Which one would win a fight, a polar bear or a grizzly bear?
The grizzly bear is 55% larger than the polar bear. Between grizzlies and polar bears, if there was a fight and it relied on their physical differences alone—the grizzly bear would be more likely to emerge victorious.
However, this is not an accurate measure of how they would behave in the wild. For example, while a polar bear might think he can win a fight against a grizzly bear because of his size advantage, the grislier bears are smarter than many other types of species that live in colder climates (such as walruses) due to their greater need for social interaction amongst females with cubs.