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68-451: The polar bear is a large bear native to the Arctic and nearby areas. Polar Bear may also refer to: Polar bear Ursus eogroenlandicus Ursus groenlandicus Ursus jenaensis Ursus labradorensis Ursus marinus Ursus polaris Ursus spitzbergensis Ursus ungavensis Thalarctos maritimus The polar bear ( Ursus maritimus ) is a large bear native to

136-487: A decline in sea ice , giving the polar bear less access to its favoured prey and increasing the risk of malnutrition and starvation. Less sea ice also means that the bears must spend more time on land, increasing conflicts with people. Polar bears have been hunted, both by native and non-native peoples, for their coats, meat and other items. They have been kept in captivity in zoos and circuses and are prevalent in art, folklore, religion and modern culture. The polar bear

204-495: A " Roman nose ". They have 34–42 teeth including 12 incisors , 4 canines , 8–16 premolars and 10 molars . The teeth are adapted for a more carnivorous diet than that of the brown bear, having longer, sharper and more spaced out canines, and smaller, more pointed cheek teeth (premolars and molars). The species has a large space or diastema between the canines and cheek teeth, which may allow it to better bite into prey. Since it normally preys on animals much smaller than it,

272-500: A 2011 study concluded that living polar bear populations derived their maternal lines from now-extinct Irish brown bears. Later studies have clarified that gene flow went from polar to brown bears rather than the reverse. Up to 9 percent of the genome of ABC bears was transferred from polar bears, while Irish bears had up to 21.5 percent polar bear origin. Mass hybridization between the two species appears to have stopped around 200,000 years ago. Modern hybrids are relatively rare in

340-419: A bear spots a seal hauling out on the sea ice, it slowly stalks it with the head and neck lowered, possibly to make its dark nose and eyes less noticeable. As it gets closer, the bear crouches more and eventually charges at a high speed, attempting to catch the seal before it can escape into its ice hole. Some stalking bears need to move through water; traversing through water cavities in the ice when approaching

408-588: A carcass when they see an adult male approaching, though are less likely to if they have not eaten in a long time. Whale carcasses are a valuable food source, particularly on land and after the sea ice melts, and attract several bears. In one area in northeastern Alaska, polar bears have been recorded competing with grizzly bears for whale carcasses. Despite their smaller size, grizzlies are more aggressive and polar bears are likely to yield to them in confrontations. Polar bears will also scavenge at garbage dumps during ice-free periods. Polar bear mating takes place on

476-473: A combination of both. The inside of these shelters can be around 1.5 m (4.9 ft) wide with a ceiling height of 1.2 m (3.9 ft) while the entrance may be 2.1 m (6.9 ft) long and 1.2 m (3.9 ft) wide. The temperature of a den can be much higher than the outside. Females hibernate and give birth to their cubs in the dens. Hibernating bears fast and internally recycle bodily waste. Polar bears experience delayed implantation and

544-405: A day are more common during the former. The species is generally diurnal , being most active early in the day. Polar bears sleep close to eight hours a day on average. They will sleep in various positions, including curled up, sitting up, lying on one side, on the back with limbs spread, or on the belly with the rump elevated. On sea ice, polar bears snooze at pressure ridges where they dig on

612-502: A distinct head, and most of them without feet. They are principally distinguished by their tentacles (or feelers). By the Ancients they were not improperly called imperfect animals, as being destitute of ears, nose, head, eyes and legs; and are therefore totally distinct from Insects." Linnaeus divided the "Vermes" based upon the structure of the body, into the following orders and genera: The second volume, published in 1759, detailed

680-676: A female, a male will try to isolate and guard her. Courtship can be somewhat aggressive, and a male will pursue a female if she tries to run away. It can take days for the male to mate with the female which induces ovulation . After their first copulation, the couple bond. Undisturbed polar bear pairings typically last around two weeks during which they will sleep together and mate multiple times. Competition for mates can be intense and this has led to sexual selection for bigger males. Polar bear males often have scars from fighting. A male and female that have already bonded will flee together when another male arrives. A female mates with multiple males in

