To a Salmon’s Eye, Spirit Bears Have Natural Camouflage
Salmon are much more likely to avoid a black bear-shaped object than a white one. (Hakai Magazine)
In the Great Bear Rainforest, in coastal British Columbia, two large bears—one black, one white—wade into a stream. The white bear dips its snout and comes up with a wriggling salmon clutched between its jaws. The black bear does the same. But as time goes on, with the two bears snagging fish after fish, the white bear seems to be having an easier time. It turns out, it is—and there’s an intriguing reason why.
Spirit bears are black bears with a recessive genetic mutation that turns their regular charcoal-colored fur a ghostly white. Fewer than 200 of these unusual bears are estimated to live on British Columbia’s north and central coasts, where they have long held a special significance in coastal Indigenous cultures. According to one story from the Kitasoo/Xai’xais, the creator Raven made one out of every 10 bears white to remind people that the land had previously been covered by a glacier, and to appreciate the bounty the landscape offers today.
That ratio—about one out of 10—has fascinated scientists. Studies have shown that, in certain parts of British Columbia, from 10 to 30 percent of bears have this distinctive coloration—a rate that is far more frequent than what would be expected if the bears’ white fur was the result of random chance alone. It implies that the white bears may have some sort of evolutionary advantage over the black bears. A new study has teased apart what that advantage could be...