When polar bears hunt, they crouch down by a hole in the ice and wait for a seal to pop up. They keep one paw over their nose so that they blend in, because they've got those black noses. They'd blend in perfectly if not for the nose. So the question is, how do they know their noses are black? From looking at other polar bears? Do they see their reflections in the water and think, "I'd be invisible if not for that." That seems like a lot of thinking for a bear.