The Life Cycle of the Polar Bear
The life cycle of the polar bear is complicated. One-third of the female population of polar bears are unavailable every breeding season because female polar bears care for their young until they are two-and-a-half years old Remarkably breeding occurs months before gestation begins. Polar bears are a marvel of adaptation to their Arctic environment.
Late March through Late May
Polar bears breed during the Arctic spring from late March
through late May. Male polar bears track breeding females across the frozen landscape. Researchers have recorded male polar bears tracking a female for as many as 95 kilometers (60 miles). Males will spar with each other should they find the same female at the end of the trail. The winner - the dominant male - will spend between seven and 14 days with the female mating.
During the Arctic spring, females feed heavily, doubling their body weight, the resulting weight gain can be as much as 200 kilos (440 pounds). That said, polar bears may fast for up to eight months during food shortages.
June to mid September
During the summer months
, polar bears eat little, because their primary source of food, ring seals, is not readily available. Sea ice formation is essential for both polar bears and ring seals. Polar bears conserve their energy until they can hunt again.
Polar bear cubs learn to hunt by copying the actions of their mothers. It can take as long as two years, before they gain sufficient hunting skills to survive.
Mid September to mid October
The fertilized eggs remain suspended within the female's body until August or September. If the female does not gain sufficient weight, the eggs will not implant.
November through December
Female polar bears enter their birthing dens to hibernate and give birth to cubs so small that you could hold them in the palms of your hand. Two-thirds of the litters born to polar bears are twins. Single cubs and triplets are known.
January through mid March
Female polar bears that gave birth to cubs between October and November are hibernating in the den while their cubs nurse. The family emerges from the den in late March or April, remaining near the den for about 12 days. During this period, the cubs develop their walking muscles.