Erythrism

Erythrism is a rare genetic mutation that causes an animal to have an unusually reddish or orange coloration. This phenomenon is caused by a deficiency in the production of melanin, the dark pigment responsible for most animal coloration. Instead, the animal's body produces a higher than normal amount of pheomelanin, a reddish-yellow pigment. This results in a reddish or orange hue, which can range from a pale tint to a vibrant shade, depending on the species and the extent of the mutation.

Erythrism is not limited to a single species and has been observed in a wide variety of animals, including mammals, birds, reptiles, and amphibians. For instance, erythristic deer can appear as a reddish-brown color, while erythristic squirrels might have a distinct orange coat. In some cases, the erythristic animal may also have lighter colored eyes, often pink or red, due to the lack of pigment in the iris.

Unlike albinism, which results in a complete lack of pigment, or melanism, which leads to an excess of dark pigment, erythrism specifically affects the balance between melanin and pheomelanin. The genetic basis for erythrism can vary, but it generally involves a mutation in genes that regulate pigment production. While it is a genetic trait, it does not typically impact the animal's health or lifespan, although it can make them more conspicuous to predators due to their unusual coloration.