With a wildlife guide, I stepped on a journey to find one of the rarest creatures in the world—the spirit bear, a walking contradiction—a white black bear. Neither albino nor polar bear, the spirit bear (also known as the Kermode bear[1]) is a white variant of the North American black bear, and it’s found almost exclusively here in the Great Bear Rainforest. At 25,000 square miles—one and a half times as big as Switzerland—the region runs 250 miles down Canada’s western coast. It also consists of a vast network of mist-shrouded fjords, densely forested islands, and glacier-capped mountains. Grizzlies, black bears, wolves, wolverines, humpback whales, and orcas thrive along this coast. It’s a spooky[2], wild, mysterious place: there are wolves here that fish. Deer that swim. Western red cedar trees that have stood a thousand years. And a black bear that is white.

At first we did not see any spirit bear. My guide Robinson scanned for movement. No bears. But then he spotted a tuft of white fur snagged on an alder branch. “They’re around here, for sure,” he said. He pointed to the chewed bark. “They like to stand and bite the tree just to say to other bears, I’m here using this river.” An hour passed. Robinson and I waited patiently on top of a moss-patched boulder. Then he heard a rustling in the bush. “There he is,” he said.

A white bear stepped out of the tree cover onto a streamside rock. Set against the dark rain forest, the bear’s fur appears shabbily radiant. Not pure white, exactly. More like a vanilla-colored carpet in need of a steam cleaning. The bear swung its head from side to side, peering into an eddy for salmon. Before it can lunge for[3] one, a black bear suddenly comes out of the forest and runs the white bear off its perch—though “runs” might be a bit strong. Everything the bears do seems to unfold in slow motion, as if they’re trying to conserve every last calorie for the coming winter. The white bear lumbers[4] into a thicket and disappears.

Robinson watches. He’s spent 15 years among the spirit bears. Still, he’s transfixed. “This particular white bear is very submissive,” he says. “Sometimes that gets to[5] me. I’m protective. I once saw an old white bear attacked by a younger black bear. I was about to jump in and pepper spray the black one. The instinct was strong in me. But then the white one reared up and threw him off.” Robinson smiles.

Robinson isn’t alone. That same protective instinct runs strong throughout the Great Bear Rainforest. It’s one of the factors that have kept the spirit bear alive. “Our people never hunted the white bear,” said a native clan matriarch. Bear meat was rarely a main food, though they went after black bear in greater numbers when European merchants established the British Columbian fur trade in the late 18th century. Even in those days, taking a white bear was taboo, a tradition that has continued through many generations. “We never even spoke of the spirit bear at the dinner table,” she said.

Scientists know how black bears are born white. They’re just not sure why. The phenomenon, known as Kermodism, is triggered by a recessive mutation at the MC1R gene, the same gene associated with red hair and fair skin in humans.[6] To be born white, a bear must inherit the mutation from both parents. The parents themselves don’t have to be white. They just need to carry the recessive mutation. So it’s not uncommon for white bears to be born to black parents.

White fur happens in only one of every 40 to 100 black bears on the British Columbia mainland coast, but the trait is especially distinct on certain islands in the Great Bear Rainforest. For example, on Princess Royal Island, one in ten black bears is white, and on Gribbell Island, directly north of Princess Royal, it’s one in three.

It’s unclear how the trait arose. One theory was the “glacial bear” hypothesis that the spirit bear represented a remnant adaptation from the last great ice age, which ended here 11,000 years ago. At that time most of modern-day British Columbia was still icebound, and a white coat may have offered camouflage. But the “glacial bear” theory raised a question: Why didn’t the white fur trait die out when the glaciers receded?

Researchers have recently proved that the spirit bear’s white coat gives it an advantage when fishing. Although white and black bears tend to have the same success rate after dark, there is a difference during the daytime. White bears catch salmon in one-third of their attempts. Black individuals are successful only one-quarter of the time. “The salmon are less concerned about a white object as seen from below the surface,” a scientist speculates. That may answer part of the question about why the white-fur trait continues to flourish today. If salmon are a coastal bear’s primary fat and protein source, a successful female can feast on salmon to store more fat for winter, potentially increasing the number of cubs she can produce.

As the rain continued to fall on Princess Royal Island, we watched the spirit bear feed on a bounty of salmon. When the pickings are good, bears can turn finicky. Some eat only the fish head. Others may slit the belly and suck out the eggs. Some are gluttons. We observed the scene for hours, until daylight faded from the sky.