The white coat of the Kermode bear traces to a single-nucleotide change in the MC1R gene, which controls the switch between dark eumelanin and lighter pigment in mammal hair. Bears carrying two copies of the recessive variant grow a cream to pale-yellow coat. Their eyes, nose and skin are normally pigmented, which is what separates them from true albinos.
The variant is concentrated rather than widespread. It reaches its highest frequency on a handful of islands in the Great Bear Rainforest of coastal British Columbia, where roughly one in ten bears is white on some islands, and the proportion drops sharply on the adjacent mainland. Two dark-coated parents can produce a white cub if both carry a single copy.
Black bear colour varies widely elsewhere for reasons unrelated to this gene. Cinnamon and blonde animals are common in western North America, and a blue-grey glacier bear form occurs in southeast Alaska. One tested hypothesis is that white coats improve fishing success by being less conspicuous to salmon from below; support for it exists but the size of the advantage, and whether it is enough to maintain the variant, remains disputed.