748-464: A long time without food, are tenacious of life, and have the power of reproducing parts which have been destroyed or lost; some undergo a metamorphosis; some cast (shed) their skin; some appear to live promiscuously on land or in the water, and some are torpid during the winter." Linnaeus divided the amphibians based upon the limb structures and the way they breathed, into the following orders and genera: Linnaeus described fish as: "Always inhabiting

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816-441: A marine environment, some taxonomists, such as Theodore Knottnerus-Meyer, have placed the polar bear in its own genus, Thalarctos . However Ursus is widely considered to be the valid genus for the species on the basis of the fossil record and the fact that it can breed with the brown bear. Different subspecies have been proposed including Ursus maritimus maritimus and U. m. marinus . However these are not supported and

884-494: A mid-sized seal out of the water or haul a beluga carcass for quite some distance. Polar bears only occasionally store food for later—burying it under snow—and only in the short term. Arctic foxes routinely follow polar bears and scavenge scraps from their kills. The bears usually tolerate them but will charge a fox that gets too close when they are feeding. Polar bears themselves will scavenge. Subadult bears will eat remains left behind by others. Females with cubs often abandon

952-533: A more efficient circulatory system . The polar bear's thicker coat is the result of more copies of genes involved in keratin -creating proteins. The polar bear is the largest living species of bear and land carnivore , though some brown bear subspecies like the Kodiak bear can rival it in size. Males are generally 200–250 cm (6.6–8.2 ft) long with a weight of 300–800 kg (660–1,760 lb). Females are smaller at 180–200 cm (5.9–6.6 ft) with

1020-418: A season and a single litter can have more than one father. When the mating season ends, the female will build up more fat reserves to sustain both herself and her young. Sometime between August and October, the female constructs and enters a maternity den for winter. Depending on the area, maternity dens can be found in sea ice just off the coastline or further inland and may be dug underneath snow, earth or

1088-723: A soft pulsing call, is made by mother bears presumably to keep in contact with their young. During the breeding season, adult males will chuff at potential mates. Unlike other animals where chuffing is passed through the nostrils, in polar bears it is emitted through a partially open mouth. Cubs will cry for attention and produce humming noises while nursing. Teeth chops, jaw pops, blows, huffs, moans, growls and roars are heard in more hostile encounters. A polar bear visually communicates with its eyes, ears, nose and lips. Chemical communication can also be important: bears secrete their scent from their foot pads into their tracks, allowing individuals to keep track of one another. The polar bear

1156-452: A time and travel an average of 154.2 km (95.8 mi). They can dive for as long as three minutes. When swimming, the broad front paws do the paddling, while the hind legs play a role in steering and diving. Most polar bears are active year-round. Hibernation occurs only among pregnant females. Non-hibernating bears typically have a normal 24-hour cycle even during days of all darkness or all sunlight , though cycles less than

1224-467: A weight of 150–300 kg (330–660 lb). Sexual dimorphism in the species is particularly high compared with most other mammals. Male polar bears also have proportionally larger heads than females. The weight of polar bears fluctuates during the year, as they can bulk up on fat and increase their mass by 50 percent. A fattened, pregnant female can weigh as much as 500 kg (1,100 lb). Adults may stand 130–160 cm (4.3–5.2 ft) tall at

1292-425: A weight of around 600 g (21 oz). Their eyes remain closed for a month. The mother's fatty milk fuels their growth, and the cubs are kept warm both by the mother's body heat and the den. The mother emerges from the den between late February and early April, and her cubs are well-developed and capable of walking with her. At this time they weigh 10–15 kilograms (22–33 lb). A polar bear family stays near

1360-534: A wider frequency range than expected given that their prey mostly makes low-frequency sounds. The nasal concha creates a large surface area, so more warm air can move through the nasal passages. Their olfactory system is also large and adapted for smelling prey over vast distances. The animal has reniculate kidneys which filter out the salt in their food. Polar bears inhabit the Arctic and adjacent areas. Their range includes Greenland, Canada, Alaska, Russia and

