Black (horse)

Black
	Black Irish Draught horse
Variants	Fading, non-fading, possibly genetic
Genotype
Base color	Extension "E"
Modifying genes	none
Description	Solid black base color uniform over entire body other than markings
Skin	Black
Eyes	Brown

Last updated November 04, 2019

Black is a hair coat color of horses in which the entire hair coat is black. Black is a relatively uncommon coat color, and it is not uncommon to mistake dark chestnuts or bays for black.

Equine coat color Horse coat colors and markings

Horses exhibit a diverse array of coat colors and distinctive markings. A specialized vocabulary has evolved to describe them.

The horse is one of two extant subspecies of Equus ferus. It is an odd-toed ungulate mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature, Eohippus, into the large, single-toed animal of today. Humans began domesticating horses around 4000 BC, and their domestication is believed to have been widespread by 3000 BC. Horses in the subspecies caballus are domesticated, although some domesticated populations live in the wild as feral horses. These feral populations are not true wild horses, as this term is used to describe horses that have never been domesticated, such as the endangered Przewalski's horse, a separate subspecies, and the only remaining true wild horse. There is an extensive, specialized vocabulary used to describe equine-related concepts, covering everything from anatomy to life stages, size, colors, markings, breeds, locomotion, and behavior.

Chestnut is a hair coat color of horses consisting of a reddish-to-brown coat with a mane and tail the same or lighter in color than the coat. Chestnut is characterized by the absolute absence of true black hairs. It is one of the most common horse coat colors, seen in almost every breed of horse.

True black horses have dark brown eyes, black skin, and wholly black hair coats without any areas of permanently reddish or brownish hair. They may have pink skin beneath any white markings under the areas of white hair, and if such white markings include one or both eyes, the eyes may be blue. Many black horses "sun bleach" with exposure to the elements and sweat, and therefore their coats may lose some of their rich black character and may even resemble bay or seal brown, though examination of the color of hair around the eyes, muzzle and genitals often will determine color. Black horses that do not sun bleach are called "non-fading" blacks.

Markings on horses are usually distinctive white areas on an otherwise dark base coat color. Most horses have some markings, and they help to identify the horse as a unique individual. Markings are present at birth and do not change over the course of the horse's life. Most markings have pink skin underneath most of the white hairs, though a few faint markings may occasionally have white hair with no underlying pink skin. Markings may appear to change slightly when a horse grows or sheds its winter coat, however this difference is simply a factor of hair coat length; the underlying pattern does not change.

Seal brown is a hair coat color of horses characterized by a near-black body color; with black points, the mane, tail and legs; but also reddish or tan areas around the eyes, muzzle, behind the elbow and in front of the stifle. The term is not to be confused with "brown", which is used by some breed registries to refer to either a seal brown horse or to a dark bay without the additional characteristics of seal brown genetics.

Some breeds of horses, such as the Friesian horse, Murgese and Ariegeois (or Merens) are almost exclusively black. Black is also common in the Fell pony, Dales pony, Ostfriesen and Alt-Oldenburger, Kladruber, and Groningen.

The Friesian is a horse breed originating in Friesland, in the Netherlands. Although the conformation of the breed resembles that of a light draught horse, Friesians are graceful and nimble for their size. It is believed that during the Middle Ages, ancestors of Friesian horses were in great demand as war horses throughout continental Europe. Through the Early Middle Ages and High Middle Ages, their size enabled them to carry a knight in armour. In the Late Middle Ages, heavier, draught type animals were needed. Though the breed nearly became extinct on more than one occasion, the modern day Friesian horse is growing in numbers and popularity, used both in harness and under saddle. Most recently, the breed is being introduced to the field of dressage.

The Murgese horse originated in the Murge, Apulia area of Italy during the Spanish rule, and was developed from Barb and Arabian horses. They are a hardy breed that is used mainly for cross-country riding, although they have also been used for light draft work.

