Primitive Markings - Primitive Markings in Non-dun Horses

Primitive Markings in Non-dun Horses

Primitive markings can also occur on non-dun horses, even in breeds such as Thoroughbreds, Arabians, and Standardbreds, which are not known to have any dun individuals. The most common primitive marking found is a dorsal stripe; others do occur, but not without the dorsal stripe, even on non-duns.

Dorsal stripes and other primitive markings on non-dun horses are commonly called countershading dorsals because they seldom occur on clear-coated horses. The term countershading refers to any coloration that breaks up the outline of the animal: from a distance, countershaded animals - be they horses or birds - appear two-dimensional and are much more difficult to see. Primitive markings on non-duns are often seasonal, visible only when the horse is shedding its coat. Such primitive markings also seem to be heritable, as horses with prominent countershading dorsals often produce offspring with the same.