A popular question: Who is the bigger bear; the Kodiak bear or the polar bear? In the comparison above you can see two prime males scaled to their maximum shoulder heights; the largest polar bears edge out the largest brown bears in that regard. In terms of weight itself the polar bear also has the edge over the brown bear and is rightfully accepted as the biggest bear roaming our earth producing several specimens outweighing the record brown bears of Alaska. Why does the polar bear get so big? The climate and its diet; he has to have a healthy fat layer over the course of the whole year and is a carnivoran without any excepetions; his access to fresh blubber and fats of marine prey items enables remarkable growth.