Polar Bear - Wikipedia, The Free Encyclopedia

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Polar bear
From Wikipedia, the free encyclopedia

The polar bear (Ursus maritimus) 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).[3] A boar (adult male) weighs around
350–700 kg (770–1,540 lb),[4] while a sow (adult female) is about
half that size. Although it is the sister species of the brown bear,[5] 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 the seals which make up
most of its diet.[6] Although most polar bears are born on land, they
spend most of their time at sea. 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.
The polar bear is classified as a vulnerable species, with eight of the
nineteen polar bear subpopulations in decline.[7] 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 Arctic indigenous peoples,
and polar bears remain important in their cultures.

Contents
1 Naming and etymology
2 Taxonomy and evolution
3 Population and distribution
4 Habitat

Polar bear

Polar bear.

Conservation status

Vulnerable (IUCN 3.1)[1]
Scientific classification
Kingdom:

Animalia

Phylum:

Chordata

Class:

Mammalia

Order:

Carnivora

Family:

Ursidae

Genus:

Ursus

Species:

U. maritimus
Binomial name
Ursus maritimus
Phipps, 1774[2]

5 Biology and behavior
5.1 Physical characteristics
5.2 Hunting and diet
6 Dietary flexibility
6.1 Behavior
6.2 Reproduction and lifecycle
6.2.1 Maternity denning and early life
6.2.2 Later life
6.2.3 Life expectancy
6.3 Ecological role
6.4 Long distance swimmer

Polar bear range

Synonyms

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7 Hunting
7.1 Indigenous people
7.2 History of commercial harvest
7.3 Contemporary regulations
7.3.1 Russia
7.3.2 Greenland
7.3.3 Canada
7.3.4 United States

Ursus eogroenlandicus
Ursus groenlandicus
Ursus jenaensis
Ursus labradorensis
Ursus marinus
Ursus polaris
Ursus spitzbergensis
Ursus ungavensis
Thalarctos maritimus

8 Conservation status, efforts and controversies
8.1 Climate change
8.2 Pollution
8.3 Oil and gas development
8.4 Predictions
8.5 Controversy over species protection
9 Protection in the Noth America
9.1 U.S. Marine Mammal Protection Act
9.2 U.S. Endangered Species Act
9.3 Canadian endangered species legislation
10 In culture
10.1 Indigenous folklore
10.2 Symbols and mascots
10.3 Fiction
11 See also
12 Notes
13 References
14 External links

Naming and etymology
Constantine John Phipps was the first to describe the polar bear as a distinct species in 1774. [1] He chose the
scientific name Ursus maritimus, the Latin for 'maritime bear',[8] due to the animal's native habitat. The Inuit
refer to the animal as nanook[9] (transliterated as nanuq in the Inupiat language).[10] The Yupik also refer to
the bear as nanuuk in Siberian Yupik.[11] The bear is umka in the Chukchi language. In Russian, it is usually
called бе́ лый медве́ дь (bélyj medvédj, the white bear), though an older word still in use is ошку́ й (Oshkúj,
which comes from the Komi oski, "bear").[12] In French, the polar bear is referred to as ours blanc ("white
bear") or ours polaire ("polar bear").[13] In the Norwegian-administered Svalbard archipelago, the polar bear
is referred to as Isbjørn ("ice bear").
The polar bear was previously considered to be in its own genus, Thalarctos.[14] However, evidence of
hybrids between polar bears and brown bears, and of the recent evolutionary divergence of the two species,
does not support the establishment of this separate genus, and the accepted scientific name is now therefore
Ursus maritimus, as Phipps originally proposed.[1]
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Taxonomy and evolution
The bear family, Ursidae, is believed to have split off from other
carnivorans about 38 million years ago.[15] The Ursinae subfamily
originated approximately 4.2 million years ago. [16] The oldest known
polar bear fossil is a 130,000 to 110,000-year-old jaw bone, found on
Prince Charles Foreland in 2004.[17] Fossils show that between ten to
twenty thousand years ago, the polar bear's molar teeth changed
significantly from those of the brown bear.[18] Polar bears are thought
to have diverged from a population of brown bears that became
isolated during a period of glaciation in the Pleistocene[19] or from
the eastern part of Siberia, (from Kamchatka and the Kolym
Peninsula).[20]

Polar bears have evolved adaptations
for Arctic life, for example, large
furry feet and short, sharp, stocky
claws give them good traction on ice.

The evidence from DNA analysis is more complex. The
mitochondrial DNA (mtDNA) of the polar bear diverged from the
brown bear, Ursus arctos, roughly 150,000 years ago.[17] Further, some clades of brown bear, as assessed by
their mtDNA, are more closely related to polar bears than to other brown bears, [21] meaning that the polar
bear would not be a true species according to some species concepts.[22] The mtDNA of Irish brown bears is
particularly close to polar bears.[23] A comparison of the nuclear genome of polar bears with that of brown
bears revealed a different pattern, the two forming genetically distinct clades that diverged approximately
603,000 years ago,[24] although the latest research is based on analysis of the complete genomes (rather than
just the mitochondria or partial nuclear genomes) of polar, brown and black bears, and establishes the
divergence of polar and brown bears at 4–5 million years ago. [25]
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. Most brown bears have about 2 percent genetic material from polar bears, but one population
residing in the Alexander Archipelago has between 5 percent and 10 percent polar bear genes, indicating
more frequent and recent mating.[26] Polar bears can breed with brown bears to produce fertile grizzly–polar
bear hybrids,[19][27] rather than indicating that they have only recently diverged, the new evidence suggests
more frequent mating has continued over a longer period of time, and thus the two bears remain genetically
similar.[26] However, because neither species can survive long in the other's ecological niche, and because
they have different morphology, metabolism, social and feeding behaviors, and other phenotypic
characteristics, the two bears are generally classified as separate species. [28]
When the polar bear was originally documented, two subspecies were identified: Ursus maritimus maritimus
by Constantine J. Phipps in 1774, and Ursus maritimus marinus by Peter Simon Pallas in 1776.[29] This
distinction has since been invalidated. One fossil subspecies has been identified. Ursus maritimus
tyrannus — descended from Ursus arctos — became extinct during the Pleistocene. U.m. tyrannus was
significantly larger than the living subspecies. [19]

Population and distribution
The polar bear is found in the Arctic Circle and adjacent land masses as far south as Newfoundland Island.
Due to the absence of human development in its remote habitat, it retains more of its original range than any
other extant carnivore.[30] 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. Their southernmost range is near the boundary
between the subarctic and humid continental climate zones. They can occasionally drift widely with the sea
ice, and there have been anecdotal sightings as far south as Berlevåg on the Norwegian mainland and the

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Kuril Islands in the Sea of Okhotsk. It is difficult to estimate a global
population of polar bears as much of the range has been poorly
studied; however, biologists use a working estimate of about 20,000
to 25,000 polar bears worldwide.[1][31]

Polar bears investigate the submarine
USS Honolulu 450 kilometres
(280 mi) from the North Pole.

There are 19 generally recognized, discrete subpopulations. [31][32]
The subpopulations display seasonal fidelity to particular areas, but
DNA studies show that they are not reproductively isolated. [33] The
thirteen North American subpopulations range from the Beaufort Sea
south to Hudson Bay and east to Baffin Bay in western Greenland and
account for about 70% of the global population. The Eurasian
population is broken up into the eastern Greenland, Barents Sea, Kara
Sea, Laptev Sea, and Chukchi Sea subpopulations, though there is
considerable uncertainty about the structure of these populations due

to limited mark and recapture data.
The range includes the territory of five nations: Denmark
(Greenland), Norway (Svalbard), Russia, the United States (Alaska)
and Canada. These five nations are the signatories of the International
Agreement on the Conservation of Polar Bears, which mandates
cooperation on research and conservations efforts throughout the
polar bear's range.
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.[34] The most accurate counts require
Polar bears play-fighting
flying a helicopter in the Arctic climate to find polar bears, shooting a
tranquilizer dart at the bear to sedate it, and then tagging the bear. [34]
In Nunavut, some Inuit have reported increases in bear sightings around human settlements in recent years,
leading to a belief that populations are increasing. Scientists have responded by noting that hungry bears may
be congregating around human settlements, leading to the illusion that populations are higher than they
actually are.[34] The Polar Bear Specialist Group of the IUCN takes the position that "estimates of
subpopulation size or sustainable harvest levels should not be made solely on the basis of traditional
ecological knowledge without supporting scientific studies." [35]
Of the 19 recognized polar bear subpopulations, eight are declining, three are stable, one is increasing, and
seven have insufficient data, as of 2009.[7][31]

Habitat
The polar bear is a marine mammal because it spends many months
of the year at sea.[36] However, it is the only living "marine mammal"
with powerful, large limbs and feet that allow them to cover miles on
foot and run on land.[37] Its preferred habitat is the annual sea ice
covering the waters over the continental shelf and the Arctic interisland archipelagos. These areas, known as the "Arctic ring of life",
have high biological productivity in comparison to the deep waters of
the high Arctic.[30][38] The polar bear tends to frequent areas where
sea ice meets water, such as polynyas and leads (temporary stretches
Polar bear jumping on fast ice
of open water in Arctic ice), to hunt the seals that make up most of its
diet.[39] Polar bears are therefore found primarily along the perimeter
of the polar ice pack, rather than in the Polar Basin close to the North Pole where the density of seals is
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low.[40]
Annual ice contains areas of water that appear and disappear throughout the year as the weather changes.
Seals migrate in response to these changes, and polar bears must follow their prey. [38] In Hudson Bay, James
Bay, and some other areas, the ice melts completely each summer (an event often referred to as "ice-floe
breakup"), forcing polar bears to go onto land and wait through the months until the next freeze-up. [38] In the
Chukchi and Beaufort seas, polar bears retreat each summer to the ice further north that remains frozen
year-round.

Biology and behavior
Physical characteristics
The only other bear of a similar size to the polar bear is the Kodiak bear,
which is a subspecies of brown bear.[41] Adult male polar bears weigh
350–700 kg (770–1,540 lb) and measure 2.4–3 metres (7 ft 10 in–9 ft 10 in)
in total length.[42] The Guinness Book of World Records listed the average
male as having a body mass of 385 to 410 kg (849 to 904 lb) and a shoulder
height of 133 cm (4 ft 4 in), slightly smaller than the average cited for male
Kodiak bears.[43] Around the Beaufort Sea, however, mature males
reportedly average 450 kg (1,000 lb).[44] Adult females are roughly half the
size of males and normally weigh 150–250 kg (330–550 lb), measuring
1.8–2.4 metres (5 ft 11 in–7 ft 10 in) in length. Elsewhere, a slightly larger
estimated average weight of 260 kg (570 lb) was claimed for adult
females.[45] When pregnant, however, females can weigh as much as 500 kg
(1,100 lb).[42] The polar bear is among the most sexually dimorphic of
mammals, surpassed only by the pinnipeds such as elephant seals.[46] The
largest polar bear on record, reportedly weighing 1,002 kg (2,209 lb),
was a male shot at Kotzebue Sound in northwestern Alaska in
1960.[43] This specimen, when mounted, stood 3.39 m (11 ft 1 in) tall
on its hindlegs.[43] The shoulder height of an adult polar bear is 122
to 160 cm (4 ft 0 in to 5 ft 3 in).[43][47] While all bears are shorttailed, the polar bear's tail is relatively the shortest amongst living
bears, ranging from 7 to 13 cm (2.8 to 5.1 in) in length.[48]

Skull, as illustrated by N. N.
Kondakov

Polar bear skeleton
Compared with its closest relative, the brown bear, the polar bear has
a more elongated body build and a longer skull and nose.[28] As
predicted by Allen's rule for a northerly animal, the legs are stocky
and the ears and tail are small. [28] 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.[49] The pads of the paws are covered with small, soft
papillae (dermal bumps) which provide traction on the ice. [28] The
polar bear's claws are short and stocky compared to those of the
Captive polar bear swimming
brown bear, perhaps to serve the former's need to grip heavy prey and
ice.[28] The claws are deeply scooped on the underside to assist in
digging in the ice of the natural habitat. Research of injury patterns in polar bear forelimbs found injuries to
the right forelimb to be more frequent than those to the left, suggesting, perhaps, right-handedness. [50]
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.

