Anyone who has waited on the shore of Hudson Bay near Churchill, Manitoba, in late autumn may have watched a polar bear amble along the ice edge. The world holds a single species of polar bear, and in Canada it ranges across a vast sweep of the Arctic, from the coast of Manitoba in the south to the high islands of Nunavut in the far north. For countless generations the animal has provided northern peoples with food, warm hides, and material for tools. Today the polar bear is honoured as a national emblem and appears on the two-dollar coin, the "toonie." Yet behind this familiar figure lies a hunter whose whole body is shaped for survival on the sea ice.
Few large animals are so completely fitted for the cold. Beneath the polar bear's thick outer coat lies a dense underfur, and below the skin sits a layer of fat that can be more than ten centimetres deep. Together they hold in warmth even when the wind drops far below freezing. Its broad front paws, slightly webbed between the toes, act like paddles, so that a bear can swim steadily for many hours and cross open water dozens of kilometres wide. Its nostrils close tight when it dives, and small bumps on the soles of its feet grip the ice and keep it from slipping.