1428-608: A year, while drifting ice allows them to move further. Depending on ice conditions, a bear can travel an average of 12 km (7.5 mi) per day. These movements are powered by their energy-rich diet. Polar bears move by walking and galloping and do not trot . Walking bears tilt their front paws towards each other. They can run at estimated speeds of up to 40 km/h (25 mph) but typically move at around 5.5 km/h (3.4 mph). Polar bears are also capable swimmers and can swim at up to 6 km/h (3.7 mph). One study found they can swim for an average of 3.4 days at

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1496-486: Is Latin for ' sea bear ' . Carl Linnaeus classified the polar bear as a type of brown bear ( Ursus arctos ), labelling it as Ursus maritimus albus-major, articus in the 1758 edition of his work Systema Naturae . Constantine John Phipps formally described the polar bear as a distinct species, Ursus maritimus in 1774, following his 1773 voyage towards the North Pole . Because of its adaptations to

1564-620: Is a hypercarnivore , and the most carnivorous species of bear. It is an apex predator of the Arctic, preying on ice-living seals and consuming their energy-rich blubber . The most commonly taken species is the ringed seal , but they also prey on bearded seals and harp seals . Ringed seals are ideal prey as they are abundant and small enough to be overpowered by even small bears. Bearded seal adults are larger and are more likely to break free from an attacking bear, hence adult male bears are more successful in hunting them. Less common prey are hooded seals , spotted seals , ribbon seals and

1632-500: Is a 130,000- to 110,000-year-old jaw bone, found on Prince Charles Foreland , Norway, in 2004. Scientists in the 20th century surmised that polar bears directly descended from a population of brown bears, possibly in eastern Siberia or Alaska . Mitochondrial DNA studies in the 1990s and 2000s supported the status of the polar bear as a derivative of the brown bear, finding that some brown bear populations were more closely related to polar bears than to other brown bears, particularly

1700-438: Is more slender than the brown bear, with a narrower skull, longer neck and lower shoulder hump. Its teeth are sharper and more adapted to cutting meat. The paws are large and allow the bear to walk on ice and paddle in the water. Polar bears are both terrestrial and pagophilic (ice-living) and are considered marine mammals because of their dependence on marine ecosystems . They prefer the annual sea ice but live on land when

1768-1086: Is one of eight extant species in the bear family, Ursidae, and of six extant species in the subfamily Ursinae . Giant panda ( Ailuropoda melanoleuca ) [REDACTED] Spectacled bear ( Tremarctos ornatus ) [REDACTED] Sloth bear ( Melursus ursinus ) [REDACTED] Sun bear ( Helarctos malayanus ) [REDACTED] Asian black bear ( Ursus thibetanus ) [REDACTED] American black bear ( Ursus americanus ) [REDACTED] Polar bear ( Ursus maritimus ) [REDACTED] Brown bear ( Ursus arctos ) [REDACTED] Giant panda ( Ailuropoda melanoleuca ) [REDACTED] Spectacled bear ( Tremarctos ornatus ) [REDACTED] Sloth bear ( Melursus ursinus ) [REDACTED] Sun bear ( Helarctos malayanus ) [REDACTED] Asian black bear ( Ursus thibetanus ) [REDACTED] American black bear ( Ursus americanus ) [REDACTED] Polar bear ( Ursus maritimus ) [REDACTED] Brown bear ( Ursus arctos ) [REDACTED] Fossils of polar bears are uncommon. The oldest known fossil

1836-459: Is the primary hunting method from winter to early spring. Bears hunt walrus groups by provoking them into stampeding and then look for young that have been crushed or separated from their mothers during the turmoil. There are reports of bears trying to kill or injure walruses by throwing rocks and pieces of ice on them. Belugas and narwhals are vulnerable to bear attacks when they are stranded in shallow water or stuck in isolated breathing holes in

1904-403: Is thought to signal their fitness to females. The outer surface of the hairs has a scaly appearance, and the guard hairs are hollow, which allows the animals to trap heat and float in the water. The transparent guard hairs forward scatter ultraviolet light between the underfur and the skin, leading to a cycle of absorption and re-emission, keeping them warm. The fur appears white because of

