear Ursus maritimus PDF. United States Fish and Wildlife Service. Retrieved 29 December Marine Mammals of the World: Special Publications of the Society for Marine Mammals.
The Society for Marine Mammalogy. Archived from the original on 6 January Their Biology and Management. Retrieved 17 November — via ResearchGate. Integrative and Comparative Biology. Archived from the original on 19 June Retrieved 14 July Who's telling the truth about the fate of a Canadian icon? Archived from the original on 3 May Retrieved 30 December Encyclopedia of Marine Mammals. Journal of Marine Systems.
Archived from the original on 22 April Archived from the original PDF on 5 June Retrieved 22 March The polar bear is the largest member of the bear family, with the exception of Alaska's Kodiak brown bears, a brown bear subspecies, which equal polar bears in size. Encyclopedia of Marine Mammals 2nd ed. The Guinness Book of Animal Records. Measurement and Weight Literature Reports. Retrieved 15 September Archived from the original on 26 February Retrieved 27 February While the algae is harmless to the bears, it is often a worry to the zoos housing them, and affected animals are sometimes washed in a salt solution, or mild peroxide bleach to make the fur white again.
Archived from the original PDF on Canadian Journal of Zoology. Retrieved 21 January Kieran Mulvaney, Discovery News. The Natural History of Canadian Mammals: University of Toronto Press. Archived from the original on 16 June Forecasting the range-wide status of polar bears at selected times in the 21st Century PDF. However, unlike their grizzly ancestors, polar bears are not equipped to survive solely on land. A sow and cub slide on the ice autumn, coastal plain, Arctic National Wildlife Refuge.
Shrewd and ingenious hunters Polar bears use the ice as a platform to track and prey upon seals. Ice isn't optional Descended from grizzlies, polar bears have evolved over , years to thrive on the ice-covered Arctic Ocean. Polar bears are the world's largest land carnivores: Grown male polar bears can weigh up to 1, pounds—as much as a horse or small plane! Polar bear cubs weigh less than two pounds at birth. They weigh about 25 pounds when they leave the den. Polar bears use snow like a towel. First they shake off the water; then they roll in the snow to dry off. A keen sense of smell helps polar bears hunt—they can sniff out seal breathing holes from several miles away.
Polar Bear's Scientific name is Ursus maritimus. Scientists estimate that there are between 20, to 25, polar bears. Polar Bears live an average of 15 to 18 years.