Fun Fact: can horses have blue eyes?

The blue-eyed horse is shrouded in myth and legend. In the past, many associated the rarity of this color with negative traits such as madness or untrustworthiness. Some even believed that such horses were more prone to tumors. In gypsy lore, a horse with blue eyes was believed to have a piece of heaven in its eyes.

Most horses possess brown eyes, but in some breeds, such as the Akhal-Teke, Paint and Appaloosa, it is possible to find specimens with blue eyes, called “gazelles.” In even rarer cases, the iris may be green or even purple.

Eye color is determined by the pigmentation of the iris, which surrounds the pupil. Hue depends on melanin concentration: dark eyes indicate a high amount of melanin, while light eyes contain less.

In addition to blue eyes, horses can also have other ocular peculiarities, such as heterochromia and mosaicism.

Heterochromia is a condition in which an animal has eyes of different colors, usually one blue and the other black or brown. It is caused by an uneven distribution of melanin, but does not affect the quality of vision.

Mosaicism, on the other hand, occurs when one eye has multiple colors. In this case, the iris appears bichromatic. Mosaicism is often congenital and genetically transmitted, but if it appears later it may be the result of trauma or signal the presence of a disease.