What Arctic animal that would be eaten by a polar bear and it eat moss?

This is just a guess, but I find it fairly logical...

I'd say that polar bears would NOT eat moss in the winter time because in the winter, polar bears are out on the ICE, which is far away from much rock. It's also covered with snow, which would make it hard for moss to grow.

And, little heat escapes from the polar bear's body, and it IS possible for it to die from overheating. Strange, isn't it?