“To have a rare color … that’s not found anywhere on Earth—there’s a story there,” Lewis says.

In their latest research, Lewis and colleagues have offered new clues into why glacier bears are so unusual. The research also has revealed potential challenges to the bears’ future as temperatures rise due to global climate change.

The team identified 10 black bear populations in and around the national park, four of which contained glacier bears. The glacier bears were separated from each other by wide fjords, glacier-capped mountains, and barren ice fields. Yakutak glacier bears, for instance, live more than 60 miles from their closest glacier bear neighbors, the Glacier Bay West bears.

“Some bears will cross that ice field, some bears will swim