The Fell Pony is a versatile, working breed of mountain and moorland pony originating in the north of England in Cumberland and Westmorland (Cumbria) and Northumberland. It was originally bred on the fell farms of northwest England, and is used as a riding and driving pony. The breed is closely related to its geographic neighbour, the Dales Pony, but is a little smaller and more pony-like in build. The Fell Pony is noted for hardiness, agility, strength, and sure-footedness.

Visual identification

Black horse (top) with sun bleached mane compared against dark bay or seal brown horse (bottom) with reddish hairs around the eye. Brownvblack.JPG — Black horse (top) with sun bleached mane compared against dark bay or seal brown horse (bottom) with reddish hairs around the eye.

When identifying the base color of a horse, it is important to disregard all pink-skinned white markings. White markings and patterns such as pinto and leopard have no bearing on the underlying base coat color of the animal.

A pinto horse has a coat color that consists of large patches of white and any other color. The distinction between "pinto" and "solid" can be tenuous, as so-called "solid" horses frequently have areas of white hair. Various cultures throughout history appear to have selectively bred for pinto patterns.

Black foals are typically born a mousy gray but can be darker shades. As many foals have primitive markings at birth, some black foals are mistaken for grullo or even bay dun; the primitive markings on a black foal will, however, disappear as the black hair coat grows in. Black foals have dark skin and eyes at birth. An adult-like black foal coat often indicates that the foal will gray, if the foal has at least one gray parent. Graying can be confirmed by the presence of white hairs around the eyes and muzzle. Gray Lipizzaner horses are frequently born black.

Foal A horse of either sex up to the age of one year

A foal is an equine up to one year old; this term is used mainly for horses. More specific terms are colt for a male foal and filly for a female foal, and are used until the horse is three or four. When the foal is nursing from its great (mother), it may also be called a "suckling". After it has been weaned from its dam, it may be called a "weanling". When a mare is pregnant, she is said to be "in foal". When the mare gives birth, she is "foaling", and the impending birth is usually stated as "to foal". A newborn horse is "foaled".

Primitive markings are a group of hair coat markings and qualities seen in several equine species, including horses, donkeys, and asses. In horses, they are associated with primitive breeds, though not limited to such breeds. The markings are particularly associated with the dun coat color family. All dun horses possess at least the dorsal stripe, but the presence of the other primitive markings varies. Other common markings may include horizontal striping on the legs, transverse striping across the shoulders, and lighter guard hairs along the edges of a dark mane and tail.

Grullo Color of horses in the dun family

Grullo or grulla, also called blue dun, gray dun or mouse dun, is a color of horses in the dun family, characterized by tan-gray or mouse-colored hairs on the body, often with shoulder and dorsal stripes and black barring on the lower legs. In this coloration, each individual hair is mouse-colored, unlike a roan, which is composed of a mixture of dark and light hairs. The several shades of grulla are informally referred to with a variety of terms, including black dun, blue dun, slate grulla, silver grulla or light grulla, silver dun, or lobo dun. Silver grulla may also refer to a grullo horse with silver dapple, regardless of shade. In the Icelandic horse, the grulla color is called gray dun, in the Highland pony it is called mouse dun, and in the Norwegian Fjord horse, grå or gråblakk.

Black adult horses are easier to identify, as the coat must be entirely black, even if superficially sun bleached. A sun bleached black may be confused with a dark bay, but a trained eye can distinguish between them, particularly by examining the fine hairs around the eyes and muzzle. When a black horse is sun-bleached, the mane and tail often sun bleach most prominently, and the rest of the coat may have a rusty tinge. A sun-bleached black may also be mistaken for the less common smoky black, but can be distinguished by pedigree analysis or DNA testing.

Bay is a hair coat color of horses, characterized by a brown body color with a black mane, tail, ear edges, and lower legs. Bay is one of the most common coat colors in many horse breeds.