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The 42 teeth of a polar bear reflect its highly carnivorous diet. [28] The cheek teeth are smaller and more
[28]
jagged than in the brown bear, and the canines are larger and sharper.[28] The dental formula is 3.1.4.2
3.1.4.3
Polar bears are superbly insulated by up to 10 cm (4 in) of blubber,[49] their hide and their fur; they overheat
at temperatures above 10 °C (50 °F), and are nearly invisible under infrared photography.[51] Polar bear fur
consists of a layer of dense underfur and an outer layer of guard hairs, which appear white to tan but are
actually transparent.[49] The guard hair is 5–15 cm (2–6 in) over most of the body.[52] Polar bears gradually
moult from May to August,[53] but, unlike other Arctic mammals, they do not shed their coat for a darker
shade to camouflage themselves in the summer conditions. The hollow guard hairs of a polar bear coat were
once thought to act as fiber-optic tubes to conduct light to its black skin, where it could be absorbed;
however, this theory was disproven by recent studies. [54]
The white coat usually yellows with age. When kept in captivity in warm, humid conditions, the fur may turn
a pale shade of green due to algae growing inside the guard hairs.[55] Males have significantly longer hairs
on their forelegs, which increase in length until the bear reaches 14 years of age. The male's ornamental
foreleg hair is thought to attract females, serving a similar function to the lion's mane. [56]
The polar bear has an extremely well developed sense of smell, being able to detect seals nearly 1.6 km
(1 mi) away and buried under 1 m (3 ft) of snow.[57] Its hearing is about as acute as that of a human, and its
vision is also good at long distances.[57]
The polar bear is an excellent swimmer and often will swim for days.[58] One bear swam continuously for 9
days in the frigid Bering Sea for 400 mi (687 km) to reach ice far from land. She then traveled another
1,100 mi (1,800 km) [59] With its body fat providing buoyancy, the bear swims in a dog paddle fashion using
its large forepaws for propulsion.[60] Polar bears can swim 10 km/h (6 mph). 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). [60] When
sprinting, they can reach up to 40 km/h (25 mph).[61]

Hunting and diet
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).[63] The
Arctic is home to millions of seals, which become prey when they
surface in holes in the ice in order to breathe, or when they haul out
on the ice to rest.[62][64] Polar bears hunt primarily at the interface
between ice, water, and air; they only rarely catch seals on land or in
open water.[65]
The long muzzle and neck of the

The polar bear's most common hunting method is called stillpolar bear help it to search in deep
hunting:[66] The bear uses its excellent sense of smell to locate a seal
holes for seals, while powerful
breathing hole, and crouches nearby in silence for a seal to appear.
hindquarters enable it to drag massive
The bear may lay in wait for several hours. When the seal exhales, the
prey.[62]
bear smells its breath, reaches into the hole with a forepaw, and drags
it out onto the ice. The polar bear kills the seal by biting its head to
crush its skull. The polar bear also hunts by stalking seals resting on the ice: Upon spotting a seal, it walks to
within 90 m (100 yd), and then crouches. If the seal does not notice, the bear creeps to within 9 to 12 m (30
to 40 ft) of the seal and then suddenly rushes forth to attack. [62] A third hunting method is to raid the birth
lairs that female seals create in the snow. [66]
A widespread legend tells that polar bears cover their black noses with their paws when hunting. This
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behavior, if it happens, is rare – although the story exists in native oral history and in accounts by early
Arctic explorers, there is no record of an eyewitness account of the behavior in recent decades. [60]
Mature bears tend to eat only the calorie-rich skin and blubber of the seal,
which are highly digestible,[67] whereas younger bears consume the
protein-rich red meat.[62] Studies have also photographed polar bears scaling
near-vertical cliffs, to eat birds' chicks and eggs. [68][69][70] For subadult bears
which are independent of their mother but have not yet gained enough
experience and body size to successfully hunt seals, scavenging the carcasses
from other bears' kills is an important source of nutrition. Subadults may also
be forced to accept a half-eaten carcass if they kill a seal but cannot defend it
from larger polar bears. After feeding, polar bears wash themselves with
water or snow.[60]
Polar bear at a whale carcass

The polar bear is perhaps unequaled by any other living land predator in its
enormous physical power. However, its primary prey species, the ringed seal,
is much smaller than itself, and many of the seals hunted are pups rather than adults. Ringed seals are born
weighing 5.4 kg (12 lb) and grown to an estimated average weight of only 60 kg (130 lb). [71][72] They also in
places prey heavily upon the harp seal (Pusa groenlandica) or the harbor seal.[73] The bearded seal, on the
other hand, can be nearly the same size as the bear itself, averaging 270 kg (600 lb). [72] Adult male bearded
seals, at 350 to 500 kg (770 to 1,100 lb) are believed to be too large for a female bear to overtake, [74] and so
are potential prey only for mature male bears. [75] Enormously powerful large males also occasionally attempt
to hunt and kill even larger prey items.[76] It can kill an adult walrus (Odobenus rosmarus),[73][77] although
this is rarely attempted. 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, [78] and has up to 1-metre (3 ft)-long ivory
tusks that can be used as formidable weapons. 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. 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.[79] Polar bears have also been seen to prey on beluga whales (Delphinapterus
leucas)[73] and narwhals (Monodon monoceros),[73] by swiping at them at breathing holes. The whales are of
similar size to the walrus and nearly as difficult for the bear to subdue. [80][81] Most terrestrial animals in the
Arctic can outrun the polar bear on land as polar bears overheat quickly, and most marine animals the bear
encounters can outswim it. 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. [82] Polar
bears sometimes like to go fishing where they swim underwater to catch fish like the arctic charr or the
Fourhorn sculpin.[64]
With the exception of pregnant females, polar bears are active year-round, [83] 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.[83] When sea ice is unavailable during summer and early autumn, some populations live off fat
reserves for months at a time.[51] Being both curious animals and scavengers, [78][84] polar bears investigate
and consume garbage where they come into contact with humans.[73][78] Polar bears may attempt to consume
almost anything they can find, including hazardous substances such as styrofoam, plastic, car batteries,
ethylene glycol, hydraulic fluid, and motor oil.[78][84] The dump in Churchill, Manitoba was closed in 2006
to protect bears, and waste is now recycled or transported to Thompson, Manitoba.[85][86]

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Dietary flexibility
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 will consume a wide variety of other wild foods,
including muskox (Ovibos moschatus), reindeer (Rangifer
tarandus),.[87] birds, eggs, rodents, crabs, other crustaceans and other
polar bears. They may also eat plants,. [87] including berries, roots,
and kelp,[87] however none of these are a significant part of their
diet,[78] except that beachcast marine mammal carcasses are an
exception.[88] When stalking land animals, such as muskox,
reindeer.[87] 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. Polar
bears have been observed to hunt the small Svalbard reindeer (R. t.
Some characteristic postures:
platyrhynchus), which weigh only 40 to 60 kg (90 to 130 lb) as
1. – at rest;
adults, as well as the Barren-ground caribou (R. t. groenlandicus),
2. – at an estimated reaction;
[89][90][91]
which is about twice as heavy as that.
Adult muskox, which
3. – when feeding
can weigh 450 kg (1,000 lb) or more, are a more formidable
quarry.[92] 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. Like the brown
bear, most ungulate prey of polar bears is likely to be young, sickly or injured specimens rather than healthy
adults.[90] The polar bear's biology is specialized to require large amounts of fat from marine mammals, and
it cannot derive sufficient caloric intake from terrestrial food. [93][94]
In their southern range, especially near Hudson Bay and James Bay Canada polar bears live all summer
without sea ice.[87] Here their food ecology shows their dietary flexibility. 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,[95] especially carcasses of the bowhead whale.[96] These alternatives may reduce
the rate of weight loss of bears when on land.[97] One scientist found that 71% of the Hudson Bay bears had
fed on seaweed (marine algae) and that about half were feeding on birds [73] like sea ducks, especially the
oldsquaw (53%), common eider, long-tailed duck or dovekieby swimming underwater to catch them. They
were also diving to feed on blue mussels and other underwater food sources like the green sea urchin. 24%
had eaten moss recently, 19% had consumed grass, 34% had eaten black crowberry and about half had
consumed willows.[87] This study illustrates the polar bear's dietary flexibility but it does not represent its life
history elsewhere. Most polar bears elsewhere will never have access to these alternatives, except for the
marine mammal carcasses that are important wherever they occur.

Behavior
Unlike grizzly bears, polar bears are not territorial. Although stereotyped as being voraciously aggressive,
they are normally cautious in confrontations, and often choose to escape rather than fight. [98] Satiated polar
bears rarely attack humans unless severely provoked. 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.[82] Many attacks by brown bears are the result of surprising the animal, which is not the case
with the polar bear. Polar bears are stealth hunters, and the victim is often unaware of the bear's presence
until the attack is underway.[99] Whereas brown bears often maul a person and then leave, polar bear attacks
are more likely to be predatory and are almost always fatal. [99] However, due to the very small human
population around the Arctic, such attacks are rare. Michio Hoshino, a Japanese wildlife photographer, was
once pursued briefly by a hungry male polar bear in northern Alaska. According to Hoshino, the bear started

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running but Hoshino made it to his truck. The bear was able to reach
the truck and tore one of the doors off the truck before Hoshino was
able to drive off.[100]
In general, adult polar bears live solitary lives. Yet, they have often
been seen playing together for hours at a time and even sleeping in an
embrace,[82] and polar bear zoologist Nikita Ovsianikov has
described adult males as having "well-developed friendships." [98]
Cubs are especially playful as well. Among young males in particular,
play-fighting may be a means of practicing for serious competition
during mating seasons later in life.[101] Polar bears have a wide range
of vocalisations, including bellows, roars, growls, chuffs and
purrs.[102]

Polar bear males frequently
play-fight. During the mating season,
actual fighting is intense and often
leaves scars or broken teeth.

In 1992, a photographer near Churchill took a now widely circulated
set of photographs of a polar bear playing with a Canadian Eskimo
Dog (Canis lupus familiaris) a tenth of its size.[103][104] The pair wrestled harmlessly together each afternoon
for ten 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. [103] This kind of social interaction is uncommon; it is
far more typical for polar bears to behave aggressively towards dogs. [103]

Reproduction and lifecycle
Courtship and mating take place on the sea ice in April and May,
when polar bears congregate in the best seal hunting areas. [105] 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 which often result in scars and
broken teeth.[105] Polar bears have a generally polygynous mating
system; recent genetic testing of mothers and cubs, however, has
uncovered cases of litters in which cubs have different fathers. [106]
Partners stay together and mate repeatedly for an entire week; the
mating ritual induces ovulation in the female.[107]

Cubs are born helpless and typically
nurse for two and a half years

After mating, the fertilized egg remains in a suspended state until August or September. During these four
months, the pregnant female eats prodigious amounts of food, gaining at least 200 kg (440 lb) and often
more than doubling her body weight.[105]
Maternity denning and early life
When the ice floes break up 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.[105] Most maternity dens are in
snowdrifts, but may also be made underground in permafrost if it is not
sufficiently cold yet for snow.[105] In most subpopulations, maternity dens
are situated on land a few kilometers from the coast, and the individuals in a
subpopulation tend to reuse the same denning areas each year. [30] The polar
Female emerging from her
bears that do not den on land make their dens on the sea ice. In the den, she
maternity den
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.[108] Her body temperature does not decrease during this period as it would for a

