Kermode Bears: Why These Black Bears Are Born White

Within the Great Bear Rainforest, in Canada, are many species of animals that thrive in this dense and lush environment. Perhaps the most highly esteemed of all is the Kermode Bear (otherwise known as the Spirit Bear) who almost exclusively resides within the Great Bear Rainforest, alongside its black-furred brothers.

Kermode Bears hold a fascination for many bear watching enthusiasts, due to their long and mysterious history among the Tsimshian people, who believed them to be sacred and hold supernatural powers. But what is it really that causes these beautiful animals to have white fur instead of black?

The Science

The Kermode Bear is a genetic variant of the Black Bear, making it much revered amongst bear watching enthusiasts. Experts describe it as a natural phenomenon called Kermodism, and it has more in common with human genes than you may realise. Many people speculate as to whether its white fur is due to it being albino or even a type of polar bear; in actual fact it is the recessive mutation gene MC1R that causes the change in colour – which is the same gene associated with humans born with red hair and pale skin.

In order to be born with its distinctive vanilla-coloured fur, the animal must inherit the mutation from both of its parents. Unusually, the parents will often carry the gene but not be white themselves, making it common for them to be the product of two black parents.

Areas of Origin

Statistics of Kermode Bears being born varies greatly, depending on the area they are born in. The British Columbia mainland coast sees only one in every 40 to 100 black bears being born with white fur, but within the Great British Rainforest the statistics are much higher.

In particular, Princess Royal Island is one of the major habitats and sees every one in ten Black Bears born with the mutation. Directly north on Gribbell Island, one in three are born with it. For this reason Gribell is very popular with bear watching enthusiasts hoping for a sighting.

Mutation Origin

It is unknown as to where Kermodism originated, but there are many theories surrounding this natural phenomenon. The "glacial bear" hypothesis suggests that Kermodism exists as a remnant adaptation of the last great ice age from 11,000 years ago, when British Columbia was still covered in snow.

Much like the adaptation of white coats that Polar Bears have evolved in order to camouflage in with their surroundings, the glacial bear hypothesis suggests that this is how Kermodism also began. However, this theory raises as many questions as it answers, such as why the white fur mutation has continued on to the present day when it is no longer needed for camouflage.

The theory represents one of many about the Kermode species, which gives some insight into why they have such a mystery surrounding them. Some scientists speculate that their white fur has continued to be a trait due to the advantage it has given them for fishing. Recent research has revealed that during daylight, they are able to catch salmon in a third of their attempts, while Black Bears only manage success a quarter of the time.

Whether or not these theories reveal the true origins of Kermodism is yet to be answered, but they continue to be admired and sought after by many bear watching enthusiasts.

Marissa Ellis-Snow is a freelance nature writer. If you’re looking for bear watching holidays, Naturetrek specialises in expert-led natural history and wildlife tours worldwide. Naturetrek brings over 25 years of experience to polar expeditions and tours to other spectacular regions on Earth.

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