The family life of polar bears

Polar bears are usually solitary animals but in southern areas of the Arctic they gather together on land during the ice-free season. Breeding pairs remain together for about a week then separate. The most constant social interaction occurs between mothers and cubs.

In the late autumn, pregnant females dig dens in deep snow drifts on land while the rest of the population remains active on the ice through the winter. In the Beaufort Sea, some polar bears dig maternity dens in snow drifts on multi-year ice floes, while in western and southern Hudson Bay cubs can be born in dens excavated in frozen peat banks. After about 2 months, the cubs are born in the den.

There are usually 2 cubs, each weighing only 600g (1.3lbs), about the size of a guinea pig. Cubs are nursed in the den on fat-rich milk until they weigh about 10kg (22lbs) and are large enough to venture onto the sea ice in March or April. In most areas,  they stay with their mother for about 2.5 years before striking out on their own.