OUTDOOR COLUMN: NATURE'S SHADE OF WHITE: WHITE DOESN'T NECESSARILY MEAN ALBINO

Have you ever seen a white animal?

Every white animal seen in the field is labeled as an albino. This is a good assumption and it would seem the education system has done its job.

A majority of people recall discussions about heredity and how albinos come to be. However, there is seldom time to discuss other causes of being white. Albinism is not the only reason for lack of color. The cause can be genetic or developmental.

Normal animals produce pigment, and this usually serves a purpose. The pigment can be most any color, but it seems that camouflage is a very popular use of color. Fish, mammals, birds, reptiles, amphibians, insects, arachnids and many others make use of concealing coloration. Sometimes animals use vivid, easily seen colors to advertise their presence in order to attract a mate. Ducks, and warblers are a good example of advertisement coloration. Still, others like to be brightly colored to attract attention for another reason.

Newts are bright salamanders that taste very bad if eaten by predators. The bright orange of the belly serves as a warning to any hungry predator. Coloration also prevents a certain amount of damage from ultraviolet radiation. That is why our skin darkens in response to solar radiation; this is called tanning.

Bear in mind that no matter how rare it is to become white, it is even more rare to survive as a white animal. Whatever use your color may be, when you are born without it, you no longer have the benefit of that coloration. So if your coloration camouflages, then you will be more easily seen. If your color is for mating, white may not attract a mate. If the color is for UV protection, you will be subject to cataracts, skin cancer and even sunburn. Thus, lacking color is a strike against you in the game of survival.

To be an albino your body cannot produce any pigment (melanin). This is a result of an inherited trait from both parents. The genetic code for your coloration has multiple forms. This is called an allele. An example in humans would be hair color. One allele codes for red hair while another codes for dark, and another for blonde.

Everyone has an allele pair for every trait. Your coloration is dependant on what alleles you possess. Albinos have two alleles that do not produce pigment. If you have only one allele that does not make color, the working allele will make color for you. True albinos have pink eyes, pink hooves or claws or nails, and have entirely white skin, fur, scales or feathers. They have pink because without pigment the blood shows through. An albino whitetail deer was harvested from Missouri not long ago.

Leucistic animals are white but have blue or black eyes. This is genetic condition as well. The lack of color is localized only to the skin. You may remember the white alligator King Louie' from the Saint Louis Zoo that was leusistic.

Amelanistic (means without color) animals are animals that have a cellular defect. While they are in the womb the cells divide and chromosomes, the carriers of DNA, are divided up equally so each new cell has a full set.

However, sometimes one cell gets all the color genes and another gets none. The rest of the chromosomes are divided as needed but the color genes are not. This produces an animal that is partially white and colored. It is almost a patchwork quilt. Madison county recently had an amelenistic River Otter in its streams.

Some animals are white some of the time and others are white permanently. Long tail and least weasels are a good example of an animal that grows a white pelt for winter and is dark in the summer. Yet it is not an albino, leucistic, or amelanistic. It just has a seasonal change that is cued up by different set of inherited traits.

Cave animals, such as the southern cave fish, cave crayfish, grotto salamander, and many others, are all permanently white. Color is of no use to them and it is energetically expensive to make, so there is no penalty for loosing the ability to make color. They are entire populations of albinos.

Finally, there are partial albinos. Some colorations are results of two colors mixing together. A green treefrog has yellow and blue pigments that are totally separate. If a genetic defect occurs one of the pigments is not produced and the frog will be either yellow or blue but not green. This is partial albinism, when some pigment is produced but not all of it is gone.

Seeing an oddly colored animal is a very rare thing indeed. If you are one of lucky ones to see a white animal, be sure to enjoy the moment. You will be a member of a very small club of people that will ever see an abnormally white animal.

A.J. Hendershott is an education consultant with the Missouri Department of Conservation.