Learn about polar bears! Polar bears are the largest land carnivores in the world, rivaled only by the Kodiak brown bears of southwestern Alaska. Polar bears sit at the top of the food chain in the biologically rich Arctic. The most carnivorous of the bear species, polar bears feed primarily on the fat of ice-dependent seals. The remains of these seals provide food for many other Arctic wildlife species, giving polar bears a vital role in their ecosystem.