Black bears have become lighter due to a mutation in the genes.

Zoologists have found that baribals (black bears) in the west of North America are colored in lighter colors due to a mutation in the TYRP1 gene. It interferes with the normal synthesis of the eumelanin pigment responsible for coat color. In humans, mutations in the TYRP1 gene cause oculocutaneous albinism, in which vision is impaired and the skin and hair become reddish. In bears, this mutation does not cause these problems.