Female polar bears care for their young by feeding and protecting them from the time they are born until they are weaned at about 1 1/2 to 2 1/2 years of age. Males abandon females after mating and do not help to care for the cubs.
March through May is the polar bear breeding season. Males pick up the scent of females and track them across the ice. Often, several males battle for a female. The winner stays with the female for about a week. For the next four months, the female polar bear eats enough food to prepare for a long fast, often gaining more than 400 pounds and doubling her body weight. In the fall, she creates a den by burrowing into the snow or permafrost. Sometime between November and February, she gives birth, usually to two lightly furred blind cubs weighing 1 to 2 pounds each. She nurses them until early spring, when she breaks open the entrance, and they leave the den. After the cubs take a few weeks to learn to move about, the mother and cubs return to the ice floes so that she can hunt.
The female polar bear hunts for seals for herself, but though her cubs learn to hunt from her example, they continue to nurse for their nourishment. The female is not only affectionate but also protective. Dangers include wolves and polar bear males, who sometimes attack and eat the cubs. The mother abandons or drives away the cubs when they are weaned and she is ready to mate again.