1972-465: Is too specialized for animal matter, though they have been recorded eating berries, moss, grass and seaweed . In their southern range, especially near Hudson Bay and James Bay, polar bears endure all summer without sea ice to hunt from and must subsist more on terrestrial foods. Fat reserves allow polar bears to survive for months without eating. Cannibalism is known to occur in the species. Polar bears hunt their prey in several different ways. When

2040-473: The ABC Islands bears of Southeast Alaska . A 2010 study estimated that the polar bear lineage split from other brown bears around 150,000 years ago. More extensive genetic studies have refuted the idea that polar bears are directly descended from brown bears and found that the two species are separate sister lineages . The genetic similarities between polar bears and some brown bears were found to be

2108-411: The Arctic and nearby areas. It is closely related to the brown bear , and the two species can interbreed . The polar bear is the largest extant species of bear and land carnivore , with adult males weighing 300–800 kg (660–1,760 lb). The species is sexually dimorphic , as adult females are much smaller. The polar bear is white- or yellowish-furred with black skin and a thick layer of fat. It

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2176-542: The Russian Far East ) and Eastern Basin (Greenland east to Siberia). The polar bear is dependent enough on the ocean to be considered a marine mammal . It is pagophilic and mainly inhabits annual sea ice covering continental shelves and between islands of archipelagos . These areas, known as the "Arctic Ring of Life", have high biological productivity . The species tends to frequent areas where sea ice meets water, such as polynyas and leads , to hunt

2244-705: The Svalbard Archipelago of Norway. Polar bears have been recorded as close as 25 km (16 mi) from the North Pole . The southern limits of their range include James Bay and Newfoundland and Labrador in Canada and St. Matthew Island and the Pribilof Islands of Alaska. They are not permanent residents of Iceland but have been recorded visiting there if they can reach it via sea ice. As there has been minimal human encroachment on

2312-442: The backscatter of incident light and the absence of pigment. Polar bears gain a yellowish colouration as they are exposed more to the sun. This is reversed after they moult . It can also be grayish or brownish. Their light fur provides camouflage in their snowy environment. After emerging from the water, the bear can easily shake itself dry before freezing since the hairs are resistant to tangling when wet. The skin, including

2380-475: The seals that make up most of its diet. Polar bears travel in response to changes in ice cover throughout the year. They are forced onto land in summer when the sea ice disappears. Terrestrial habitats used by polar bears include forests, mountains, rocky areas, lakeshores and creeks. In the Chukchi and Beaufort seas, where the sea ice breaks off and floats north during the summer, polar bears generally stay on

2448-450: The 10th edition is Carl Alexander Clerck 's Svenska Spindlar or Aranei Suecici , which was published in 1757, but is also to be treated as if published on January 1, 1758. During Linnaeus' lifetime, Systema Naturae was under continuous revision. Progress was incorporated into new and ever-expanding editions; for example, in his 1st edition (1735), whales and manatees were originally classified as species of fish (as

2516-447: The animal kingdom was the 10th edition of Systema Naturae . The International Commission on Zoological Nomenclature therefore chose 1 January 1758 as the "starting point" for zoological nomenclature and asserted that the 10th edition of Systema Naturae was to be treated as if published on that date. Names published before that date are unavailable, even if they would otherwise satisfy the rules. The only work which takes priority over

2584-479: The application of their different perceptions. They all originate from an egg. Their external and internal structure; their comparative anatomy, habits, instincts, and various relations to each other, are detailed in authors who professedly treat on their subjects." The list has been broken down into the original six classes Linnaeus described for animals; Mammalia , Aves , Amphibia , Pisces , Insecta , and Vermes . These classes were ultimately created by studying

2652-608: The bears' remote habitat, they can still be found in much of their original range, more of it than any other large land carnivore. Polar bears have been divided into at least 18 subpopulations labelled East Greenland (ES), Barents Sea (BS), Kara Sea (KS), Laptev Sea (LVS), Chukchi Sea (CS), northern and southern Beaufort Sea (SBS and NBS), Viscount Melville (VM), M'Clintock Channel (MC), Gulf of Boothia (GB), Lancaster Sound (LS), Norwegian Bay (NB), Kane Basin (KB), Baffin Bay (BB), Davis Strait (DS), Foxe Basin (FB) and

