Different yet the same. Under the geno and phenotype, they are different bears. (Genotype is the makeup of the genes, phenotype is the actual physical description) This is why the species (polar bears usrus maritimus or sea bear) (brown bear ursus arctos or horribilus, depending on region) are different... though the same. So under the actual words which describe the bear they are different, but their genetic make up makes it so they are reproductively the same species. Turns out science isn't always exact :-D :-D
The polar bear is actually classified as a marine mammal, even though its closest relatives (the brown being the closest) are not. They even have webbed feet (not like fins, but slightly)