What is the largest bear species?

The polar bear is the largest living bear species. Its scientific name is Ursus maritimus, meaning “sea bear,” a reference to its close dependence on Arctic sea ice and marine food sources. Adult males are substantially larger than females and can weigh several hundred kilograms.

Polar bears evolved from brown-bear ancestors and remain close relatives. The two species can interbreed, producing hybrids sometimes called pizzly or grolar bears. Even so, they are recognized as separate species with different body shapes and lifestyles. Polar bears have a longer neck, narrower skull and more streamlined form than brown bears, adaptations that help them swim and hunt seals.

Brown bears—and especially the Kodiak subspecies—can rival polar bears in size, which causes frequent confusion. However, polar bears are generally accepted as the largest extant bear species by average and maximum body mass. They are also considered the largest living land carnivores, although they spend much of their time on sea ice rather than solid land.