2720-620: The birds based upon the characters of the bill and feet, into the following 6 orders and 63 genera: Linnaeus described his "Amphibia" (comprising reptiles and amphibians ) as: "Animals that are distinguished by a body cold and generally naked; stern and expressive countenance; harsh voice; mostly lurid color; filthy odor; a few are furnished with a horrid poison; all have cartilaginous bones, slow circulation, exquisite sight and hearing, large pulmonary vessels, lobate liver, oblong thick stomach, and cystic, hepatic, and pancreatic ducts: they are deficient in diaphragm, do not transpire (sweat), can live

2788-558: The breeding season, male bears guard females and defend them from rivals. Mothers give birth to cubs in maternity dens during the winter. Young stay with their mother for up to two and a half years. The polar bear is considered a vulnerable species by the International Union for Conservation of Nature (IUCN) with an estimated total population of 22,000 to 31,000 individuals. Its biggest threats are climate change , pollution and energy development. Climate change has caused

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2856-619: The breeding season. They have been recorded forming stable "alliances", travelling, resting and playing together. A dominance hierarchy exists among polar bears with the largest mature males ranking at the top. Adult females outrank subadults and adolescents and younger males outrank females of the same age. In addition, cubs with their mothers outrank those on their own. Females with dependent offspring tend to stay away from males, but are sometimes associated with other female–offspring units, creating "composite families". Polar bears are generally quiet but can produce various sounds. Chuffing ,

2924-402: The den for roughly two weeks; during this time the cubs will move and play around while the mother mostly rests. They eventually head out on the sea ice. 10th edition of Systema Naturae Before 1758, most biological catalogues had used polynomial names for the taxa included, including earlier editions of Systema Naturae . The first work to consistently apply binomial nomenclature across

2992-418: The fertilized embryo does not start development until the fall, between mid-September and mid-October. With delayed implantation, gestation in the species lasts seven to nine months but actual pregnancy is only two months. Mother polar bears typically give birth to two cubs per litter. As with other bear species, newborn polar bears are tiny and altricial . The newborns have woolly hair and pink skin, with

3060-475: The fishes based upon the position of the ventral and pectoral fins, into the following orders and genera: Linnaeus described his "Insecta" (comprising all arthropods , including insects , crustaceans , arachnids and others) as: "A very numerous and various class consisting of small animals, breathing through lateral spiracles, armed on all sides with a bony skin, or covered with hair; furnished with many feet, and moveable antennae (or horns), which project from

3128-405: The head, and are the probable instruments of sensation." Linnaeus divided the insects based upon the form of the wings, into the following orders and genera: Linnaeus described his "Vermes" as: "Animals of slow motion, soft substance, able to increase their bulk and restore parts which have been destroyed, extremely tenacious of life, and the inhabitants of moist places. Many of them are without

3196-461: The ice and then pokes its head in to catch the pup before it can escape. A ringed seal's lair can be more than 1 m (3.3 ft) below the surface of the ice and thus more massive bears are better equipped for breaking in. Some bears may simply stay still near a breathing hole or other spot near the water and wait for prey to come by. This can last hours and when a seal surfaces the bear will try to pull it out with its paws and claws. This tactic

3264-521: The ice melts in the summer. They are mostly carnivorous and specialized for preying on seals , particularly ringed seals . Such prey is typically taken by ambush; the bear may stalk its prey on the ice or in the water, but also will stay at a breathing hole or ice edge to wait for prey to swim by. The bear primarily feeds on the seal's energy-rich blubber . Other prey include walruses , beluga whales and some terrestrial animals. Polar bears are usually solitary but can be found in groups when on land. During

3332-463: The ice, though a large portion of the population (15–40%) has been observed spending all summer on land since the 1980s. Some areas have thick multiyear ice that does not completely melt and the bears can stay on all year, though this type of ice has fewer seals and allows for less productivity in the water. Polar bears may travel areas as small as 3,500 km (1,400 sq mi) to as large as 38,000 km (15,000 sq mi) in

