page_title: Equine coat color
section_title: Basic coat colors
hierarchical_section_title: Equine coat color / Basic coat colors
caption_attribution_description: Wild stallion Lazarus and part of his band in West Warm Springs HMA, OR
context_page_description: Horses exhibit a diverse array of coat colors and distinctive markings. A specialized vocabulary has evolved to describe them.
  While most horses remain the same color throughout life, a few, over the course of several years, will develop a different coat color from that with which they were born. Most white markings are present at birth, and the underlying skin color of a healthy horse does not change.
  The basic outline of equine coat color genetics has largely been resolved, and DNA tests to determine the likelihood that a horse will have offspring of a given color have been developed for some colors. Discussion, research, and even controversy continues about some of the details, particularly those surrounding spotting patterns, color sub-shades such as "sooty" or "flaxen", and markings.
context_section_description: The two basic hair colors of horses are red (a reddish brown color) and black. 
  These two hair colors give three basic coat colors: bay, which has both red and black hairs, chestnut, which is fully red, and black, which is fully black. 
  Bay: Body color ranges from a light reddish-brown to rich chocolate brown with "black points". (Points refer to the mane, tail, and lower legs.) The main color variations are:
  Dark Bay: a dark brown coat with black points, difficult to distinguish from seal brown. Sometimes also called "black bay"
  Mahogany Bay: a dark red brown coat with black points
  Blood Bay/Red Bay: a bright red chestnut coat with black points
  Brown: The word "brown" is used by some breed registries to describe dark bays. There is a distinct allele that darkens a bay coat to seal brown (At), but it is not the cause of all forms of dark bay. Informally, "brown" is applied to many distinct coat colors. Most often, horses described by casual observers as "brown" are actually bay or chestnut. In the absence of DNA testing, chestnut and bay can be distinguished from each other by looking at the mane, tail and legs for the presence of black points.
  Chestnut: A red brown coat with no black. The mane and tail are the same shade of chestnut or lighter chestnut than the body coat. The main color variations are:
  Liver Chestnut: very dark red chestnut coat. Sometimes a liver chestnut is also simply called "brown".
  Sorrel: Reddish-tan coat, about the color of a new penny. The most common shade of chestnut.
  Light Chestnut: seldom-used term for a pale chestnut coat, mane, and tail
  Flaxen Chestnut: Any shade of chestnut, with a blond mane and tail
  Black: Black is relatively uncommon, though it is not "rare". There are two types of black, fading black and non-fading black. Most black horses will fade to a brownish color if the horse is exposed to sunlight regularly. Non-fading black is a blue-black shade that does not fade in the sun.  Genetically, the two cannot yet be differentiated, and some claim the difference occurs due to management rather than genetics, though this claim is hotly disputed. Most black foals are usually born a mousy grey or dun color. As their foal coat begins to shed out, their black color will show through, though in some breeds black foals are born jet black. For a horse to be considered black, it must be completely black except for white markings. A sun-bleached black horse is still black, even though it may appear to be a dark bay or brown. A visible difference between a true black and a dark chestnut or bay is seen in the fine hairs around the eyes and muzzle; on a true black these hairs are black, even if the horse is sun-bleached, on other colors, they will be lighter.
  Genetically, a chestnut horse is a bay or black horse that cannot signal pigment cells to produce black pigment, while a black horse is a bay horse that cannot cancel the signal to produce black pigment.  The extension gene determines whether the cells can decide to produce black, and can be either E (able to produce black) or e (only able to produce red, as in chestnut). To be chestnut a horse must have two copies of e, so the genotype is e/e. A horse with a genotype of E/E or E/e can still make black pigment and will be bay or black. Meanwhile the agouti gene determines whether the cells can stop producing black. The A version of agouti means that it can, so as long as has E at extension the base color will be bay. The a version of agouti means the cells cannot stop producing black, so a horse with two copies of a (genotype a/a) and E at extension will be black rather than bay. 
  So together these two genes control the two pigments to make the three base colors. The vast range of all other coat colors are created by additional genes' action upon one of these base colors.
caption: Bay (left) and chestnut (right) mustangs.
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