Grizzly bears, for example, are a subspecies of brown bear found in parts of North America. There are many different ...

While today’s polar bears are found exclusively in the Arctic, their ancestors likely migrated across Europe and the North Atlantic, following ice-covered coastlines. During the last Ice Age ...

In "Ends of the Earth," Neil Shubin travels north and south to explore the frontiers of polar science and history.

Why does the Arctic have polar bears and Antarctica penguins ... is the fact that fossils of possible ancestors of living species are often found in the same parts of the globe where their ...