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typical mammal in hibernation.[51][109]
Between November and February, cubs are born blind, covered with a light down fur, and weighing less than
0.9 kg (2.0 lb),[107] but in captivity they might be delivered in the earlier months. The earliest recorded birth
of polar bears in captivity was on 11 October 2011 in the Toronto Zoo.[110] On average, each litter has two
cubs.[105] 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. [105] By the time the mother breaks open the entrance to the
den, her cubs weigh about 10 to 15 kilograms (22 to 33 lb). [105] For about 12 to 15 days, the family spends
time outside the den while remaining in its vicinity, the mother grazing on vegetation while the cubs become
used to walking and playing.[105] Then they begin the long walk from the denning area to the sea ice, where
the mother can once again catch seals. [105] Depending on the timing of ice-floe breakup in the fall, she may
have fasted for up to eight months.[105]
Cubs may fall prey to wolvesor to starvation. Female polar bears are
noted for both their affection towards their offspring, and their
valiance in protecting them. One case of adoption of a wild cub has
been confirmed by genetic testing.[106] Adult male bears occasionally
kill and eat polar bear cubs,[111] for reasons that are unclear.[112] As
of 2006, in Alaska, 42% of cubs now reach 12 months of age, down
from 65% 15 years ago.[113] In most areas, cubs are weaned at two
and a half years of age,[105] when the mother chases them away or
abandons them. The western coast of Hudson Bay is unusual in that
Cub nursing
its female polar bears sometimes wean their cubs at only one and a
half years.[105] 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. [114] After the mother leaves,
sibling cubs sometimes travel and share food together for weeks or months. [82]
Later life
Females begin to breed at the age of four years in most areas, and five years in the Beaufort Sea area. [105]
Males usually reach sexual maturity at six years; however, as competition for females is fierce, many do not
breed until the age of eight or ten.[105] A study in Hudson Bay indicated that both the reproductive success
and the maternal weight of females peaked in their mid-teens. [115]
Polar bears appear to be less affected by infectious diseases and parasites than most terrestrial mammals. [112]
Polar bears are especially susceptible to Trichinella, a parasitic roundworm they contract through
cannibalism,[116] although infections are usually not fatal. [112] Only one case of a polar bear with rabies has
been documented, even though polar bears frequently interact with Arctic foxes, which often carry
rabies.[112] Bacterial Leptospirosis and Morbillivirus have been recorded. Polar bears sometimes have
problems with various skin diseases which may be caused by mites or other parasites.
Life expectancy
Polar bears rarely live beyond 25 years.[117] The oldest wild bears on record died at age 32, whereas the
oldest captive was a female who died in 1991, age 43. [118] The causes of death in wild adult polar bears are
poorly understood, as carcasses are rarely found in the species's frigid habitat. [112] In the wild, old polar
bears eventually become too weak to catch food, and gradually starve to death. Polar bears injured in fights
or accidents may either die from their injuries or become unable to hunt effectively, leading to starvation. [112]

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Ecological role
The polar bear is the apex predator within its range. Several animal species, particularly Arctic Foxes (Vulpes
lagopus) and Glaucous Gulls (Larus hyperboreus), routinely scavenge polar bear kills. [60]
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.[65] The evolutionary pressure of polar bear predation on seals probably
accounts for some significant differences between Arctic and Antarctic 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. [60] The baby fur of most Arctic seal
species is white, presumably to provide camouflage from predators, whereas Antarctic seals all have dark fur
at birth.[60]
Polar bears rarely enter conflict with other predators, though recent brown bear encroachments into polar
bear territories have led to antagonistic encounters. Brown bears tend to dominate polar bears in disputes
over carcasses,[119] and dead polar bear cubs have been found in brown bear dens. [120] Wolves are rarely
encountered by polar bears, though there are two records of Arctic wolf (Canis lupus arctos) packs killing
polar bear cubs.[121] A rather unlikely killer of a grown polar bear has reportedly included a wolverine (Gulo
gulo), anecedotely reported to have suffocated a bear with a bite to the throat during a conflict over food. [122]
Polar bears are sometimes the host of arctic mites such as Alaskozetes antarcticus.[60]

Long distance swimmer
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. Fifty long-distance
swims were recorded; the longest at 354 kilometres (220 mi), with an average of 155 kilometres (96 mi). 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 behavior; before
polar ice shrinkage, they opined that there was probably neither the need nor opportunity to swim such long
distances.[123]

Hunting
Indigenous people
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.[124] Almost all parts of captured animals had a use. [125]
The fur was used in particular to sew trousers and, by the Nenets, to
make galoshes-like outer footwear called tobok; the meat is edible,
despite some risk of trichinosis; the fat was used in food and as a fuel
for lighting homes, alongside seal and whale blubber; sinews were
Skins of hunted polar bears
used as thread for sewing clothes; the gallbladder and sometimes
heart were dried and powdered for medicinal purposes; the large
canine teeth were highly valued as talismans.[126] Only the liver was not used, as its high concentration of
vitamin A is poisonous.[127] Hunters make sure to either toss the liver into the sea or bury it in order to spare
their dogs from potential poisoning.[126] Traditional subsistence hunting was on a small enough scale to not
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significantly affect polar bear populations, mostly because of the sparseness of the human population in polar
bear habitat.[128]

History of commercial harvest
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. [126] 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.[51][129] However, since polar bear fur has always played a marginal
commercial role, data on the historical harvest is fragmentary. It is known, for example, that already in the
winter of 1784/1785 Russian Pomors on Spitsbergen harvested 150 polar bears in Magdalenefjorden.[126] In
the early 20th century, Norwegian hunters were harvesting 300 bears a year at the same location. Estimates
of total historical harvest suggest that from the beginning of the 18th century, roughly 400 to 500 animals
were being harvested annually in northern Eurasia, reaching a peak of 1,300 to 1,500 animals in the early
20th century, and falling off as the numbers began dwindling. [126]
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. [130] 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."[130] The numbers taken grew rapidly in the 1960s, peaking around 1968
with a global total of 1,250 bears that year.[131]

Contemporary regulations
Concerns over the future survival of the species led to the
development of national regulations on polar bear hunting, beginning
in the mid-1950s. The Soviet Union banned all hunting in 1956.
Canada began imposing hunting quotas in 1968. Norway passed a
series of increasingly strict regulations from 1965 to 1973, and has
completely banned hunting since then. The United States began
regulating hunting in 1971 and adopted the Marine Mammal
Protection Act in 1972. In 1973, the International Agreement on the
Conservation of Polar Bears was signed by all five nations whose
Road sign warning about the presence
territory is inhabited by polar bears: Canada, Denmark, Norway, the
of polar bears
Soviet Union, and the United States. Member countries agreed to
place restrictions on recreational and commercial hunting, ban
hunting from aircraft and icebreakers, and conduct further research. [132] The treaty allows hunting "by local
people using traditional methods". 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." [133]
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 2000 to jointly
set quotas for indigenous subsistence hunting in Alaska and Chukotka.[134] The treaty was ratified in October
2007.[135]
Russia
The Soviet Union banned the harvest of polar bears in 1956, however poaching continued and is believed to

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pose a serious threat to the polar bear population.[32] In recent years, polar bears have approached coastal
villages in Chukotka more frequently due to the shrinking of the sea ice, endangering humans and raising
concerns that illegal hunting would become even more prevalent. [136] In 2007, the Russian government made
subsistence hunting legal for Chukotka natives only, a move supported by Russia's most prominent bear
researchers and the World Wide Fund for Nature as a means to curb poaching.[136]
Greenland
In Greenland, hunting restrictions were first introduced in 1994 and expanded by executive order in 2005. [32]
Until 2005 Greenland placed no limit on hunting by indigenous people. However, in 2006 it imposed a limit
of 150, while also allowed recreational hunting for the first time. [137] Other provisions included year-round
protection of cubs and mothers, restrictions on weapons used, and various administrative requirements to
catalogue kills.[32]
Canada
About 500 bears are killed per year by humans across Canada, [138] a
rate believed by scientists to be unsustainable for some areas, notably
Baffin Bay.[31] Canada has allowed sport hunters accompanied by
local guides and dog-sled teams since 1970,[139] but the practice was
not common until the 1980s.[140] The guiding of sport hunters
provides meaningful employment and an important source of income
for native communities in which economic opportunities are few. [34]
Sport hunting can bring CDN$20,000 to $35,000 per bear into
northern communities, which until recently has been mostly from
American hunters.[141]

Dogsleds are used for recreational
hunting of polar bears in Canada. Use
of motorized vehicles is forbidden.

The territory of Nunavut accounts for the location 80% of annual kills
in Canada.[138] In 2005, the government of Nunavut increased the
quota from 400 to 518 bears,[141] despite protests from some scientific groups. [142] 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. [143] While most of that quota is hunted
by the indigenous Inuit people, a growing share is sold to recreational hunters. (0.8% in the 1970s, 7.1% in
the 1980s, and 14.6% in the 1990s)[140] Nunavut polar bear biologist, Mitchell Taylor, who was formerly
responsible for polar bear conservation in the territory, insists that bear numbers are being sustained under
current hunting limits.[144] In 2010, the 2005 increase was partially reversed. Government of Nunavut
officials announced that the polar bear quota for the Baffin Bay region would be gradually reduced from 105
per year to 65 by the year 2013.[145] The Government of the Northwest Territories maintain their own quota
of 72 to 103 bears within the Inuvialuit communities of which some are set aside for sports hunters.
Environment Canada also banned the export from Canada of fur, claws, skulls and other products from polar
bears harvested in Baffin Bay as of 1 January 2010. [145]
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. [34] Canada allocates a certain number of
permits each year to sport and subsistence hunting, and those that are not used for sport hunting are
re-allocated to Native subsistence hunting. Whereas Native 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.[34]

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United States
The Marine Mammal Protection Act of 1972 afforded polar bears some protection in the United States. It
banned hunting (except by indigenous substinence hunters), banned importing of polar bear parts (except
polar bear pelts taken legally in Canada), and banned the harassment of polar bears. On 15 May 2008, the
United States department of Interior listed the polar bear as a threatened species under the Endangered
Species Act and banned all importing of polar bear trophies. Importing products made from polar bears had
been prohibited from 1972 to 1994 under the Marine Mammal Protection Act, and restricted between 1994
and 2008. Under those restrictions, permits from the United States Fish and Wildlife Service (FWS) 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. [146]
Since 1994, more than 800 sport-hunted polar bear trophies have been imported into the U.S. [147]

Conservation status, efforts and controversies
Estimates of the status of the global population of polar
bears vary widely. As of 2008, the World Conservation
Union (IUCN) reports that the global population of polar
bears is 20,000 to 25,000, and is declining.[1] In 2006,
the IUCN upgraded the polar bear from a species of least
concern to a vulnerable species.[148] It cited a "suspected
population reduction of >30% within three generations
(45 years)".[1] However, a report published in July 2013,
estimates that the global population of polar bears
increased by an average of almost 4,200 bears since
2001.[149] Risks to the polar bear include climate change,
pollution in the form of toxic contaminants, conflicts
with shipping, stresses from recreational polar-bear
watching, and oil and gas exploration and
development.[1] The IUCN also cited a "potential risk of
over-harvest" through legal and illegal hunting.[1]

This map from the U.S. Geological Survey shows
projected changes in polar bear habitat from 2001 to
2010 and 2041 to 2050. Red areas indicate loss of
optimal polar bear habitat; blue areas indicate gain.

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.[150]

Climate change
The IUCN, 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 species. [30][151][152][153][154][155] The polar bear has
survived several periods warmer than at present. [156]
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.[114] Reduction in sea-ice cover also forces bears to swim longer distances, which
further depletes their energy stores and occasionally leads to drowning.[157] Thinner sea ice tends to deform
more easily, which appears to make it more difficult for polar bears to access seals. [65] Insufficient
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nourishment leads to lower reproductive rates in adult females and lower survival rates in cubs and juvenile
bears, in addition to poorer body condition in bears of all ages. [30]

Mothers and cubs have high
nutritional requirements, which are
not met if the seal-hunting season is
too short.

