Numerous examples exist for which the environment dictates the color pattern, whether for protection of a prey species or for stealth in a predator. Color is a common feature among birds, most of which can see color, for purposes of breeding. Male goldfinches turn bright yellow and male indigo buntings turn bright blue in the spring during the mating season. Redwing blackbird males display bright red and yellow epaulets on their wings. The females of the latter two species are an unimaginative brown, and the female goldfinch is a much paler yellow than the male.
Many fish are also distinctive in their color differences between the sexes.
The brilliantly colored darters of the southeastern streams are dramatic in their contrast between males and females. In the male Christmas darter of Georgia and South Carolina, bright red and green bars are present during the breeding season. Males of the redband darter of Tennessee sport bright blue and red orange on their fins. Female darters are generally drabber in appearance. Interestingly, the color of most mammals is restricted to whites, browns, grays, and black, suggesting that color blindness is a common trait within the group.