Smoky black is a hair coat color of horses in which the coat is either black or a few shades lighter than true black. Smoky black is produced by the action of a heterozygous cream gene on an underlying black coat color. Therefore, smoky black is a member of the cream family of coat color dilutions, and found in horse populations that have other cream gene-based colors such as palomino, buckskin, perlino and cremello. All smoky blacks must have at least one parent with the cream gene, and a smoky black can be verified through DNA testing. Smoky black has been mistaken for faded black, dark bay or brown, grullo or even liver chestnut.

Black mimics

Dark bay or seal brown: The darkest shades of bay are commonly confused with black, even by experienced horse persons. However, a dark bay will always show some rich red character in its coat. Horses with a very dark coat that may appear black, but have tan or reddish hairs around the eyes, muzzle, armpits, and stifle are sometimes called "seal brown", "mahogany bay", or "black bay." Both colors are genetically distinct from black and can be confirmed with a DNA test.
Liver chestnut: Some red horses are so dark that they appear black, and are often called "black chestnuts" as a consequence. However, even the darkest liver chestnuts will show some red character in their coats, usually in the hair around the pastern or in the mane or tail. Even dark liver chestnuts do not have any true black pigment in their coats. This can be verified with DNA testing. Liver chestnut is very common in the Morgan horse.
Smoky black: The action of the cream gene in the heterozygous condition has a minimal effect on black pigment, so heterozygous creams with a black base coat (smoky blacks) differ little from true blacks. A smoky black will have at least one cream parent, is often born a pewter shade with blue eyes, and usually retains reddish hair inside the ear through adulthood.

Genetic identification

In the study and discussion of equine coat color genetics, black is considered a "base" color, as is red. This designation makes the effects of other coat color genes easier to understand. Coat colors that are designated "black-based" include grullo (also called blue dun), smoky black, smoky cream, silver black, classic champagne, and blue roan. Sometimes this designation includes the bay family: bay, seal brown, buckskin, bay dun, silver bay, perlino, amber champagne, and bay roan. Horses with a black-based coat may also have added spotting patterns including leopard patterns seen on Appaloosas and the pinto coloring known as piebald.

The genetics behind the black horse are relatively simple. The color black is primarily controlled by two genes: Extension and Agouti. The functional, dominant allele of the extension gene (labeled "E") enables the horse to produce black pigment in the hair. Without this gene (homozygous recessive condition "ee"), the coat is devoid of black pigment and the horse is some shade of red. The functional, dominant allele (or alleles) of the agouti gene (labeled "A") enable the horse to restrict black pigment to certain parts of the coat, notably the legs, mane and tail, allowing the underlying red to show through, resulting in bay coloring. Without this gene (homozygous recessive condition "aa"), any black pigment present is unrestricted, resulting in a uniformly black coat.

Thus a black horse has at least one copy of the functional, dominant "E" allele and two copies of the non-functional, recessive "a" allele. A mature true black horse can be safely said to possess at least one dominant extension gene (EE or Ee); and has no other dominant genes (such as agouti, gray, or any of the dilution factors) that further modify color.

A DNA test, which uses hair with the root intact, has been developed to test for the Extension and Agouti genotypes. However, the terminology can be manipulated. Unfortunately, the extension test is often mislabeled as the "black test", leading to confusion. Neither the extension test nor the agouti test alone can identify a black horse. Together, they can determine that a horse that appears visually black is not actually a dark bay or liver chestnut.

Horses described as "homozygous black" are simply homozygous for the dominant extension gene (EE); they are homozygous "not-red". Such horses are only "guaranteed" to never produce a red foal. The actual horse may carry additional genetic modifiers that could make it bay, buckskin, gray, bay roan, perlino, silver bay, and so on. A visually black horse that is tested "homozygous black" is EE and has no other color modifiers.

