What’s a Polar Bear?
The Polar Bear is easily recognizable from the distinctive white color of its fur. In fact the hairs appear to be white but are translucent and transmit light down to the skin. Below these hairs are “underhairs” of orange or yellow. Like a giant solar panel, the skin of the bear is black to draw every bit of possible heat from the sunlight. The neck is longer than other species of bears and the head is elongated, but the ears are relatively small. The front paws are very large with a small amount of webbing between the toes, which makes it a powerful swimmer. The soles of the feet have small “suction cups” to make them less likely to slip on the ice. The conditions of the polar north are harsh. Temperatures consistantly stay below freezing. In order to survive, the Polar Bear has to be an expert survivalist, able to cope with the grueling conditions of his environment.
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How big is a Polar Bear?
The Polar Bear is the largest land carnivore (meat eater) alive in the world today. Adult bears weight from 880 to 1320 lbs, and occasionally exceed 1,700 lbs. Females are about 1/2 the size of males and normally weigh 440 to 660 lbs. Immediately before entering the maternity den in the fall, the weight of a pregnant female can exceed 1100 lbs because of the enormous amount of stored fat. Males measure 8 to 9 ft in length and females 6 to 7 ft.
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Where do they live?
The preferred habitat of Polar Bears is the polar regions of the Northern Hemisphere. They usually stay where the northern seas meet the shoreline. Although they have been recorded in the heavy multi-year ice of the central polar basin, they rarely enter this zone because it is unproductive biologically and there is little to eat. In areas such as the Hudson Bay, where the ice melts completely for a few months in the late summer and fall, bears spend the summers on land, resting to conserve energy and waiting for freeze-up.
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What do they eat?
Polar Bears are the most carnivorous of all the bears and live almost entirely on ring seals, and to a lesser degree, on bearded seals. They are known to prey on young walruses and occasionally even capture narwhals. Wind and currents create cracks in the ice that concentrate the seals they hunt. They are mighty hunters and very patient. They will sit by a seal blowhole for hours, waiting, until the animal surfaces. When it does, one powerful blow from the fore paw, and it is all over. It’s stomach capacity is very large and enables it to take advantage of large meals when it can.
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What about cubs?
Polar bears mate from late March to late May. Implantation of the fertilized egg is delayed until September or early October and the cubs are born between late November and early January. About 70% of the liters consist of 2 cubs. Litters of 4 or more are rare and and it would be unlikely for all of the cubs to survive. Cubs are tiny, blind, and hairless. At birth they weigh 21 to 25 ounces. Due to the mothers fat enriched milk (40% fat), they weigh 20 to 30 pounds at 3 or 4 months and are able to follow their mother when she leaves the den. Cubs remain with their mothers until they are 2 1/2 years old, so the most often females breed is once every 3 years. This means that only a third of them are available in each breeding season. The result is intense competition between males for mates, which is probably one of the reasons why males are twice the size of females.
What about hibernation?
Males do not generally hibernate, but remain active for most of the year. The pregnant females are the exception to this, however. They go through a denning and hibernation period, just like that of the Black, Brown and other bears.
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How long do they live?
Probably 20 to 25 years. They have no natural predators so the primary causes of death are disease, injury and starvation. Due to the harsh environment in which it lives, the Polar Bear must learn very quickly to provide for itself or it will die shortly after leaving it’s mother.
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