3400-399: The ice. When stalking reindeer, polar bears will hide in vegetation before an ambush. On some occasions, bears may try to catch prey in open water, swimming underneath a seal or aquatic bird . Seals in particular, however, are more agile than bears in the water. Polar bears rely on raw power when trying to kill their prey, and will employ bites and paw swipes. They have the strength to pull

3468-461: The internal anatomy, as seen in his key: By current standards Pisces and Vermes are informal groupings, Insecta also contained arachnids and crustaceans , and one order of Amphibia comprised sharks , lampreys , and sturgeons . Linnaeus described mammals as: "Animals that suckle their young by means of lactiferous teats. In external and internal structure they resemble man: most of them are quadrupeds; and with man, their natural enemy, inhabit

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3536-810: The kingdom Plantae, in which Linnaeus included true plants , as well as fungi , algae and lichens . In addition to repeating the species he had previously listed in his Species Plantarum (1753), and those published in the intervening period, Linnaeus described several hundred new plant species. The species from Species Plantarum were numbered sequentially, while the new species were labelled with letters. Many were sent to Linnaeus by his correspondents overseas, including Johannes Burman and David de Gorter in South Africa , Patrick Browne , Philip Miller and John Ellis in America, Jean-François Séguier , Carlo Allioni and Casimir Christoph Schmidel in

3604-478: The more temperate-living harbour seals . Polar bears, mostly adult males, will occasionally hunt walruses both on land and ice. They mainly target young walruses, as adults, with their thick skin and long tusks, are too large and formidable. Besides seals, bears will prey on cetacean species such as beluga whales and narwhals , as well as reindeer , birds and their eggs, fish and marine invertebrates . They rarely eat plant material as their digestive system

3672-417: The nose and lips, is black and absorbs heat. Polar bears have a 5–10 cm (2.0–3.9 in) thick layer of fat underneath the skin, which provides both warmth and energy. Polar bears maintain their core body temperature at about 36.9 °C (98 °F). Overheating is countered by a layer of highly vascularized striated muscle tissue and finely controlled blood vessels. Bears also cool off by entering

3740-526: The polar bear does not have a particularly strong bite. Polar bears have large paws, with the front paws being broader than the back. The feet are hairier than in other bear species, providing warmth and friction when stepping on snow and sea ice. The claws are small but sharp and hooked and are used both to snatch prey and climb onto ice. The coat consists of dense underfur around 5 cm (2.0 in) long and guard hairs around 15 cm (5.9 in) long. Males have long hairs on their forelegs, which

3808-413: The polar bear is considered to be monotypic . One possible fossil subspecies, U. m. tyrannus , was posited in 1964 by Björn Kurtén , who reconstructed the subspecies from a single fragment of an ulna which was approximately 20 percent larger than expected for a polar bear. However, re-evaluation in the 21st century has indicated that the fragment likely comes from a giant brown bear. The polar bear

3876-525: The result of interbreeding. A 2012 study estimated the split between polar and brown bears as occurring around 600,000 years ago. A 2022 study estimated the divergence as occurring even earlier at over one million years ago. Glaciation events over hundreds of thousands of years led to both the origin of polar bears and their subsequent interactions and hybridizations with brown bears. Studies in 2011 and 2012 concluded that gene flow went from brown bears to polar bears during hybridization. In particular,

3944-424: The sea ice and during spring, mostly between March and May. Males search for females in estrus and often travel in twisting paths which reduces the chances of them encountering other males while still allowing them to find females. The movements of females remain linear and they travel more widely. The mating system can be labelled as female-defence polygyny , serial monogamy or promiscuity . Upon finding

4012-463: The seal or swimming towards a seal on an ice floe. The polar bear can stay underwater with its nose exposed. When it gets close enough, the animal lunges from the water to attack. During a limited time in spring, polar bears will search for ringed seal pups in their birth lairs underneath the ice. Once a bear catches the scent of a hiding pup and pinpoints its location, it approaches the den quietly to not alert it. It uses its front feet to smash through

