COLOR MEANS A LOT IN NATURE

by Whit Gibbons

July 1, 2007

What color is the Fourth of July? For most Americans, red, white, and blue. Halloween is orange and black. Valentine's Day is pink, or red. Color is an important component of our lives and is a defining part of the lives of many plants and animals that tells an environmental story.

Camouflage is a common characteristic of animals whose lifestyles require that they not be easily seen. The spotted coats of adult leopards and baby deer help them hide from the eyes of other animals, prey in the case of leopards, predators in the case of fawns. Although their reasons for having spots are different, both are clearly custom-made for blending into particular habitats. 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. Some or all of the higher primates, which would include humans and baboons, can see colors. The brightly colored rump region of male baboons is the most obvious display of color among the mammals, except for hair color among some of today's teenagers.

Plants also use color to great advantage, the various forms of color advertising being the most apparent. Brightly colored flowers attract insects that are essential for pollination in some species. And few plants can be accused of false advertising as the insect lured to a flower is usually treated to nectar. Bright red or yellow berries that attract birds such as cedar waxwings offer a meal for the bird and assure that the enclosed seed will later be deposited in another area.

Color is also used as a lure in some species of animals. Baby copperheads and cottonmouths have bright yellow tails that are waved enticingly in the presence of small frogs or lizards. Because the rest of the snake is well camouflaged in dead leaves, the frog or lizard becomes prey when focusing its attention on the tail and mistaking it for something to eat.

Flash colors are a special use of color for defense among some animals. For example, the gray treefrog is a perfectly camouflaged creature when sitting on an oak tree or other drab background. When a gray treefrog is pursued by a bird that intends to make a meal of it, the frog jumps and displays bright yellow underparts. Upon landing on a tree and tucking in its legs, the frog blends into the background. The bird, meanwhile, is in search of something yellow that cannot be found.

One color phenomenon, albinism, is not a product of the natural environment of plants and animals. Albinism is the expression of a genetic condition that can be inherited, although neither parent need be an albino itself. An albino is incapable of producing the pigments that normally give color to hair, skin, feathers, and other surface tissues. Because of this abnormal condition, survival in the wild is a difficult struggle.

Ironically, laboratory white rats and mice are the most successful and plentiful albinos in the world. They serve to demonstrate how human intervention in the natural world can have an enormous impact on what constitutes success in a particular environment.



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