Females den by digging into deep snow drifts, which provide protection and insulation from the Arctic elements. They give birth in winter, usually to twins. Young cubs live with their mothers for some 28 months to learn the survival skills of the far north. Females aggressively protect their young, but receive no help from their solitary male mates. In fact, male polar bears may even kill young of their species.
Four bear cubs climb up a tree for safety as an alpha male approaches them. Fearing for her cub's lives the mother bear urged them to scramble up the nearest tree trunk while she kept watch on the ground. The scene was captured by photographer Lauri Tammik in woods in north Finland.