Melanism in the rock pocket mouse
Light- and dark-colored Chaetodipus intermedius from the Pinacate region of Arizona are shown on sandy-colored and dark lava-rock backgrounds.
[Michael Nachman, from M. W. Nachman et al., “The Genetic Basis of Adaptive Melanism in Pocket Mice,” Proc. Natl. Acad. Sci. USA 100, 2003, 5268-5273.]