However, it has become popular for individuals owning a horse that is homozygous for the extension gene (EE) to claim that the horse will "throw black." But, generally speaking, one horse cannot be guaranteed to "throw black" with all mates. The mate of a true black horse may contribute the a dominant Agouti allele, which will suppress the black coloring and result in a bay foal. If a black is bred to a gray, the ensuing foal may also be gray. Other modifiers present in the mate may produce additional dilution colors or spotting patterns. Nonetheless certain individual pairings with appropriate DNA testing can, in some cases, be guaranteed to produce black.

Related Research Articles

Roan is a coat color found in many animals, including horses, cattle, antelope and dogs. It is defined generally as an even mixture of white and pigmented hairs that do not "gray out" or fade as the animal ages. There are a variety of genetic conditions which produce the colors described as "roan" in various species.

Palomino is a genetic color in horses, consisting of a gold coat and white mane and tail, the degree of whiteness can vary from bright white to yellow. Genetically, the palomino color is created by a single allele of a dilution gene called the cream gene working on a "red" (chestnut) base coat. Palomino is created by a genetic mechanism of incomplete dominance, hence it is not considered true-breeding. However, most color breed registries that record palomino horses were founded before equine coat color genetics were understood as well as they are today, therefore the standard definition of a palomino is based on the visible coat color, not heritability nor the underlying presence of the dilution gene.

A dilution gene is any one of a number of genes that act to create a lighter coat color in living creatures. There are many examples of such genes:

Gray or grey is a coat color of horses characterized by progressive silvering of the colored hairs of the coat. Most gray horses have black skin and dark eyes; unlike many depigmentation genes, gray does not affect skin or eye color. Their adult hair coat is white, dappled, or white intermingled with hairs of other colors. Gray horses may be born any base color, depending on other color genes present. White hairs begin to appear at or shortly after birth and become progressively lighter as the horse ages. Graying can occur at different rates—very quickly on one horse and very slowly on another.

Cream gene gene responsible for a number of horse coat colors

The cream gene is responsible for a number of horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if they are homozygous. Similarly, horses with a bay base coat and the cream gene will be buckskin or perlino. A black base coat with the cream gene becomes the not-always-recognized smoky black or a smoky cream. Cream horses, even those with blue eyes, are not white horses. Dilution coloring is also not related to any of the white spotting patterns.

The champagne gene is a simple dominant allele responsible for a number of rare horse coat colors. The most distinctive traits of horses with the champagne gene are the hazel eyes and pinkish, freckled skin, which are bright blue and bright pink at birth, respectively. The coat color is also affected: any hairs that would have been red are gold, and any hairs that would have been black are chocolate brown. If a horse inherits the champagne gene from either or both parents, a coat that would otherwise be chestnut is instead gold champagne, with bay corresponding to amber champagne, seal brown to sable champagne, and black to classic champagne. A horse must have at least one champagne parent to inherit the champagne gene, for which there is now a DNA test.

Silver dapple gene also known as the "Z" gene, that dilutes the black base coat color in horses

The silver or silver dapple (Z) gene is a dilution gene that affects the black base coat color. It will typically dilute a black mane and tail to flaxen, and a black body to a shade of brown or chocolate. It is responsible for a group of coat colors in horses called "silver dapple" in the west, or "taffy" in Australia. The most common colors in this category are black silver and bay silver, referring to the respective underlying coat color.

Equine coat color genetics determine a horse's coat color. Many colors are possible, but all variations are produced by changes in only a few genes. Extension and agouti are particularly well-known genes with dramatic effects. Differences at the agouti gene determine whether a horse is bay or black, and a change to the extension gene can make a horse chestnut instead. Most domestic horses have a variant of the dun gene which saturates the coat with color so that they are bay, black, or chestnut instead of dun, grullo, or red dun. A mutation called cream is responsible for palomino, buckskin, and cremello horses. Pearl, champagne and silver dapple also lighten the coat, and sometimes the skin and eyes as well. Genes that affect the distribution of melanocytes create patterns of white such as in roan, pinto, leopard, white, and even white markings. Finally, the gray gene causes premature graying, slowly adding white hairs over the course of several years until the horse looks white. Some of these patterns have complex interactions.

