What happens to dead polar bears corpses?
There are other carnivores that exist in the same habitat, arctic foxes are one example, I am not sure whether they scavenge, but if they do then they could remove parts of polar bear corpses, as well as Inuits as the other answers say. Also there are some bacteria that exist in the arctic these will decay the polar bears flesh. As the amount of Ice in the Arctic changes with the seasons, it is probably that many of the corpses end up in the sea when the Ice melts, in this case they will be eaten by fish and other marine life and bacteria. It is possible that there are some polar bear corpses frozen in the Ice although I doubt that that is where the majority of them end up.