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.[27] As the distance increases between the pack ice and
the coast, females must swim longer distances to reach favored
denning areas on land.[30] 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. [30]
For the polar bears that currently den on multi-year ice, increased ice
mobility may result in longer distances for mothers and young cubs to
walk when they return to seal-hunting areas in the spring. [30] Diseasecausing bacteria and parasites would flourish more readily in a
warmer climate.[65]

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.[151] Increased human-bear interactions, including fatal attacks on humans, are likely to
increase as the sea ice shrinks and hungry bears try to find food on land. [151][158]
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. [155] The Western
Hudson Bay subpopulation, in a southern part of the range, also
happens to be one of the best-studied polar bear subpopulations. This
subpopulation feeds heavily on ringed seals in late spring, when
newly weaned and easily hunted seal pups are abundant.[143] 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.[143]

Swimming

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. [143] The body
condition of polar bears has declined during this period; the average weight of lone (and likely pregnant)
female polar bears was approximately 290 kg (640 lb) in 1980 and 230 kg (510 lb) in 2004. [143] Between
1987 and 2004, the Western Hudson Bay population declined by 22%. [159]
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. [113][160] In recent years, polar bears in the
Arctic have undertaken longer than usual swims to find prey, resulting in four recorded drownings in the
unusually large ice pack regression of 2005.[157]

Pollution
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 food pyramid, with a diet heavy in blubber
in which halocarbons concentrate, their bodies are among the most contaminated of Arctic mammals. [161]
Halocarbons are known to be toxic to other animals, because they mimic hormone chemistry, and biomarkers
such as immunoglobulin G and retinol suggest similar effects on polar bears. PCBs have received the most

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study, and they have been associated with birth defects and immune system deficiency. [162]
The most notorious of these chemicals, such as PCBs and DDT, have been internationally banned. Their
concentrations in polar bear tissues continued to rise for decades after the ban as these chemicals spread
through the food chain. But 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. [163]

Oil and gas development
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.[1] Because polar bears rely partly on their fur for insulation and soiling of the fur by oil
reduces its insulative value, oil spills put bears at risk of dying from hypothermia.[83] Polar bears exposed to
oil spill conditions have been observed to lick the oil from their fur, leading to fatal kidney failure. [83]
Maternity dens, used by pregnant females and by females with infants, can also be disturbed by nearby oil
exploration and development. Disturbance of these sensitive sites may trigger the mother to abandon her den
prematurely, or abandon her litter altogether. [1]

Predictions
The U.S. Geological Survey predicts two-thirds of the world's polar bears will disappear by 2050, based on
moderate projections for the shrinking of summer sea ice caused by climate change. [65] The bears would
disappear from Europe, Asia, and Alaska, and be depleted from the Arctic archipelago of Canada and areas
off the northern Greenland coast. By 2080, they would disappear from Greenland entirely and from the
northern Canadian coast, leaving only dwindling numbers in the interior Arctic archipelago. [65]
Predictions vary on the extent to which polar bears could adapt to climate change by switching to terrestrial
food sources. Mitchell Taylor, who was director of Wildlife Research for the Government of Nunavut, wrote
to the U.S. Fish and Wildlife Service arguing that local studies are insufficient evidence for global protection
at this time. The letter stated, "At present, the polar bear is one of the best managed of the large Arctic
mammals. If all Arctic nations continue to abide by the terms and intent of the Polar Bear Agreement, the
future of polar bears is secure ... Clearly polar bears can adapt to climate change. They have evolved and
persisted for thousands of years in a period characterized by fluctuating climate." [144] Ken Taylor, deputy
commissioner for the Alaska Department of Fish and Game, has said, "I wouldn't be surprised if polar bears
learned to feed on spawning salmon like grizzly bears." [34]
However, many scientists consider these theories to be naive; [34] it is noted that black and brown bears at
high latitudes are smaller than elsewhere, because of the scarcity of terrestrial food resources. [143] An
additional risk to the species is that if individuals spend more time on land, they will hybridize with brown or
grizzly bears.[155] The IUCN wrote:
Polar bears exhibit low reproductive rates with long generational spans. These factors make
facultative adaptation by polar bears to significantly reduced ice coverage scenarios unlikely.
Polar bears did adapt to warmer climate periods of the past. Due to their long generation time
and the current greater speed of climate change, it seems unlikely that polar bear will be able to
adapt to the current warming trend in the Arctic. If climatic trends continue polar bears may
become extirpated from most of their range within 100 years. [1]

Controversy over species protection

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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. [164][165] Some estimates
of the global population are around 5,000 to 10,000 in the early
1970s;[166] other estimates were 20,000 to 40,000 during the 1980s.
[38][51] Current estimates put the global population at between 20,000
and 25,000.[32]
There are several reasons for the apparent discordance between past
Captive polar bear
and projected population trends: estimates from the 1950s and 1960s
were based on stories from explorers and hunters rather than on
scientific surveys.[167][168] Second, controls of harvesting were introduced that allowed this previously
overhunted species to recover.[167] Third, the recent effects of climate change have affected sea ice
abundance in different areas to varying degrees.[167] Finally, the prediction methods used to predict the
decline in the future population of bears excluded key forecasting principles and included questionable
assumptions.[169]
Debate over the listing of the polar bear under endangered species legislation has put conservation groups
and Canada's Inuit at opposing positions;[34] the Nunavut government and many northern residents have
condemned the U.S. initiative to list the polar bear under the Endangered Species Act. [170][171] Many Inuit
believe the polar bear population is increasing, and restrictions on sport-hunting are likely to lead to a loss of
income to their communities.[34][172]

Protection in the Noth America
The polar bear is protected by many US laws, most naotably the Marine Mammal Protection Act and the
Endangered Species Act

U.S. Marine Mammal Protection Act
Polar bears are protected under the Marine Mammal Protection Act, which prohibits the take (i.e., harass,
hunt, capture, or kill) of all marine mammals. [173]

U.S. Endangered Species Act
On 14 May 2008 the U.S. 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. [174]

Canadian endangered species legislation
In Canada, the Committee on the Status of Endangered Wildlife in Canada recommended in April 2008 that
the polar bear be assessed as a species of special concern under the federal Species at Risk Act (SARA). A
listing would mandate that a management plan be written within five years, a timeline criticized by the World
Wide Fund for Nature as being too long to prevent significant habitat loss from climate change. [175]

In culture
Indigenous folklore
For the indigenous peoples of the Arctic, polar bears have long played an important cultural and material

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role.[125][126] Polar bear remains have been found at hunting sites
dating to 2,500 to 3,000 years ago[128] and 1,500 year old cave
paintings of polar bears have been found in the Chukchi
Peninsula.[126] Indeed, it has been suggested that Arctic peoples'
skills in seal hunting and igloo construction has been in part acquired
from the polar bears themselves.[126]

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Engraving, made by Chukchi carvers
in the 1940s on a walrus tusk, depicts
polar bears hunting walrus.

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 which is said to
resemble a great bear surrounded by dogs came into being. [124] These legends reveal a deep respect for the
polar bear, which is portrayed as both spiritually powerful and closely akin to humans. [124] The human-like
posture of bears when standing and sitting, and the resemblance of a skinned bear carcass to the human body,
have probably contributed to the belief that the spirits of humans and bears were interchangeable. [124]
Eskimo legends tell of humans learning to hunt from the polar bear.
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, a feast was held in the hunting camp in its honor. In order to appease the spirit of
the bear, there were traditional song and drum music and the skull would be ceremonially fed and offered a
pipe.[176] Only once the spirit was appeased would the skull be separated from the skin, taken beyond the
bounds of the homestead, and placed in the ground, facing north. [126] Many of these traditions have faded
somewhat in time, especially in light of the total hunting ban in the Soviet Union (and now Russia) since
1955.
The Nenets of north-central Siberia placed particular value on the talismanic power of the prominent canine
teeth. They 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).[126] The skulls of killed polar bears were buried at specific sacred sites and
altars, called sedyangi, were constructed out of the skulls. Several such sites have been preserved on the
Yamal Peninsula.[126]

Symbols and mascots
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 Toonie (two-dollar coin) features the image of a polar bear and both
the Northwest Territories and Nunavut license plates in Canada are in the
shape of a polar bear. The polar bear is the mascot of Bowdoin College in
Maine and the University of Alaska Fairbanks (see also Alaska Nanooks) and
was chosen as mascot for the 1988 Winter Olympics held in Calgary.
Companies such as Coca-Cola, Polar Beverages, Nelvana, Bundaberg Rum or
Good Humor-Breyers have used images of the polar bear in advertising, [177]
while Fox's Glacier Mints have featured a polar bear named Peppy as the
brand mascot since 1922.

Fiction
Polar bears are also popular in fiction, particularly in books aimed at children
or teenagers. For example, The Polar Bear Son is adapted from a traditional

Coat of arms of the
Chukotka Autonomous
Okrug in the Russian
Federation

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Inuit tale.[178] Polar bears feature prominently in East (also released as North
Child) by Edith Pattou,[179] The Bear by Raymond Briggs (adapted into an
animated short in 1998),[180] and Chris d'Lacey's The Fire Within series.[181]
The panserbjørne of Philip Pullman's fantasy trilogy His Dark Materials are
sapient, dignified polar bears who exhibit anthropomorphic qualities, and
feature prominently in the 2007 film adaptation of The Golden Compass.[182]
The television series Lost features polar bears living on the tropical island
setting.[183]

See also
Arctic National Wildlife Refuge
List of solitary animals
Polar Bears International

Coat of arms of the
Greenlandic Self-Rule
government (Kalaallit
Nunaat)

Notes
1. ^ a b c d e f g h i j k Schliebe, S., Wiig, Ø., Derocher, A. & Lunn, N. (IUCN SSC Polar Bear Specialist Group)
(2008). "Ursus maritimus" (http://www.iucnredlist.org/details/22823). IUCN Red List of Threatened Species.
Version 2013.1. International Union for Conservation of Nature. Retrieved 2013-07-24.
2. ^ Phipps, pg. 185
3. ^ "Polar bear, (Ursus maritimus)" (http://www.fws.gov/endangered/esa-library/pdf/polar_bear.pdf) (PDF). United
States Fish and Wildlife service. Retrieved 9 September 2009. "Appearance. 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."
(Overview page (http://ecos.fws.gov/speciesProfile/SpeciesReport.do?spcode=A0IJ))
4. ^ Kindersley, Dorling (2001). Animal. New York City: DK Publishing. ISBN 0-7894-7764-5.
5. ^ Wozencraft, W. C. (2005). "Order Carnivora" (http://www.bucknell.edu/msw3/browse.asp?id=14000987). In
Wilson, D. E.; Reeder, D. M. Mammal Species of the World (http://www.google.com/books?id=JgAMbNSt8ikC&
pg=PA589) (3rd ed.). Johns Hopkins University Press. p. 589. ISBN 978-0-8018-8221-0. OCLC 62265494
(https://www.worldcat.org/oclc/62265494).
6. ^ Gunderson, Aren (2007). "Ursus Maritimus" (http://animaldiversity.ummz.umich.edu/site/accounts/information
/Ursus_maritimus.html). Animal Diversity Web. University of Michigan Museum of Zoology. Retrieved
27 October 2007.
7. ^ a b IUCN Polar Bear Specialist Group, 2009.15th meeting of PBSG in Copenhagen, Denmark 2009: Press
Release (http://pbsg.npolar.no/en/meetings/press-releases/15-Copenhagen.html). Retrieved 10 January 2010.
8. ^ Kidd, D.A. (1973). Collins Latin Gem Dictionary. London: Collins. ISBN 0-00-458641-7.
9. ^ The Marine Mammal Center (https://web.archive.org/web/20090604063108/http:
//www.marinemammalcenter.org/learning/education/mammalinfo/polarbear.asp)
10. ^ The Arctic Sounder (http://www.thearcticsounder.com/news/show/1309)
11. ^ The fourth world: the heritage of the Arctic and its destruction, Sam Hall, Vintage Books, 1988, pp. 29, 232.
12. ^ "Этимологический Словарь — Piotr Czerwinski — Oshkuy" (http://www.nicomant.fils.us.edu.pl/jrn/2000
/j12/pril/etim-zv.html). Nicomant.fils.us.edu.pl. Retrieved 20 March 2011.

