what is its food?
Its diet primarily consists of ringed and bearded seals.
Polar bear
The polar bear is the most carnivorous member of the bear family, and throughout most of its range, its diet primarily consists of ringed ("Pusa hispida") and bearded seals ("Erignathus barbatus"). 
where did the polar bear live with her family Within the Arctic Circle, encompassing the Arctic Ocean, its surrounding seas and surrounding land masses.
wiki:25639072
Polar bear [SEP] Hunting and diet
The polar bear is the most carnivorous member of the bear family, and throughout most of its range, its diet primarily consists of ringed ("Pusa hispida") and bearded seals ("Erignathus barbatus"). The Arctic is home to millions of seals, which become prey when they surface in holes in the ice in order to breathe, or when they haul out on the ice to rest. Polar bears hunt primarily at the interface between ice, water, and air; they only rarely catch seals on land or in open water. The polar bear's most common hunting method is called "still-hunting": the bear uses its excellent sense of smell to locate a seal breathing hole, and crouches nearby in silence for a seal to appear.