Polar Bears belong to the Ursidae family and they are mammals. They are found in both hemispheres and are carnivores in nature but sometimes they also consume fruits and leaves. Some varieties of bears consume bamboo shoots and this shoot is considered as 99% part of their diet, whereas some other varieties also consume termites and ants also.
The polar bear (Ursus maritimus) is a hypercarnivorous bear native to the Arctic Circle, which includes the Arctic Ocean, its adjacent seas, and adjacent land masses. It is the country's leading bear species and the world's largest ground carnivore.
A boar (adult male) averages 350–700 kg (1,540–1,540 lb), while a sow (adult female) is around half the size. While it is the brown bear's sister species, it has grown to inhabit a smaller ecological niche, with several body features adapted for cold environments, travelling around ice, snow, and open water, and hunting seals, which constitute the majority of its diet.
Despite the fact that the majority of polar bears are born on land, they spend the majority of their time on the sea ice. This reality is reflected in their scientific name, which means "maritime bear." Polar bears kill seals from the edge of the sea ice, and when there is no sea ice, they depend on fat reserves to survive. Polar bears are known as marine mammals because of their reliance on sea ice.
At present time there are only eight species of bear, they are:
Asian black bear – Ursus thibetanus
American black bear – Ursus americanus
Brown bear – Ursus arctos
Giant panda – Ailuropoda melanoleuca
Sloth bear – Melursus ursinus
Sun bear – Helarctos malayanus
Spectacled bear – Tremarctos ornatus
Polar bear – Ursus maritimus
Classification of Bear
The scientific name of the bear is Ursus.
Since it spends so much of the year at sea, the polar bear is classified as a marine mammal. It is, however, just one living marine mammal with strong, large limbs and toes which allow it to walk and run for kilometres on land. The annual sea ice that covers the waters from over continental shelf and the Arctic inter-island archipelagos has been its favored habitat.
In contrast to the shallow waters of the Arctic Region, these regions, known as the "Arctic ring of life," have quite a great biomass productivity. To kill the seals that constitute the majority of its diet, the polar bear prefers areas whereby sea ice reaches water, including polynyas and leads (temporary stretches of open water in Arctic ice).
Since freshwater has been either chained up in snow or salty in these areas, it is scarce. Polar bears can release water via the digestion of fats contained in seal blubber, so they prefer to be found near the polar ice pack's perimeter instead of being in the Polar Basin near the North Pole, whereby seal density becomes low.
Hunting and Diet
The polar bear has been the most carnivorous part of the bear family, and it eats mostly ringed (Pusa hispida) and bearded seals throughout its range (Erignathus barbatus). Hundreds of thousands of seals live in the Arctic, however when they surface in holes in the ice to breathe or drag out over the ice to relax, they become prey. Polar bears chase seals mainly at the ice-water-air interface; they only capture seals on land or in open water on rare occasions.
Still-hunting is the most popular polar bear targeting method: the bear utilizes its outstanding smell senses to find a seal breathing hole and crouches nearby in silence, waiting for a seal to appear. It's possible that the bear will lie in wait for some hours. The bear senses the seal's breath and reaches into the cavity with his forepaw, dragging it out onto the ice.
The seal is killed by the polar bear chewing its head and crushing its skull. When a polar bear spots a seal lying on the ice, it walks to within 90 metres of the seal and afterwards crouches. If the seal isn't paying attention, the bear creeps up to within 9 to 12 metres of the seal and then charges forward to strike. Raiding the birth lairs that female seals make in the snow is a third form of hunting.
Reproduction and Lifecycle
In April and May, as polar bears congregate in the appropriate seal hunting grounds, courtship and mating actually occur on the sea ice. After tracking down a breeding female for 100 kilometres (60 miles), a male can engage in brutal battles with several other males for mating rights, which often results in scars and broken teeth.
Polar bears possess a polygynous mating pattern in general, but recent genetic testing of mothers and cubs has shown cases of litters with separate fathers. For a whole week, partners remain together and mate constantly; the mating ritual causes the female to ovulate. The fertilised egg persists in a dormant state throughout August or September following mating. The pregnant woman consumes copious quantities of food over these four months, accumulating at least 200 kg (440 lb) and frequently more than double her body weight.
Important Facts About Bear
1. Lifespan of a bear is about 20 years.
2. Bears can run at a speed of 40km/hr.
3. Polar bears are considered as one of the heaviest bears with a weight of approx 450Kg.
4. Gestation period of bears is about 195 – 265 days.
5. During winter most of the bears undergo hibernation due to scarcity of food in the winter season. As during hibernation, most of the process gets lowered like heart rate, body temperature, metabolism, and respiration.
6. Giant panda bears mostly feed bamboo shoots.
7. Smallest species of bear is the Sun bear, having a weight of about 25kg.