5.2.2015 19:36

Polar bear - Wikipedia, the free encyclopedia

20 од 31

http://en.wikipedia.org/wiki/Polar_bear

13. ^ "Grand Quebec" (http://grandquebec.com/faune-quebecoise/ours-polaire). Grand Quebec. Retrieved 20 March
2011.
14. ^ This combines the Ancient Greek words thalassa/θαλασσα 'sea', and arctos/αρκτος 'bear' and also, with
reference to Ursa Major, 'northern' or 'of the north pole' Liddell, Henry George and Robert Scott (1980). A GreekEnglish Lexicon (Abridged Edition). United Kingdom: Oxford University Press. ISBN 0-19-910207-4.
15. ^ Nakagome et al., Shigeki (2008). "Unequal Rates of Y Chromosome Gene Divergence during Speciation of the
Family Ursidae.". Molecular biology and evolution 25 (7): 1344–1356.
16. ^ Wayne et al., RK (1991). "Molecular distance and divergence time in carnivores and primates.". Mol Biol Evol
9: 297–319.
17. ^ a b Lindqvist, Charlotte; Schuster, Stephan C.; Sun, Yazhou; Talbot, Sandra L.; Qi, Ji; Ratan, Aakrosh; Tomsho,
Lynn P.; Kasson, Lindsay et al. (2010). "Complete mitochondrial genome of a Pleistocene jawbone unveils the
origin of polar bear" (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2841953). Proceedings of the National
Academy of Sciences 107 (11): 5053–5057. doi:10.1073/pnas.0914266107 (https://dx.doi.org
/10.1073%2Fpnas.0914266107). PMC 2841953 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2841953).
PMID 20194737 (https://www.ncbi.nlm.nih.gov/pubmed/20194737).
18. ^ Kurten 1964
19. ^ a b c DeMaster, Douglas P.; Stirling, Ian (8 May 1981). "Ursus Maritimus". Mammalian Species 145 (145): 1–7.
doi:10.2307/3503828 (https://dx.doi.org/10.2307%2F3503828). JSTOR 3503828 (https://www.jstor.org/stable
/3503828). OCLC 46381503 (https://www.worldcat.org/oclc/46381503).
20. ^ Kurtén, B (1964). "The evolution of the polar bear, Ursus maritimus Phipps.". Acta Zoologica Fennica 108:
1–30.
21. ^ Lisette P. Waits, Sandra L. Talbot, R. H. Ward and G. F. Shields (April 1998). "Mitochondrial DNA
phylogeography of the North American brown bear and implications for conservation"
(http://www.cnrhome.uidaho.edu/documents/Waits%20et%20al%201998%20cb.pdf&pid=78496&doc=1).
Conservation Biology. pp. 408–417. Retrieved 1 August 2006.
22. ^ Marris, E. (2007). "Linnaeus at 300: The species and the specious". Nature 446 (7133): 250–253.
doi:10.1038/446250a (https://dx.doi.org/10.1038%2F446250a). PMID 17361153 (https://www.ncbi.nlm.nih.gov
/pubmed/17361153).
23. ^ Edwards CJ, Suchard MA, Lemey P, Welch JJ, Barnes I et al. (2011). "Ancient hybridization and an Irish origin
for the modern polar bear matriline". Current Biology 21 (15): 1251–8. doi:10.1016/j.cub.2011.05.058
(https://dx.doi.org/10.1016%2Fj.cub.2011.05.058). PMID 21737280 (https://www.ncbi.nlm.nih.gov/pubmed
/21737280).
24. ^ Hailer F, Kutschera V, Hallström BM, Klassert D, Fain SR, Leonard JA, Arnason U, Janke A (2012). "Nuclear
genomic sequences reveal that polar bears are an old and distinct bear lineage". Science 336 (6079): 344–347.
doi:10.1126/science.1216424 (https://dx.doi.org/10.1126%2Fscience.1216424). PMID 22517859
(https://www.ncbi.nlm.nih.gov/pubmed/22517859).
25. ^ Miller W, Schuster SC, Welch AJ, et al. (July 2012). "Polar and brown bear genomes reveal ancient admixture
and demographic footprints of past climate change" (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3437856).
Proc Natl Acad Sci U S A 109 (36): E2382–90. doi:10.1073/pnas.1210506109 (https://dx.doi.org
/10.1073%2Fpnas.1210506109). PMC 3437856 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3437856).
PMID 22826254 (https://www.ncbi.nlm.nih.gov/pubmed/22826254).
26. ^ a b Gorman J (23 July 2012). "Brown bears and polar bears split up, but continued coupling"
(http://www.nytimes.com/2012/07/24/science/brown-bears-and-polar-bears-split-up-but-continued-coupling.html).
The New York Times. Retrieved 24 July 2012.

5.2.2015 19:36

Polar bear - Wikipedia, the free encyclopedia

21 од 31

http://en.wikipedia.org/wiki/Polar_bear

27. ^ a b Schliebe, Scott; Evans, Thomas; Johnson, Kurt; Roy, Michael; Miller, Susanne; Hamilton, Charles; Meehan,
Rosa; Jahrsdoerfer, Sonja (21 December 2006). Range-wide status review of the polar bear (Ursus maritimus)
(http://alaska.fws.gov/fisheries/mmm/polarbear/pdf/Polar_Bear_%20Status_Assessment.pdf) (PDF). Anchorage,
Alaska: United States Fish and Wildlife Service. Retrieved 31 October 2007.
28. ^ a b c d e f g h Stirling, Ian (1988). "The First Polar Bears". Polar Bears. Ann Arbor: University of Michigan
Press. ISBN 0-472-10100-5.
29. ^ Rice, Dale W. (1998). Marine Mammals of the World: Systematics and Distribution. Special Publications of the
Society for Marine Mammals 4. Lawrence, Kansas: The Society for Marine Mammalogy. ISBN 1-891276-03-4.
30. ^ a b c d e f g h Derocher, Andrew E.; Lunn, Nicholas J.; Stirling, Ian (2004). "Polar bears in a Warming Climate".
Integrative and Comparative Biology 44 (2): 163–176. doi:10.1093/icb/44.2.163 (https://dx.doi.org
/10.1093%2Ficb%2F44.2.163). PMID 21680496 (https://www.ncbi.nlm.nih.gov/pubmed/21680496).
31. ^ a b c d Polar Bears and Conservation (http://www.polarbearsinternational.org/bear-facts/) and "Polar bear FAQ"
(http://www.polarbearsinternational.org/faq/). Polar Bears International. Retrieved 14 July 2009.
32. ^ a b c d e Aars, pp. 33–55.
33. ^ Paetkau, S.; Amstrup, C.; Born, E. W.; Calvert, W.; Derocher, AE; Garner, GW; Messier, F; Stirling, I et al.
(1999). "Genetic structure of the world's polar bear populations" (http://www.webcitation.org/5nwzesvko) (PDF).
Molecular Ecology 8 (10): 1571–1584. doi:10.1046/j.1365-294x.1999.00733.x (https://dx.doi.org
/10.1046%2Fj.1365-294x.1999.00733.x). PMID 10583821 (https://www.ncbi.nlm.nih.gov/pubmed/10583821).
Archived from the original (http://www.biology.ualberta.ca/faculty/andrew_derocher/uploads/abstracts
/Paetkau_et_al_1999.pdf) on 3 March 2010. Retrieved 17 November 2007.
34. ^ a b c d e f g h i j Campbell, Colin; Lunau, Kate (25 January 2008). "The war over the polar bear: Who's telling the
truth about the fate of a Canadian icon?" (http://www.macleans.ca/science/environment
/article.jsp?content=20080123_5242_5242&page=1). Maclean's. Retrieved 9 March 2008.
35. ^ Aars, pp. 61–62
36. ^ Stirling, Ian (1988). "Introduction". Polar Bears. Ann Arbor: University of Michigan Press.
ISBN 0-472-10100-5.
37. ^ Bernd G. Würsig; J. G. M. Thewissen (2002). Encyclopedia of Marine Mammals (http://books.google.com
/books?id=TwFUimDtz7sC&pg=PA70). Gulf Professional Publishing. p. 70. ISBN 978-0-12-551340-1.
38. ^ a b c d Stirling, Ian (1988). "Distribution and Abundance". Polar Bears. Ann Arbor: University of Michigan
Press. ISBN 0-472-10100-5.
39. ^ Stirling, Ian (January 1997). "The importance of polynyas, ice edges, and leads to marine mammals and birds".
Journal of Marine Systems 10 (1–4): 9–21. doi:10.1016/S0924-7963(96)00054-1 (https://dx.doi.org
/10.1016%2FS0924-7963%2896%2900054-1).
40. ^ Matthews, p. 15
41. ^ "Polar bear, (Ursus maritimus)" (http://web.archive.org/web/20080605045644/http://www.fws.gov/endangered
/factsheets/polar_bear.pdf) (PDF). United States Fish and Wildlife service. Archived from the original
(http://www.fws.gov/endangered/factsheets/polar_bear.pdf) on 5 June 2008. Retrieved 22 March 2008.
"Appearance. 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." (Overview page (http://ecos.fws.gov
/speciesProfile/SpeciesReport.do?spcode=A0IJ))
42. ^ a b Hemstock, p. 4
43. ^ a b c d Wood, G.L. (1983). The Guinness Book of Animal Records. p. 240. ISBN 978-0-85112-235-9.
44. ^ Derocher, A. E., & Wiig, Ø. (2002). Postnatal growth in body length and mass of polar bears (Ursus maritimus)
at Svalbard. Journal of Zoology, 256(3), 343–349.

5.2.2015 19:36

Polar bear - Wikipedia, the free encyclopedia

22 од 31

http://en.wikipedia.org/wiki/Polar_bear

45. ^ Ferguson, S. H., Taylor, M. K., Born, E. W., Rosing-Asvid, A., & Messier, F. (1999). Determinants of home
range size for polar bears (Ursus maritimus). Ecology Letters, 2(5), 311–318.
46. ^ Perrin, William F.; Bernd Würsig; J. G. M. Thewissen (2008). Encyclopedia of Marine Mammals
(http://books.google.com/?id=2rkHQpToi9sC&pg=PA1009) (2 ed.). San Diego, CA: Academic Press. p. 1009.
ISBN 978-0-12-373553-9.
47. ^ Polar bear Ursus maritimus – Appearance/Morphology: Measurement and Weight (Literature Reports)
(http://wildlife1.wildlifeinformation.org/s/0MCarnivor/ursidae/ursus/Ursus_maritimus
/01ursus_maritimusamwtht.html). Wildlife1.wildlifeinformation.org. Retrieved 15 September 2011.
48. ^ "Polar Bear Ursus maritimus – APPEARANCE/ MORPHOLOGY: TAIL" (http://wildpro.twycrosszoo.org
/S/0MCarnivor/ursidae/ursus/Ursus_maritimus/04Ursus_maritimusAMTail.htm). Wildpro. Retrieved 2013-07-01.
49. ^ a b c Lockwood, pp. 10–16
50. ^ "Fractures of the radius and ulna secondary to possible vitamin 'D' deficiency in captive polar bears (Ursus
maritimus)" (http://www.polarbearsinternational.org/pbhc/fractures.htm). Retrieved 25 November 2007.
51. ^ a b c d e Stirling, Ian (1988). Polar Bears. Ann Arbor: University of Michigan Press. ISBN 0-472-10100-5.
52. ^ Uspenskii, S. M. (1977). The Polar Bear. Moscow: Nauka.
53. ^ Kolenosky G. B. 1987. Polar bear. pp. 475–485 in Wild furbearer management and conservation in North
America (M. Novak, J. A. Baker, M. E. Obbard, and B. Malloch, eds.). Ontario Fur Trappers Association, North
Bay, Ontario, Canada.
54. ^ Koon, Daniel W. (1998). "Is polar bear hair fiber optic?" (http://www.opticsinfobase.org/abstract.cfm?URI=ao37-15-3198). Applied Optics 37 (15): 3198–3200. doi:10.1364/AO.37.003198 (https://dx.doi.org
/10.1364%2FAO.37.003198). PMID 18273269 (https://www.ncbi.nlm.nih.gov/pubmed/18273269).
55. ^ In unusually warm conditions, the hollow tubes provide an excellent home for algae. 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.
56. ^ Derocher, Andrew E.; Magnus Andersen; Øystein Wiig (2005). "Sexual dimorphism of polar bears"
(http://web.archive.org/web/20110110120300/http://www.biology.ualberta.ca/faculty/andrew_derocher/uploads
/abstracts/Sexual%20dimorphism%20of%20polar%20bears%202005.pdf) (PDF). Journal of Mammalogy 86 (5):
895–901. doi:10.1644/1545-1542(2005)86[895:SDOPB]2.0.CO;2 (https://dx.doi.org
/10.1644%2F1545-1542%282005%2986%5B895%3ASDOPB%5D2.0.CO%3B2). ISSN 1545-1542
(https://www.worldcat.org/issn/1545-1542). JSTOR 4094434 (https://www.jstor.org/stable/4094434).
57. ^ a b Rosing, pp. 20–23
58. ^ Pagano et al., A. Am (2012). "Long-distance swimming by polar bears (Ursus maritimus) of the southern
Beaufort Sea during years of extensive open water". Canadian Journal of Zoology 90: 663–676.
59. ^ Durner et al., George M. (2011). "Consequences of long-distance swimming and travel over deep-water pack ice
for a female polar bear during a year of extreme sea ice retreat". Polar Biology 34: 975–984.
60. ^ a b c d e f g h Stirling, Ian (1988). "Behavior". Polar Bears. Ann Arbor: University of Michigan Press.
ISBN 0-472-10100-5.
61. ^ Polar Bears: VI. Behavior. (http://www.seaworld.org/infobooks/polarbears/pbbehavior.html), SeaWorld.
Retrieved 21 January 2011.
62. ^ a b c d Matthews, pp. 73–88
63. ^ "Arctic Bears" (http://www.pbs.org/wnet/nature/arcticbears/index.html). PBS Nature. 17 February 2008.
http://www.pbs.org/wnet/nature/arcticbears/index.html.
64. ^ a b M. G. Dyck · S. Romberg (2007). "Observations of a wild polar bear (Ursus maritimus) successfully fishing
Arctic charr (Salvelinus alpinus) and Fourhorn sculpin (Myoxocephalus quadricornis)". Polar Biology 30 (12):

