Why are some black bears brown?
American black bears are not all black. They come in brown, blonde, and blue-grey. The colour variations have genetic causes.
Mutation in the pigment gene
American black bears are not all black. They come in various colours, including brown, blonde, and blue-grey. New research findings have found the answer in the genome of the black bear: a mutation in the pigment gene TYRP1. The research was published in Current Biology .
Melanin is the pigment that gives mammals their coat colour. There are two types: eumelanin (black or brown) and phaeomelanin (red or yellow). The researchers found that cinnamon-coloured black bears produce lower amounts of eumelanin.
9’360-year-old mutation
The TYRP1R153C mutation arose spontaneously approximately 9’360 years ago in black bears in the western United States. “The TYRP1R153C mutation has likely given cinnamon-coloured bears an advantage in their current range,” says Dr. Puckett.
The research team proposes a new explanation: crypsis, the ability of an animal to conceal itself through colouration similar to its background. More on the topic of Wildlife.
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