By James L. Cummins

Conservation Corner

Animals come in a variety of colors. In general, each animal species has an expected color or colors. Every now and then an oddly colored animal catches our eye. Most of the time the odd color is a white or light “wash” to the animal, and other times it is a dark or black color. Sometimes it is the entire animal, and other times it is just a patch of fur or a few feathers or scales. These oddly colored animals may be albinistic, leucistic, pie-bald, or melanistic.

In most mammals and birds, the predominant coat color is controlled by cells in the skin, fur, and feathers called melanocytes. Melanocytes produce several different forms of the chemical melanin that control the color. 

Melanin produces black fur, feathers, or scales if it is not modified by some other process. In many amphibians, fish, reptiles, crustaceans, and cephalopods, a more complex color cell called a chromatophore is found in the skin. How both melanocytes and chromatophores produce pigments that reflect light is controlled genetically.

When we have completely black animals with dark eyes and claws, we refer to it as a melanistic animal. If melanin is completely lacking, we have an albino animal that is white with pink eyes and claws. If the melanin has been reduced but some pigment is still present, we call this leucism. Then there are cases where melanin is missing only in portions of an animal where there are patches of white fur, feathers or scales, and we refer to these as pie-bald or pie-bald coloration.

The cells controlling pelage color in these animals retain the ability to produce color, but the color-producing cells are turned off. These patches of white pelage occur most often in reptiles, birds, and mammals. In deer, the expression of a pied-coat is often genetically related to endocrine disorders that produce other effects, such as short legs, a Roman nose, and curvature of the spine.

 Sometimes rather than lacking melanin, the melanin production is not inhibited to allow other colors to be expressed, which results in a completely black individual. Melanistic animals have uniformly dark pelage, claws, and eyes. Every now and then, melanistic deer are harvested. A small percentage of the coyote population is melanistic. Like albinism, melanism can interfere with camouflage and thermo-regulation; it may also interfere with synthesis of vitamin D. Melanistic individuals of some species are more resistant to viral diseases.

The next time an oddly colored animal catches your eye, take a closer look, and see what genetic mechanism might be causing the different color. The color of the coat, whether the color is patchy or covers the entire animal, and the color of the eyes and claws can provide clues to the animal’s genetic traits, whether melanin is present and how melanin has interacted with other color-producing pigments to produce an individual that is noticeably different and unique.

James L. Cummins is executive director of Wildlife Mississippi, a non‑profit, conservation organization founded to conserve, restore, and enhance fish, wildlife, and plant resources throughout Mississippi. Their web site is www.wildlifemiss.org.