Chapter 2: Horses in Size
Listings
Chapter 4: Reproduction in Horses
Horses exhibit a diverse array of coat colors and distinctive markings, described with a specialized vocabulary. Often, a horse is classified first by its coat color, before breed or sex. Flashy or unusual colors are sometimes very popular, as are horses with particularly attractive markings. Horses of the same color may be distinguished from one another by their markings.
The genetics that create many horse coat colors have been identified, although research continues on specific genes and mutations that result in specific color traits. Essentially, all horse colors begin with a genetic base of "red" (chestnut) or "black", with the addition of alleles for spotting, graying, suppression or dilution of color, or other effects acting upon the base colors to create the dozens of possible coat colors found in horses.
Horses which are light in color are often misnamed as being "white" horses. A horse that looks pure white is, in most cases, actually a middle-aged or older gray. Grays have black skin underneath their white hair coat (with the exception of small amounts of pink skin under white markings). The only horses properly called white are those with pink skin under a white hair coat, a fairly rare occurrence. There are no truly albino horses, with pink skin and red eyes, as albinism is a lethal condition in horses.
Genetically, all horses start out as either chestnut, called "red" by geneticists, represented by the absence of the extension gene ("e"); or "non-red," based on the presence of the extension gene ("E"). "Non-red" horses start out with a base coat of black, or with another common genetic modifier, the Agouti gene ("A"), bay. The vast range of all other coat colors are created by additional genes action upon one of these three base coat colors.
The horse color phenotypes are:
Basic Colors--
•Bay:
Body color ranges from a light reddish-brown to very dark brown with "black points." (Points refer to the mane, tail, and lower legs). The main color variations are:
Dark bay: very dark red or brown hair, often difficult to distinguish from seal brown. Sometimes also called "black bay," "mahogany bay," or "brown."
Blood bay: bright red hair, the shade variation often considered simply "bay."
Light bay: lighter than a blood bay, but hairs still clearly more red than gold
Brown: The word "brown" can apply many distinct coat colors. Most often, horses described by casual observers as "brown" are bay (see above) or chestnut (see below). Absent DNA testing, chestnut and bay can be distinguished from one another by looking closely at the mane, tail and legs for the presence of black points. However, true seal brown is distinct from both bay and chestnut.
Liver chestnut: very dark brown coat. Sometimes a liver chestnut is also simply called "brown."
Sorrel: Reddish-tan to red coat, about the color of a new penny. The most common shade of chestnut.
Blond or light chestnut: seldom-used term for lighter tan coat with pale mane and tail that is not quite a dun.
Salt and Pepper or "steel" gray: Usually a younger horse, an animal with white and dark hairs evenly intermixed over most of the body.Other Colors--
Dapple gray: a dark-colored horse with lighter rings of graying hairs, called dapples, scattered throughout.
Fleabitten gray: an otherwise fully white-haired horse that develops red hairs flecked throughout the coat.
Rose gray: a gray horse with a reddish or pinkish tinge to its coat. This color occurs with a horse born bay or chestnut while the young horse is "graying out."
*Albino: There are no "albinos", defined as animals with a white coat with pink skin and pink eyes, in the horse world. The genetic factors that create albinism, for reasons not yet fully understood, are lethal in horses. If a foal is conceived as a homozygous "dominant white," the mare will either abort the foal or reabsorb the embryo. A foal with Lethal white syndrome dies shortly after birth. However, some horses are born with white hair, blue or brown eyes, and unpigmented skin that are healthy. See "white" color, below for description of a truly white horse.•Black: Black is relatively uncommon, though 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 on a regular basis. 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.
Grulla, Grullo or Blue Dun: A horse with a black base color and the dun gene. Coat is solid "mouse-colored" gray or silver with black or dark gray primitive markings.•Leopard or Appaloosa: There are a group of coat patterns caused by the leopard gene complex. It should be noted that not every horse with leopard genetics will exhibit hair coat spotting. However, even solid individuals will exhibit secondary characteristics such as vertically striped hooves, mottled skin around the eyes, lips, and genitalia, plus a white sclera of the eye. Several breeds of horse can boast leopard-spotted (a term used collectively for all patterns) individuals including the Knabstrup, Noriker, and the Appaloosa. There are several distinct leopard patterns:
Red dun: A chestnut base coat with dun factors. Coat is usually pale yellow or tan with chestnut (red) primitive markings.
