Dans National Geographic du mois d'aout 2011, des photos d'ours noirs qui sont blancs. Comme on l'explique dans l'article il ne s'agit pas d'albinos mais d'un phénomène observé en Colombie Britannique, d'une modification génétique, si les 2 parents ont le gène le petit va venir au monde blanc, même si ses 2 parents sont des ours noirs.
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From National Geographic:
Neither albino nor polar bear, the spirit bear (also known as the Kermode bear) 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 and encompasses 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 a coast that has been home to First Nations like the Gitga'at for hundreds of generations. It's a spooky, wild, mysterious place: There are wolves here that fish. Deer that swim. Western red cedar trees that have stood a thousand years or more. And a black bear that is white....
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. 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 occurs in only one of every 40 to 100 black bears on the British Columbia mainland coast, but the trait is especially pronounced on certain islands in the Great Bear Rainforest.
The photos can be found in the August 2011 issue of National Geographic magazine, on newsstands now.
Neither albino nor polar bear, the spirit bear (also known as the Kermode bear) 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 and encompasses 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 a coast that has been home to First Nations like the Gitga'at for hundreds of generations. It's a spooky, wild, mysterious place: There are wolves here that fish. Deer that swim. Western red cedar trees that have stood a thousand years or more. And a black bear that is white....
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. 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 occurs in only one of every 40 to 100 black bears on the British Columbia mainland coast, but the trait is especially pronounced on certain islands in the Great Bear Rainforest.
The photos can be found in the August 2011 issue of National Geographic magazine, on newsstands now.