5.2.2015 19:36

Polar bear - Wikipedia, the free encyclopedia

23 од 31

http://en.wikipedia.org/wiki/Polar_bear

1625–1628. doi:10.1007/s00300-007-0338-3 (https://dx.doi.org/10.1007%2Fs00300-007-0338-3).
65. ^ a b c d e f Amstrup, Steven C.; Marcot, Bruce G.; Douglas, David C. (2007). Forecasting the range-wide status of
polar bears at selected times in the 21st Century (http://www.usgs.gov/newsroom/special/polar_bears
/docs/USGS_PolarBear_Amstrup_Forecast_lowres.pdf) (PDF). Reston, Virginia: U.S. Geological Survey.
Retrieved 29 September 2007.
66. ^ a b Hemstock, pp. 24–27
67. ^ Best, R.C. (1984). "Best, R. C. (1984), Digestibility of ringed seals by the polar bear.". Can. J. Zool. 63:
1033–1036.
68. ^ "In pictures: Rock climbing polar bears" (http://news.bbc.co.uk/earth/hi/earth_news/newsid_8622000
/8622244.stm). BBC News. 20 April 2010.
69. ^ (Lono 1957
70. ^ Pedersen 1962
71. ^ Rosing-Asvid, A. (2006). The influence of climate variability on polar bear (Ursus maritimus) and ringed seal
(Pusa hispida) population dynamics. Canadian journal of zoology, 84(3), 357–364.
72. ^ a b Derocher, A. E., Wiig, Ø., & Andersen, M. (2002). Diet composition of polar bears in Svalbard and the
western Barents Sea. Polar Biology, 25(6), 448–452.
73. ^ a b c d e f Derocher, Andrew E.; Wiig, Æ Øystein; Andersen, Æ Magnus (2002). "Diet composition of polar bears
in Svalbard and the western Barents Sea." (http://link.springer.com/article/10.1007/s00300-002-0364-0#page-1).
Polar Biology 25: 448–452. Retrieved 21 November 2014.
74. ^ Thiemann, G. W., S. M. Budge, Sara J. Iverson, and I. Stirling (2007). "Unusual fatty acid biomarkers reveal
age-and sex-specific foraging in polar bears (Ursus maritimus).". Canadian Journal of Zoology 85 (4): 505–517.
75. ^ Thiemann, G. W., Budge, S. M., Iverson, S. J., & Stirling, I. (2007). Unusual fatty acid biomarkers reveal
age-and sex-specific foraging in polar bears (Ursus maritimus). Canadian Journal of Zoology, 85(4), 505–517.
76. ^ Thiemann, G. W., Iverson, S. J., Stirling, I., & Obbard, M. E. (2011). Individual patterns of prey selection and
dietary specialization in an Arctic marine carnivore" Oikos 120(10), 1469–1478.
77. ^ Calvert, Wendy; Stirling, Ian (1990). "Interactions between Polar Bears and Overwintering Walruses in the
Central Canadian High Arctic." (http://www.jstor.org/stable/3872939). Bears: Their Biology and Management,
Vol. 8, A Selection of Papers from the Eighth International Conference on Bear Research and Management 9:
351–356. Retrieved 21 November 2014.
78. ^ a b c d e Clarkson, Peter L.; Stirling, Ian (1994). "Polar Bears" (http://icwdm.org/handbook/carnivor/ca_c25.pdf).
In Hygnstrom, Scott E.; Timm, Robert M.; Larson, Gary E. Prevention and Control of Wildlife Damage
(http://icwdm.org/handbook/index.asp). Lincoln: University of Nebraska. pp. C–25 to C–34. Retrieved
13 November 2007.
79. ^ Calvert, Wendy and Stirling, Ian (1990). "Interactions between polar bears and overwintering walruses in the
Central Canadian High Arctic". Bears: Their Biology and Management Vol. 8, A Selection of Papers from the
Eighth International Conference on Bear Research and Management, Victoria, British Columbia, Canada,
February 1989 8: 351–356. doi:10.2307/3872939 (https://dx.doi.org/10.2307%2F3872939). JSTOR 3872939
(https://www.jstor.org/stable/3872939).
80. ^ Macdonald, D.W.; Barrett , P. (1993). Mammals of Europe. New Jersey: Princeton University Press.
ISBN 0-691-09160-9.
81. ^ Heyland, J. D., & Hay, K. (1976). An attack by a polar bear on a juvenile beluga. Arctic, 29(1), 56–57.
82. ^ a b c d Bruemmer, pp. 25–33
83. ^ a b c d Stirling, Ian (1988). "What Makes a Polar Bear Tick?". Polar Bears. Ann Arbor: University of Michigan
Press. ISBN 0-472-10100-5.

5.2.2015 19:36

Polar bear - Wikipedia, the free encyclopedia

24 од 31

http://en.wikipedia.org/wiki/Polar_bear

84. ^ a b Manning, T. H. (March 1961). "Comments on 'Carnivorous walrus and some Arctic zoonoses' "
(http://pubs.aina.ucalgary.ca/arctic/Arctic14-1-76.pdf) (PDF). Arctic 14 (1): 76–77. doi:10.14430/arctic3663
(https://dx.doi.org/10.14430%2Farctic3663). ISSN 0004-0843 (https://www.worldcat.org/issn/0004-0843).
Retrieved 13 November 2007.
85. ^ Lunn, N. J.; Stirling, Ian (1985). "The significance of supplemental food to polar bears during the ice-free
period of Hudson Bay". Canadian Journal of Zoology 63 (10): 2291–2297. doi:10.1139/z85-340
(https://dx.doi.org/10.1139%2Fz85-340).
86. ^ Eliasson, Kelsey (May 2004). "Hudson Bay Post — Goodbye Churchil Dump" (http://www.polarbearalley.com
/churchill-dump.html). Retrieved 9 June 2008.
87. ^ a b c d e f Russell, Richard H (1975). "The Food Habits of Polar Bears of James Bay and Southwest Hudson Bay
in Summer and Autumn". Arctic 28 (2): 117–129.
88. ^ Harington 2008
89. ^ Derocher, A. E., Wiig, Ø., & Bangjord, G. (2000). Predation of Svalbard reindeer by polar bears. Polar Biology,
23(10), 675–678.
90. ^ a b Brook, R. K., & Richardson, E. S. (2002). Observations of polar bear predatory behaviour toward caribou.
Arctic, 193–196.
91. ^ Brook, R. K., and E. S. Richardson (2002). "Observations of polar bear predatory behaviour toward caribou.".
Arctic 55 (2): 193–196.
92. ^ Ovsyanikov, N.G. 1996. Interactions of polar bears with other large mammals, including man. Journal of
Wildlife Research, 1:254–259.
93. ^ Ramsay, M. A.; Hobson, K. A. (May 1991). "Polar bears make little use of terrestrial food webs: evidence from
stable-carbon isotope analysis". Oecologia 86 (4): 598–600. doi:10.1007/BF00318328 (https://dx.doi.org
/10.1007%2FBF00318328).
94. ^ Best, R. C. (1985). "Digestibility of ringed seals by the polar bear". Canadian Journal of Zoology 63 (5):
1033–1036. doi:10.1139/z85-155 (https://dx.doi.org/10.1139%2Fz85-155).
95. ^ Harington, C.R. 2008
96. ^ Bentzen et al., E'H. (2007). "Variation in winter diet of southern Beaufort Sea polar bears inferred from stable
isotope analysis". Canadian Journal of Zoology 85: 596–608.
97. ^ Derocher, Andrew E.; Andriashek, Dennis; Stirling, Ian, Arctic (1993). "Terrestrial Foraging by Polar Bears
During the Ice-Free Period in Western Hudson Bay." (http://www.jstor.org/stable/40511413) 46 (3). pp. 251–254.
Retrieved 21 November 2014.
98. ^ a b Matthews, pp. 27–29
99. ^ a b Stirling, Ian (1988). "Distribution and Abundance". Polar Bears. Ann Arbor: University of Michigan Press.
ISBN 0-472-10100-5.
100. ^ Hoshino, M. Hoshino's Alaska. Chronicle Books (2007), ISBN 0811856518.
101. ^ Matthews, p. 95
102. ^ Bear Behaviour and Activities from Gary Brown's The Great Bear Almanac, Lyons & Burford, Publishers, 1993
103. ^ a b c Rosing, pp. 128–132
104. ^ Why Didn't the Wild Polar Bear eat the Husky? (http://nifplay.org/polar-husky.html) The National Institute for
Play
105. ^ a b c d e f g h i j k l m n o Stirling, Ian (1988). "Reproduction". Polar Bears. Ann Arbor: University of Michigan
Press. ISBN 0-472-10100-5.
106. ^ a b Carpenter, Tom (November–December 2005). "Who's Your Daddy?". Canadian Geographic (Ottawa: The
Royal Canadian Geographic Society): 44–56.

5.2.2015 19:36

Polar bear - Wikipedia, the free encyclopedia

25 од 31

http://en.wikipedia.org/wiki/Polar_bear

107. ^ a b Rosing, pp. 42–48
108. ^ Lockwood, pp.17–21
109. ^ Bruce, D. S.; Darling, N. K.; Seeland, K. J.; Oeltgen, P. R.; Nilekani, S. P.; Amstrup, S. C. (1990). "Is the polar
bear (Ursus maritimus) a hibernator?: Continued studies on opioids and hibernation". Pharmacology Biochemistry
and Behavior 35 (3): 705–711. doi:10.1016/0091-3057(90)90311-5 (https://dx.doi.org
/10.1016%2F0091-3057%2890%2990311-5).
110. ^ "Rejected by their mother, polar cubs now under intensive care at Toronto Zoo"
(http://www.theglobeandmail.com/news/national/toronto/rejected-by-their-mother-polar-cubs-now-underintensive-care-at-toronto-zoo/article2199799/?utm_medium=Feeds%3A%20RSS%2FAtom&utm_source=Home&
utm_content=2199799). 13 October 2011.
111. ^ Derocher, AE and Wiig, Oe; Infanticide and Cannibalism of Juvenile Polar Bears (Ursus maritimus) in Svalbard
(http://pubs.aina.ucalgary.ca/arctic/Arctic52-3-307.pdf) Arctic [Arctic]. Vol. 52, no. 3, pp. 307–310. Sep 1999
112. ^ a b c d e f "Polar bears in depth: Survival" (http://web.archive.org/web/20091208231221/http:
//www.polarbearsinternational.org/polar-bears-in-depth/survival/page3). Polar Bears International. p. 3. Archived
from the original (http://www.polarbearsinternational.org/polar-bears-in-depth/survival/page1/) on 8 December
2009.
113. ^ a b Regehr, Eric V.; Amstrup, Steven C.; Stirling, Ian (2006). Written at Anchorage, Alaska. Polar bear
population status in the Southern Beaufort Sea (http://pubs.usgs.gov/of/2006/1337/pdf/ofr20061337.pdf) (PDF).
Reston, Virginia: U.S. Geological Survey. Open-File Report 2006-1337. Retrieved 15 September 2007.
114. ^ a b Stirling, Ian; Lunn, N. J.; Iacozza, J. (September 1999). "Long-term trends in the population ecology of polar
bears in Western Hudson Bay in relation to climatic change" (http://pubs.aina.ucalgary.ca/arctic
/Arctic52-3-294.pdf) (PDF). Arctic 52 (3): 294–306. doi:10.14430/arctic935 (https://dx.doi.org
/10.14430%2Farctic935). ISSN 0004-0843 (https://www.worldcat.org/issn/0004-0843). Retrieved 11 November
2007.
115. ^ Maternal success appeared to decline after this point, possibly because of an age-related impairment in the
ability to store the fat necessary to rear cubs. Derocher, A.E.; Stirling, I. (1994). "Age-specific reproductive
performance of female polar bears (Ursus maritimus)" (http://md1.csa.com/partners
/viewrecord.php?requester=gs&collection=ENV&recid=3794443&q=Ursus+maritimus+reproduction&
uid=792151267&setcookie=yes). Journal of Zoology 234 (4): 527–536. doi:10.1111/j.1469-7998.1994.tb04863.x
(https://dx.doi.org/10.1111%2Fj.1469-7998.1994.tb04863.x). Retrieved 15 February 2008.
116. ^ Larsen, Thor; Kjos-Hanssen, Bjørn (1983). "Trichinella sp. in polar bears from Svalbard, in relation to hide
length and age". Polar Research 1 (1): 89–96. doi:10.1111/j.1751-8369.1983.tb00734.x (https://dx.doi.org
/10.1111%2Fj.1751-8369.1983.tb00734.x).
117. ^ Hemstock, pp. 29–35
118. ^ Wrigley, Robert E. (Spring 2008). "The Oldest Living Polar Bear" (http://web.archive.org/web/20080626110834
/http://www.polarbearsinternational.org/rsrc/files/pbispring08.pdf) (PDF). Polar Bears International Newsletter.
Polar Bears International. Archived from the original (http://www.polarbearsinternational.org/rsrc/files
/pbispring08.pdf) on 26 June 2008. Retrieved 9 June 2008.
119. ^ Dough O'Harra Polar bears, grizzlies increasingly gather on North Slope (https://web.archive.org
/web/20080401001816/http://dwb.adn.com/front/story/6415667p-6294323c.html). Anchorage Daily News. 24
April 2005
120. ^ "ABC News: Grizzlies encroaching on polar bear Country" (http://abcnews.go.com/Technology/DyeHard
/Story?id=582243&page=3). ABC News. Retrieved 10 October 2009.
121. ^ "Wolf (Canis lupus) predation of a polar bear (Ursus maritimus) cub on the sea ice off Northwestern Banks

