Hereditary changes in melanin production that cause the darkening in color of populations of animals in darkened surroundings. By improving their camouflage, this makes them less conspicuous to predators. For example, desert mice are preyed upon by owls, hawks, and foxes. The mice that live among sand and light-colored rocks are tan and blend in well with their surroundings. However, the fur from populations of the same species that live among outcrops of dark, ancient lava flows is much darker. See Chaetodipus intermedius.
Subjects: Genetics and Genomics.