It looked like we had the polar bear’s origin story nailed down. Genetic studies suggested that between 111 and 166 thousand years ago, a group of brown bears, possibly from Ireland, split off from their kin. In a blink of geological time, they adapted to the cold of the Arctic, and became the polar bears we know and worry about. Fossils supported this story: the oldest polar bear bone is between 110 and 130 thousand years old.

But according to Frank Hailer at the Biodiversity and Climate Research Centre in Frankfurt, this story is wrong in two important ways. First, the polar bear aren’t just a branch of the brown bear family tree. They’re a separate lineage in their