Polar bear

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Taxonomy and Evolution:
– Carl Linnaeus classified the polar bear as a type of brown bear (Ursus arctos).
– Constantine John Phipps formally described the polar bear as a distinct species, Ursus maritimus.
– Genetic studies indicate that polar bears split from brown bears around 600,000 to over one million years ago.
– Glaciation events led to the origin of polar bears and hybridizations with brown bears.
– Fossils of polar bears are rare, with the oldest known fossil being a jaw bone dating back 130,000-110,000 years.

Physical Characteristics and Feeding Habits:
– The polar bear is the largest living bear species and land carnivore.
– Adult polar bears can weigh up to 500kg (1,100lb) and stand 130–160cm (4.3–5.2ft) tall.
Polar bears prey on animals smaller than them, specializing in seals like ringed seals.
– They have 34–42 teeth adapted for a carnivorous diet and a less strong bite force due to typical prey size.
– Large paws with sharp claws, dense fur, and a layer of fat aid in hunting and warmth.

Behavior and Habitat:
Polar bears are terrestrial and ice-living, considered marine mammals due to their dependence on marine ecosystems.
– They are mostly solitary but can be found in groups when on land and gather around food resources.
Polar bears inhabit the Arctic and adjacent areas like Greenland, Canada, Alaska, and Russia.
– They can travel long distances annually, run at speeds up to 40km/h (25mph), and swim at 6km/h (3.7mph).
Climate change, pollution, hunting, and human conflicts are major threats to polar bears’ habitat and survival.

Reproduction and Development:
Polar bear mating takes place on sea ice during spring, with females hibernating and giving birth to cubs in dens.
– Delayed implantation allows for a shorter actual pregnancy period, with mother bears typically giving birth to two cubs per litter.
– Cubs are kept warm by the mother’s body heat and the den, weaned between two and two-and-a-half years, and reach sexual maturity at around four to six years.
– Mortality factors include threats from wolves, adult males, starvation, injuries, and parasitic infections.
Conservation efforts are crucial to mitigate threats and ensure the survival of polar bear populations.

Conservation Status and Climate Change:
– The polar bear is considered a vulnerable species by the IUCN, with an estimated population of 22,000 to 31,000 individuals.
Climate change, pollution, and energy development are significant threats to polar bears, leading to habitat loss and reduced access to prey.
– Rising temperatures cause sea ice to melt earlier, affecting polar bears’ hunting and reproductive rates.
Conservation efforts focus on protecting habitats, reducing human-bear conflicts, and addressing climate change impacts to secure the future of polar bears.
– Studies predict a significant decline in polar bear numbers and regional extinctions if current trends in climate change and habitat loss continue.

Polar bear (Wikipedia)

The polar bear (Ursus maritimus) is a large bear native to the Arctic and nearby areas. It is closely related to the brown bear, and the two species can interbreed. The polar bear is the largest extant species of bear and land carnivore, with adult males weighing 300–800 kg (660–1,760 lb). The 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 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 bear
Temporal range: Pleistocene–recent
Female near Kaktovik, Barter Island, Alaska, United States
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Ursidae
Genus: Ursus
U. maritimus
Binomial name
Ursus maritimus
Phipps, 1774
Polar bear range

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

Polar bears are both terrestrial and pagophilic (ice-living) and are considered to be marine mammals due to their dependence on marine ecosystems. They prefer the annual sea ice but live on land when 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 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 to be 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 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.

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