Where do polar bears live in the wild?

The Arctic, and only the Arctic. Penguins live in the southern hemisphere, so the two never meet outside a Christmas card - a mistake so common that the joke about polar bears not eating penguins because they cannot get the wrappers off relies on it.

A polar bear is not really a land animal. Its scientific name means sea bear, it is classified as a marine mammal, and it hunts almost exclusively from sea ice, waiting at the breathing holes seals must use. Take the ice away and the animal is not merely inconvenienced; it is separated from its only reliable food.

The insulation is strange in two ways. The fur is not white - each hair is a hollow transparent tube, and the animal looks white for the same reason snow does, by scattering light. Underneath, the skin is black. And bears in zoos in humid climates occasionally turn green, when algae take up residence inside those hollow hairs.