5.2.2015 19:36

Polar bear - Wikipedia, the free encyclopedia

26 од 31

http://en.wikipedia.org/wiki/Polar_bear

Island, Northwest Territories, Canada. ARCTIC Vol. 59, No. 3 (September 2006) p. 322–324"
(http://pubs.aina.ucalgary.ca/arctic/Arctic59-3-322.pdf) (PDF). Retrieved 20 March 2011.
122. ^ Mark Allardyce (2000-09-30). Wolverine – A Look Into the Devils Eyes (http://books.google.com
/?id=27ULgtTrfs4C&pg=PA20&dq=wolverines+killing+polar+bears&q=polar%20bear%20). pp. 20, 165.
ISBN 978-1-905361-00-7. Retrieved 8 August 2010.
123. ^ Rosen, Yereth (1 May 2012). "Polar bears can swim vast distances, study finds" (http://www.reuters.com/article
/2012/05/02/us-usa-polarbears-idUSBRE84100W20120502). Reuters. Retrieved 8 May 2012.
124. ^ a b c d Stirling, Ian (1988). "The Original Polar Bear Watchers". Polar Bears. Ann Arbor: University of
Michigan Press. ISBN 0-472-10100-5.
125. ^ a b Lockwood, pp. 6–9
126. ^ a b c d e f g h i j k Uspensky, Savva Mikhailovich (1977). Белый Медведь (tr: Belyi Medved') — (in Russian).
Moscow: Nauka.
127. ^ As a carnivore which feeds largely upon fish-eating carnivores, the polar bear ingests large amounts of vitamin
A, which is stored in their livers. The resulting high concentrations cause Hypervitaminosis A, Rodahl, K.; Moore,
T. (1943). "The vitamin A content and toxicity of bear and seal liver" (https://www.ncbi.nlm.nih.gov/pmc/articles
/PMC1257872). The Biochemical Journal 37 (2): 166–168. PMC 1257872 (https://www.ncbi.nlm.nih.gov
/pmc/articles/PMC1257872). PMID 16747610 (https://www.ncbi.nlm.nih.gov/pubmed/16747610).
128. ^ a b Lockwood, pp. 31–36
129. ^ "Polar Bear Management" (http://web.archive.org/web/20080504105354/http://wildlife.enr.gov.nt.ca
/NWTWildlife/bears/PolarBear/management.htm). Government of the Northwest Territories. Archived from the
original (http://wildlife.enr.gov.nt.ca/NWTWildlife/bears/PolarBear/management.htm) on 4 May 2008. Retrieved
14 March 2008.
130. ^ a b Bruemmer, pp. 93–111
131. ^ "Proceedings of the 2nd Working Meeting of Polar Bear Specialists" (http://web.archive.org
/web/20080504190729/http://pbsg.npolar.no/Meetings/PressReleases/02-Morges.htm). Polar Bears
(http://pbsg.npolar.no/). Morges, Switzerland: IUCN. February 1970. Archived from the original
(http://pbsg.npolar.no/Meetings/PressReleases/02-Morges.htm) on 4 May 2008. Retrieved 24 October 2007.
132. ^ International Agreement on the Conservation of Polar Bears (https://web.archive.org/web/20030409113042
/http://pbsg.npolar.no/ConvAgree/agreement.htm), 15 November 1973, Oslo
133. ^ Stirling, Ian Foreword in Rosing, Norbert (1996). The World of the Polar Bear. Willowdale, ON: Firefly Books
Ltd. ISBN 1-55209-068-X.
134. ^ "U.S. and Russia sign pact to protect the polar bear" (http://query.nytimes.com
/gst/fullpage.html?res=980DE3DD1F3FF934A25753C1A9669C8B63). The New York Times. 17 October 2000.
Retrieved 12 April 2008.
135. ^ "US-Russia Polar Bear Treaty Ratified" (http://www.sciencedaily.com/releases/2007/10/071014202952.htm).
ScienceDaily. 18 October 2007. Retrieved 12 April 2008.
136. ^ a b Steven Lee Myers (16 April 2007). "Russia tries to save polar bears with legal hunt"
(http://www.nytimes.com/2007/04/16/world/europe/16polar.html?_r=1&oref=slogin). The New York Times.
Retrieved 12 April 2008.
137. ^ Naomi A. Rose Hitting Polar Bears When They Are Down (http://www.hsi.org/news/news
/2006/Hitting_polar_bears_when_down_021606.html). The Humane Society of the United States. 16 February
2006
138. ^ a b Aaars, pp. 101–116
139. ^ Freeman, M.M.R.; Wenzel, G.W. (March 2006). "The nature and significance of polar bear conservation hunting

5.2.2015 19:36

Polar bear - Wikipedia, the free encyclopedia

27 од 31

http://en.wikipedia.org/wiki/Polar_bear

in the Canadian Arctic". Arctic 59 (1): 21–30.
140. ^ a b Wenzel, George W. (September 2004). "Polar bear as a resource: An overview" (http://www.nrf.is
/Open%20Meetings/Yellowknife_2004/Wenzel.pdf) (PDF). Yellowknife: 3rd NRF Open Meeting. Retrieved
3 December 2007.
141. ^ a b "Nunavut hunters can kill more polar bears this year" (http://www.cbc.ca/canada/story/2005/01/10/polarbear-hunt050110.html). CBC News. 10 January 2005. Retrieved 15 September 2007.
142. ^ "Rethink polar bear hunt quotas, scientists tell Nunavut hunters" (http://www.cbc.ca/health/story/2005/07
/04/polar-bears050704.html). CBC News. 4 July 2005. Retrieved 20 March 2011.
143. ^ a b c d e f Stirling, Ian; Derocher, Andrew E. (2007). "Melting under pressure: The real scoop on climate
warming and polar bears" (http://www.polarbearsinternational.org/sites/default/files/scientists
/stirling_derocher_climate_wildlife_professional_2007.pdf) (PDF). The Wildlife Professional (Fall 2007) 1 (3):
24–27, 43. Retrieved 17 November 2007.
144. ^ a b Taylor, Mitchell K. (6 April 2006). "Review of CBD Petition" (http://www.ff.org/centers/csspp
/pdf/200701_taylor.pdf) (PDF). Letter to the U.S. Fish and Wildlife Service. Retrieved 8 September 2007.
145. ^ a b George, Jane (April 2010). "Nunavut hunters still enraged over bear quotas" (http://www.nunatsiaqonline.ca
/stories/article/8976_nunavut_hunters_still_enraged_over_bear_quotas/). Iqaluit. Retrieved 4 April 2010.
146. ^ "Bear Facts: Harvesting/Hunting" (http://www.polarbearsinternational.org/bear-facts/hunting/). Polar Bears
International. Retrieved 14 March 2008.
147. ^ The Humane Society of the United States "Support the Polar Bear Protection Act" (https://community.hsus.org
/campaign/FED_2007_polar_bear_trophy)
148. ^ "Release of the 2006 IUCN Red List of Threatened Species reveals ongoing decline of the status of plants and
animals" (http://web.archive.org/web/20060512071333/http://www.iucn.org/en/news/archive/2006/05
/02_pr_red_list_en.htm). World Conservation Union. Archived from the original (http://www.iucn.org/en/news
/archive/2006/05/02_pr_red_list_en.htm) on 12 May 2006. Retrieved 1 February 2006.
149. ^ "Global population of polar bears has increased by 2,650 to 5,700 since 2001" (http://polarbearscience.com
/2013/07/15/global-population-of-polar-bears-has-increased-by-2650-5700-since-2001/). Polar Bear Science.
Retrieved 30 September 2013.
150. ^ WWF: A Leader in Polar Bear Conservation . Retrieved 29 June 2009, from WFF – Polar Bear Web site:
http://www.worldwildlife.org/species/finder/polarbear/polarbear.html#
151. ^ a b c Stirling, Ian; Claire L. Parkinson (September 2006). "Possible effects of climate warming on selected
populations of polar bears (Ursus maritimus) in the Canadian Arctic" (http://www.nasa.gov
/pdf/157360main_StirlingParkinson2006_Arctic59-3-261.pdf) (PDF). Arctic 59 (3): 261–275. ISSN 0004-0843
(https://www.worldcat.org/issn/0004-0843). Retrieved 15 September 2007.
152. ^ Stirling, Ian; N.J. Lunn, John Iacozza, Campbell Elliott and Martyn Obbard (March 2004). "Polar bear
distribution and abundance on the Southwestern Hudson Bay coast during open water season, in relation to
population trends and annual ice patterns" (http://umanitoba.ca/ceos/files/publications_pdf/058.pdf) (PDF). Arctic
57 (1): 15–26. doi:10.14430/arctic479 (https://dx.doi.org/10.14430%2Farctic479). ISSN 0004-0843
(https://www.worldcat.org/issn/0004-0843). Retrieved 15 September 2007.
153. ^ Barber, D.G.; J. Iacozza (March 2004). "Historical analysis of sea ice conditions in M'Clintock Channel and the
Gulf of Boothia, Nunavut: implications for ringed seal and polar bear habitat" (http://goliath.ecnext.com/coms2
/gi_0199-263435/Historical-analysis-of-sea-ice.html) (PDF). Arctic 57 (1): 1–14. doi:10.14430/arctic478
(https://dx.doi.org/10.14430%2Farctic478). ISSN 0004-0843 (https://www.worldcat.org/issn/0004-0843).
154. ^ T. Appenzeller and D. R. Dimick, "The Heat is On," National Geographic 206 (2004): 2–75. cited in Flannery,
Tim (2005). The Weather Makers. Toronto, Ontario: HarperCollins. pp. 101–103. ISBN 0-00-200751-7.

