Mutant Polar Bears could be found in the arctic regions of the deathlands.
Ryan, separated from his companions, while in Alaska, encounters a huge mutant polar bear. He is forced to empty an entire fifty round magazine into the bear, killing it. He then feasts off the bear in order to try and stay alive. Not much is mentioned describing the bear, only that it is huge, had long tusks, and huge shaggy paws. (Red Holocaust)