Albinism is an inherited mutation that causes a lack (albinoid) or absence (albino) of melanin, the primary skin pigment.
(Image: Canaille Blog)
There are several drawbacks for an animal born with albinism. For most, it strips away their camouflage ability, since creatures of a brilliant white will stand out in almost any setting. Because of the lack of protective pigments in the skin, they are more prone to sun damage. Many of them also experience congenital eye conditions that accompany the trait. Without pigmentation, the blood cells beneath the skin and tissues are visible, making the eyes of albinos often appear pink or red.
Leucism is a type of albinism that affects the skin and hair or feathers, but does not affect the eyes.
Certain species of otherwise normally colored animals have genetic subspecies that are mostly or entirely white.
White bengal tiger: Wikimedia Commons (CC-BY-3.0) by Averette
The mesmerizing beauty and mystery of these “ghost animals” have made them revered in many cultures since prehistoric times. They are often seen as divine messengers and it is taboo to harm them (such as the white buffalo of the Plains Indians). In modern times, this fascination has turned against them, making them popular in captive exhibits and the hides and other remains prized specimens for hunters and collectors. Albino and leucistic animals are now protected by law in many parts of the world.
Melanism is the exact opposite condition; it’s the result of overproduction of pigments. Usually this is manifested in the phantom “black animals” that appear from time to time in a population. Unlike albinos, darker animals have an almost universal survival advantage (unless they live in the Arctic, for example) because it is easier for them to blend in with their surroundings.
Melanism in a gene pool can quickly become a dominant trait – as in the case of the Yellowstone wolves. (NATURE: In the Valley of the Wolves)
TALKBACK: What’s your favorite albino animal?
- Big cats