"bay dun" or "zebra dun": are terms sometimes used to describe the classic dun color of yellow or tan with black primitive markings, used when necessary to distinguish it from red duns or grullos.
"Buckskin dun": describes a dun that also carries the cream gene dilution and has a coat of pale gold with black mane, tail, legs and primitive markings.
blanket: white over the hip that may extend from the tail to the base of the neck. The spots inside the blanket (if present) are the same color as the horse's base coat.•Palomino: chestnut horse that has one cream dilution gene that turns the horse to a golden, yellow, or tan shade with a flaxen or white mane and tail. Often cited as being a color "within three shades of a newly minted gold coin," palominos range in shades from extremely light, almost cremello, to deep chocolate, but always with a white or flaxen mane and tail.
varnish roan: a mix of body and white hairs that extends over the entire body--no relation to true roan.
snowflake: white spots on a dark body. Typically the white spots increase in number and size as the horse ages.
leopard: dark spots of varying sizes over a white body.
few spot leopard: a nearly white horse from birth that retains color just above the hooves, the knees, 'armpits', mane and tail, wind pipe, and face.
frost: similar to varnish but the white hairs are limited to the back, loins, and neck.
Piebald: a black and white spotting pattern (term more commonly used in the UK than the USA)•Rabicano: A roan-like effect that is caused by a genetic modifier that creates a mealy, splotchy, or roaning pattern on only part of the body, usually limited to the underside, flanks, legs, and tail head areas. Unlike a true roan, much of the body will not have white hairs intermingled with solid ones, nor are the legs or head significantly darker than the rest of the horse.
Skewbald: a spotting pattern of white and any other color other than black, or a spotting pattern of white and two other colors, which may include black. (term more commonly used in the UK than the USA).
Overo: Describes a group of spotting patterns genetically distinct from one another, characterized by sharp, irregular markings with a horizontal orientation, usually more dark than white. In some cases, the face is usually white, often with blue eyes. The white rarely crosses the back, and the lower legs are normally dark. Variations include "Frame Overo" and "Splashed white." Sometimes Sabino below is also classified in the overo family.
Sabino: Often confused with roan or rabicano, a slight spotting pattern characterized by high white on legs, belly spots, white markings on the face extending past the eyes and/or patches of roaning patterns standing alone or on the edges of white markings.
Tobiano: Spotting pattern characterized by rounded markings with white legs and white across the back between the withers and the dock of the tail, usually arranged in a roughly vertical pattern and more white than dark, with the head usually dark and with markings like that of a normal horse. i.e. star, snip, strip, or blaze.
Tovero: spotting pattern that is a mix of tobiano and overo coloration, such as blue eyes on a dark head. May also refer to horses with Tobiano coloring that carry a recessive overo gene.
Paint: pinto horses with known Quarter Horse and/or Thoroughbred bloodlines. This is a separate breed of horse.
Red Roan: A chestnut base coat with roaning pattern with the mane and tail being the same red as the body. Red roans are also commonly referred to as a Strawberry Roan, and the term Red Roan is occasionally is used to describe a Bay Roan.•Silver dapple: Caused by a dilution gene that only acts upon black hair pigment, it lightens black body hair to a chocolate brown and the mane and tail to silver. The gene may be carried but will not be visible on horses with a red base coat. Silver dapple horses may also be called Chocolate, Flax, or Taffy.
Bay Roan: A Bay base coat with roaning pattern (the mane and tail of the Bay Roan will be Black). Bay roans are sometimes also called Red Roans. Blue Roan: A black with roaning pattern, not to be confused with a gray or a blue dun/grullo. A roan tends to have a darker head, while grays not only lighten with age, but their heads tend to lighten before the rest of their bodies. A blue roan has mixed-color hairs, a blue dun will usually be a solid color and have dun striping.
