* Size difference: Blue whales are incredibly large, reaching up to 100 feet in length and weighing up to 200 tons. Polar bears, while large for land predators, are dwarfed in comparison. Even a group of polar bears couldn't bring down such a massive creature.
* Habitat: Polar bears live in the Arctic, on sea ice and land. Blue whales live in the ocean, spending most of their time in open water. Their habitats rarely overlap.
* Diet: Polar bears primarily eat seals, which they hunt on the ice. Blue whales feed on krill and other small creatures in the ocean. They have different feeding strategies and prey.
While a polar bear might be able to scavenge a small piece of a blue whale carcass if one washed ashore, they are not capable of hunting or killing them.