Polar Bears
(Ursus maritimus)

Length: 8.25-11.5 feet
Height (on 4’s): 3.5 feet
Weight: 1,000 - 1,320
Life span: 25 years
Gestation: 220 days
Max. Speed: 25 mph

Physical Characteristics

The polar bears are direct descendants of the grizzly. They have smaller heads than other bears but have longer necks which is an adaptation for swimming. They have a short tail and short ears. Their canine teeth are longer and sharper than the grizzly’s because the polar bear is mostly carnivorous. Their fur has two layers: an undercoat with fine white hairs and a guard coat with hollow hairs, another adaptation for swimming. Their scientific name, “Ursus maritimus” is Latin for “sea bear”. And that it is - the polar bear can swim for 60 mph and can stay underwater for two minutes down 15 feet.

Habitat and Daily Life

The polar bears don’t really have territories like other bears would. They are mainly roamers and do not defend the areas that they live in. They may cover over 100,000 square miles in their life time. Polar bears are found in all polar regions in the northern hemisphere.

Hunting and Feeding

The diet of the polar bear is consisted of almost exclusively meat. Seals are their primary source of food and they may kill on every few days. They can, however, go for weeks without food due to their large stomach which can hold up to 150 pounds of food. During the summer when food begins to diminish, they eat anything possible including bird eggs, berries, rodents, and carrion as well. The polar bear will eat a human if one is near, but this is not a common occurrence.

Reproduction and Hibernation

Females reach sexual maturity at around five years of age, males at around eight. Mating occurs on the ice during March or July. After a gestation period of about 220 days, one two three cubs are born, twins being the most common. The only polar bears that hibernate are pregnant females. They prepare a den in a southern slope about ten or more feet deep in an oval chamber. The temperature may reach above freezing because of the good insulation. When the female is finished hibernation and she is ready to go look for food, the cubs will be able to follow her.

Status

Over hunting brought a huge decline in polar bears all throughout the northern hemisphere. In 1967 a conservation treaty was passed to save the bears. Today the population is relatively stable with a worldwide population of 20,000-40,000 bears. The largest population of polar bears resides in Canada with a population of about 15,000.