4080-670: The sheltered side and lie down. After a snowstorm, a bear may rest under the snow for hours or days. On land, the bears may dig a resting spot on gravel or sand beaches. They will also sleep on rocky outcrops. In mountainous areas on the coast, mothers and subadults will sleep on slopes where they can better spot another bear coming. Adult males are less at risk from other bears and can sleep nearly anywhere. Polar bears are typically solitary, aside from mothers with cubs and mating pairs. On land, they are found closer together and gather around food resources. Adult males, in particular, are more tolerant of each other in land environments and outside

4148-418: The shoulder. The tail is 76–126 mm (3.0–5.0 in) long. 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. Compared with the brown bear, this species has a more slender build, with a narrower, flatter and smaller skull, a longer neck, and a lower shoulder hump. The snout profile is curved, resembling

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4216-690: The surface of the Earth. The largest, though fewest in number, inhabit the ocean." Linnaeus divided the mammals based upon the number, situation, and structure of their teeth, into the following orders and genera: Linnaeus described birds as: "A beautiful and cheerful portion of created nature consisting of animals having a body covered with feathers and down; protracted and naked jaws (the beak), two wings formed for flight, and two feet. They are areal, vocal, swift and light, and destitute of external ears, lips, teeth, scrotum, womb, bladder, epiglottis, corpus callosum and its arch, and diaphragm." Linnaeus divided

4284-556: The water. The eyes of a polar bear are close to the top of the head, which may allow them to stay out of the water when the animal is swimming at the surface. They are relatively small, which may be an adaption against blowing snow and snow blindness . Polar bears are dichromats , and lack the cone cells for seeing medium, mainly green, wavelengths. They have many rod cells , which allow them to see at night. The ears are small, allowing them to retain heat and not get frostbitten . They can hear best at frequencies of 11.2–22.5 kHz,

4352-502: The waters; are swift in their motion and voracious in their appetites. They breathe by means of gills, which are generally united by a bony arch; swim by means of radiate fins, and are mostly covered over with cartilaginous scales. Besides the parts they have in common with other animals, they are furnished with a nictitant membrane, and most of them with a swim-bladder, by the contraction or dilatation of which, they can raise or sink themselves in their element at pleasure." Linnaeus divided

4420-587: The western and southern Hudson Bay (WHB and SHB) populations. Bears in and around the Queen Elizabeth Islands have been proposed as a subpopulation but this is not universally accepted. A 2022 study has suggested that the bears in southeast Greenland should be considered a different subpopulation based on their geographic isolation and genetics. Polar bear populations can also be divided into four gene clusters : Southern Canadian, Canadian Archipelago , Western Basin (northwestern Canada west to

4488-493: The wild. Analysis of the number of variations of gene copies in polar bears compared with brown bears and American black bears shows distinct adaptions. Polar bears have a less diverse array of olfactory receptor genes, a result of there being fewer odours in their Arctic habitat. With its carnivorous, high-fat diet the species has fewer copies of the gene involved in making amylase , an enzyme that breaks down starch , and more selection for genes for fatty acid breakdown and

4556-835: Was given its common name by Thomas Pennant in A Synopsis of Quadrupeds (1771). It was known as the "white bear" in Europe between the 13th and 18th centuries, as well as "ice bear", "sea bear" and " Greenland bear". The Norse referred to it as isbjørn ' ice bear ' and hvitebjørn ' white bear ' . The bear is called nanook by the Inuit . The Netsilik cultures additionally have different names for bears based on certain factors, such as sex and age: these include adult males ( anguraq ), single adult females ( tattaq ), gestating females ( arnaluk ), newborns ( hagliaqtug ), large adolescents ( namiaq ) and dormant bears ( apitiliit ). The scientific name Ursus maritimus

4624-426: Was thought to be the case then). In the 10th edition, they were both moved into the mammal class. The animal kingdom (as described by Linnaeus): "Animals enjoy sensation by means of a living organization, animated by a medullary substance; perception by nerves; and motion by the exertion of the will. They have members for the different purposes of life; organs for their different senses; and faculties (or powers) for

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