The polar bear (Ursus maritimus) is a hypercarnivorous bear whose native range encompasses the Arctic Ocean, its surrounding seas, and surrounding land masses. It is the largest surviving bear species and the largest surviving land carnivore. [6] [7] A boar (adult male) weighs approximately 350-700 kg (770-1,540 lb),[8] while a sow (adult female) is approximately half that size. Despite being the brown bear's sister species,[9] it has evolved to occupy a narrower ecological niche, with many body characteristics adapted for cold temperatures, moving across snow, ice, and open water, and hunting seals, which make up the majority of its diet. [10] Although most polar bears are born on land, they spend the majority of their time in the sea.