5.2.2015 19:36

Polar bear - Wikipedia, the free encyclopedia

28 од 31

http://en.wikipedia.org/wiki/Polar_bear

155. ^ a b c Arctic Climate Impact Assessment (2004). Impact of a Warming Arctic: Arctic Impact Climate Assessment
(http://amap.no/workdocs/index.cfm?dirsub=%2FACIA%2Foverview). Cambridge: Cambridge University Press.
ISBN 0-521-61778-2. OCLC 56942125 (https://www.worldcat.org/oclc/56942125).. The relevant paper is Key
Finding 4 (http://amap.no/workdocs/index.cfm?action=getfile&dirsub=%2FACIA%2Foverview&
filename=Finding4.pdf&CFID=1282&CFTOKEN=1454CA86-1283-9480-2B88165DE19F817F&sort=default)
156. ^ Cronin, Matthew Anthony; McDonough, Molly M.; H. M. Huynh, and Robert J. Baker. (2013). "Genetic
relationships of North American bears (Ursus) inferred from amplified fragment length polymorphisms and
mitochondrial DNA sequences." (http://www.nrcresearchpress.com/doi/abs/10.1139/cjz-2013-0078). Canadian
Journal of Zoology 91 (9): 626-634. Retrieved 13 January 2015.
157. ^ a b Monnett, Charles; Gleason, Jeffrey S. (July 2006). "Observations of mortality associated with extended
open-water swimming by polar bears in the Alaskan Beaufort Sea". Polar Biology 29 (8): 681–687.
doi:10.1007/s00300-005-0105-2 (https://dx.doi.org/10.1007%2Fs00300-005-0105-2).
158. ^ Mitchell Taylor, a former polar bear researcher for the Nunavut government, believes that arctic warming has
been caused by natural phenomena and is not a long-term threat to the polar bear. After his retirement, he was not
re-appointed to the international Polar Bear Specialist Group (PBSG), giving rise to speculation that he was
excluded from the group because of his views on climate change. According to the PBSG chair, appointments to
the PBSG are given to scientists who are currently active in polar bear research, and that as a retired researcher
Taylor did not qualify. (References: Booker, Christopher (27 June 2009). "Polar bear expert barred by global
warmists" (http://www.telegraph.co.uk/comment/columnists/christopherbooker/5664069/Polar-bear-expert-barredby-global-warmists.html). The Daily Telegraph (London). Retrieved 12 August 2009.)
159. ^ Regehr, E. V.; Lunn, N. J.; Amstrup, N. C.; Stirling, I. (2007). "Effects of earlier sea ice breakup on survival and
population size of polar bears in western Hudson Bay". Journal of Wildlife Management 71 (8): 2673–2683.
doi:10.2193/2006-180 (https://dx.doi.org/10.2193%2F2006-180).
160. ^ 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. Thus now the Alaskan population more resembles the world population in
that it is more likely to den on land. Fischbach, A. S.; Amstrup, S. C.; Douglas, D. C. (2007). "Landward and
eastward shift of Alaskan polar bear denning associated with recent sea ice changes". Polar Biology 30 (11):
1395–1405. doi:10.1007/s00300-007-0300-4 (https://dx.doi.org/10.1007%2Fs00300-007-0300-4).
161. ^ "Polar Bears at the Top of POPs" (http://www.arctic.uoguelph.ca/cpl/arcticnews/articles/PolarBears
/PolarBear.htm). The Science and the Environment Bulletin. Environment Canada. May–June 2000. Retrieved
20 October 2008.
162. ^ Skaare, Janneche Utne et al. (2002). "Ecological risk assessment of persistent organic pollutants in the arctic"
(http://www.webcitation.org/5nwzfou68) (PDF). Toxicology. 181–182: 193–197.
doi:10.1016/S0300-483X(02)00280-9 (https://dx.doi.org/10.1016%2FS0300-483X%2802%2900280-9).
PMID 12505309 (https://www.ncbi.nlm.nih.gov/pubmed/12505309). Archived from the original
(http://www.biology.ualberta.ca/faculty/andrew_derocher/uploads/abstracts/Skaare_et_al_2002.pdf) on 3 March
2010. Retrieved 17 November 2007.
163. ^ Verreault, Jonathan et al. (2005). "Chlorinated hydrocarbon contaminants and metabolites in polar bears (Ursus
maritimus) from Alaska, Canada, East Greenland, and Svalbard: 1996–2002" (http://www.webcitation.org
/5nwzfqHtP) (PDF). Science of the Total Environment. 351–352: 369–390. doi:10.1016/j.scitotenv.2004.10.031
(https://dx.doi.org/10.1016%2Fj.scitotenv.2004.10.031). PMID 16115663 (https://www.ncbi.nlm.nih.gov/pubmed
/16115663). Archived from the original (http://www.biology.ualberta.ca/faculty/andrew_derocher/uploads
/abstracts/Verreault%20et%20al%20STOTEN%202005.pdf) on 3 March 2010. Retrieved 17 November 2007.
164. ^ "Marine Mammals Management: Polar Bear" (http://alaska.fws.gov/fisheries/mmm/polarbear/pbmain.htm).

5.2.2015 19:36

Polar bear - Wikipedia, the free encyclopedia

29 од 31

http://en.wikipedia.org/wiki/Polar_bear

U.S. Fish and Wildlife Service, Alaska. Retrieved 9 June 2008.
165. ^ "WWF — Polar bear status, distribution & population" (http://www.panda.org/what_we_do/where_we_work
/arctic/area/species/polarbear/population/). World Wildlife Foundation. Retrieved 22 March 2010.
166. ^ Krauss, Clifford (27 May 2006). "Bear hunting caught in global warming debate" (http://www.nytimes.com
/2006/05/27/world/americas/27bears.html). The New York Times. Retrieved 11 March 2008.
167. ^ a b c Derocher, Andrew. "Ask the experts: Are polar bear populations increasing?"
(http://www.polarbearsinternational.org/ask-the-experts/population/). Polar Bears International. Retrieved
9 March 2008.
168. ^ Bruemmer, p. 101. In a meeting of the five circumpolar nations on 6 September 1965, estimates of the
worldwide population ranged from 5,000 to 19,000. "The truth was, no one knew... Scientific research had been
sketchy and knowledge of the polar bear was based largely on stories brought back by explorers and hunters."
169. ^ J. Scott Armstrong and Kesten C. Greene and Willie Soon (2008). "Polar bear population forecasts: A publicpolicy forecasting audit" (http://qbox.wharton.upenn.edu/documents/mktg/research/1526-551x2008-38-05-0382-2au-copy.pdf). Interfaces (INFORMS) 38 (5): 382–405. doi:10.1287/inte.1080.0383
(https://dx.doi.org/10.1287%2Finte.1080.0383).
170. ^ "Nunavut MLAs condemn U.S. proposal to make polar bears threatened species" (http://www.cbc.ca/canada
/north/story/2007/06/04/nu-pbear.html). CBC News. 4 June 2007. Retrieved 15 September 2007.
171. ^ "Inuit reject U.S. polar bear proposal" (http://www.cbc.ca/canada/north/story/2007/06/21/polar-bears.html).
CBC News. 21 June 2007. Retrieved 15 September 2007.
172. ^ Northern Research Forum. Polar bear as a resource (http://www.nrf.is/Open%20Meetings/Yellowknife_2004
/Wenzel.pdf). A position paper presented for the 3rd NRF Open Meeting in Yellowknife and Rae Edzo, Canada.
15–18 September 2004
173. ^ US Fish & Wildlife Service. "Environmental Conservation Online System" (http://ecos.fws.gov/speciesProfile
/profile/speciesProfile.action?spcode=A0IJ).
174. ^ US Fish & Wildlife Service. "Environmental Conservation Online System" (http://ecos.fws.gov/speciesProfile
/profile/speciesProfile.action?spcode=A0IJ).
175. ^ Brach, Bal (25 April 2008). "Experts seek more protection for polar bears" (http://www.canada.com/topics
/news/national/story.html?id=eaeb2409-16eb-4227-9fca-0e6e955917c8&k=98911). Canwest News Service.
Retrieved 9 May 2008.
176. ^ Kochnev AA, Etylin VM, Kavry VI, Siv-Siv EB, Tanko IV (17–19 December 2002). "Ritual Rites and Customs
of the Natives of Chukotka connected with the Polar Bear". Preliminary report submitted for the meeting of the
Alaska Nanuuq Commission (Nome, Alaska, USA). pp. 1–3.
177. ^ "Bundaberg Rum Web site — history section" (http://www.bundabergrum.com.au/flash/home.htm). Bundaberg
Rum Web site. Retrieved 26 March 2008.
178. ^ Dabcovich, Lydia (1997). The polar bear son: An Inuit tale. New York: Clarion Books. ISBN 0-395-72766-9.
179. ^ East (2003), A novel by Edith Pattou (http://www.fantasticfiction.co.uk/p/edith-pattou/east.htm), Fantastic
Fiction
180. ^ The Bear (http://www.toonhound.com/briggsthebear.htm), Toonhound
181. ^ The Fire Within (http://www.icefire.co.uk/Books/thefirewithin.html), Chris d'Lacey's official website
182. ^ "The Golden Compass: The Bear Facts" (http://www.cgsociety.org/index.php/CGSFeatures/CGSFeatureSpecial
/golden_compass_the_bear_facts). CG Society. Retrieved 2014-03-17.
183. ^ Abrams, Natalie (31 January 2010). "13 Questions with the Producers of Lost: Polar Bears, the Smoke Monster,
and the Man in Black" (http://www.tvguide.com/news/lost-producers-questions-1014514.aspx). TV Guide.
Retrieved 17 March 2014.

5.2.2015 19:36

Polar bear - Wikipedia, the free encyclopedia

30 од 31

http://en.wikipedia.org/wiki/Polar_bear

References
Aars, Jon, ed. (June 2005). "Polar Bears" (http://web.archive.org/web/20080409082137/http:
//pbsg.npolar.no/docs/PBSG14proc.pdf) (PDF). 14th Working Meeting of the IUCN/SSC Polar Bear
Specialist Group 32. Nicholas J. Lunn and Andrew E. Derocher. Seattle, Washington, United States:
IUCN. ISBN 2-8317-0959-8. Archived from the original (http://pbsg.npolar.no/docs/PBSG14proc.pdf)
on 9 April 2008. Retrieved 19 April 2008.
Bruemmer, Fred (1989). World of the Polar Bear. Toronto, Ontario, Canada: Key Porter Books.
ISBN 1-55013-107-9.
Hemstock, Annie (1999). The Polar Bear. Manakato, MN: Capstone Press. ISBN 0-7368-0031-X.
Lockwood, Sophie (2006). Polar Bears. Chanhassen, MN: The Child's World. ISBN 1-59296-501-6.
Matthews, Downs (1993). Polar Bear. San Francisco, CA: Chronicle Books.
ISBN 978-0-8118-0204-8.
Phipps, John (1774). A voyage towards the North Pole undertaken by His Majesty's command, 1773
(http://www.biodiversitylibrary.org/page/628763). London: W. Bowyer and J. Nicols, for J. Nourse.
Retrieved 8 September 2008.
Rosing, Norbert (1996). The World of the Polar Bear. Willowdale, ON: Firefly Books Ltd.
ISBN 1-55209-068-X.

External links
View occurrences of Ursus maritimus
(http://www.biodiversitylibrary.org/name/Ursus_maritimus) in
Biodiversity Heritage Library.
National Wildlife Federation's Polar Bear Page
(http://www.nwf.org/polarbear)

Wikimedia Commons has
media related to Ursus
maritimus.
Wikispecies has
information related to:
Ursus maritimus

ARKive — images and movies of the polar bear (Ursus
maritimus) (http://www.arkive.org/species/GES/mammals/Ursus_maritimus/)
Smithsonian National Museum of Natural History species account-Polar Bear (http://www.mnh.si.edu
/mna/image_info.cfm?species_id=418)
USGS Polar Bear Studies (http://www.usgs.gov/newsroom/special/polar%5Fbears/)
Map of polar bear ranges and denning areas in Nunavut from Nunavut Planning Commission
(http://www.nunavut.ca/en/map?zoom=0&lat=69.59292&lon=-86.95845&
layers=BTFTTFFFFFFFFFFFFTFFFFFFTTT)
BBC Nature: Polar bear news, and video clips from BBC programmes past and present.
(http://www.bbc.co.uk/nature/life/Polar_bear)
Photos, facts, videos from Polar Bears International which funds population, preservation and DNA
studies of the polar bear (http://www.polarbearsinternational.org/)
Map: Here's where the polar bears are vanishing (http://www.vox.com/2014/12/18/7415843/polarbears-vanishing)

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Retrieved from "http://en.wikipedia.org/w/index.php?title=Polar_bear&oldid=642766156"
Categories: IUCN Red List vulnerable species Polar bears Animals described in 1774 Inuit culture
Mammals of Asia Mammals of Canada Mammals of Europe Mammals of the Arctic
Mammals of the United States Mammals of Greenland Holarctic fauna Megafauna of Eurasia
Megafauna of North America Vulnerable fauna of the United States Vulnerable animals
Fauna of Siberia Megafauna of North Asia

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