The dun gene is a dilution gene that affects both red and black pigments in the coat color of a horse. The dun gene lightens most of the body while leaving the mane, tail, legs, and primitive markings the shade of the undiluted base coat color. A dun horse always has a dark dorsal stripe down the middle of its back, usually has a darker face and legs, and may have transverse striping across the shoulders or horizontal striping on the back of the forelegs. Body color depends on the underlying coat color genetics. A classic "bay dun" is a gray-gold or tan, characterized by a body color ranging from sandy yellow to reddish brown. Duns with a chestnut base may appear a light tan shade, and those with black base coloration are a steel gray. Manes, tails, primitive markings, and other dark areas are usually the shade of the undiluted base coat color. The dun gene may interact with all other coat color alleles.

Overo refers to several genetically unrelated pinto coloration patterns of white-over-dark body markings in horses, and is a term used by the American Paint Horse Association to classify a set of pinto patterns that are not Tobiano. Overo is a Spanish word, originally meaning "like an egg".There are at least three genetically different spotting patterns which fall under the "overo" classification: frame overo, sabino overo, and splash or splashed white overo.

White horses are born white and stay white throughout their lives. White horses may have brown, blue, or hazel eyes. "True white" horses, especially those that carry one of the dominant white (W) genes, are rare. Most horses that are commonly referred to as "white" are actually "gray" horses whose hair coats are completely white and may be born of any color and gradually "gray" as time goes on and take on a white appearance.

Sabino is a group of white spotting patterns in horses that affect the skin and hair. A wide variety of irregular color patterns are accepted as sabino. In the strictest sense, "sabino" refers to the white patterns produced by the Sabino 1 (SB1) gene, for which there is a DNA test. However, other horse enthusiasts also refer to patterns that are visually similar to SB1 as "sabino", even if testing indicates the gene is not present. Use of the term to describe non-SB1 "sabino" patterns in breeds that apparently do not carry the gene is hotly debated by both researchers and horse breeders.

A melanistic mask is a dog coat pattern that gives the appearance of a mask on the dog's face. The hairs on the muzzle, and sometimes entire face or ears, are colored by eumelanin instead of pheomelanin pigment. Eumelanin is typically black, but may instead be brown, dark gray, or light gray-brown. Pheomelanin ranges in color from pale cream to mahogany. The trait is caused by M264V (E^M), a completely dominant allele (form) of the melanocortin 1 receptor gene.

Dominant white Horse coat color and its genetics

Dominant white or white spotting is a group of genetically related coat color conditions in the horse, best known for producing an all-white coat, but also able to produce various forms of white spotting and white markings, several of which are sometimes referred to as sabino.

Roan is a horse coat color pattern characterized by an even mixture of colored and white hairs on the body, while the head and "points"—lower legs, mane and tail—are mostly solid-colored. Horses with roan coats have white hairs evenly intermingled throughout any other color. The head, legs, mane and tail have fewer scattered white hairs or none at all. The roan pattern is dominantly-inherited, and is found in many horse breeds. While the specific mutation responsible for roan has not been exactly identified, a DNA test can determine zygosity for roan in several breeds. True roan is always present at birth, though it may be hard to see until after the foal coat sheds out. The coat may lighten or darken from winter to summer, but unlike the gray coat color, which also begins with intermixed white and colored hairs, roans do not become progressively lighter in color as they age. The silvering effect of mixed white and colored hairs can create coats that look bluish or pinkish.

References

"Horse coat color tests" from the UC Davis Veterinary Genetics Lab
"Introduction to Coat Color Genetics" from Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California, Davis. Web Site accessed January 12, 2008.
(pdf) D.P Sponenberg and M.C. Weise, "Dominant black in horses" in Genetics Selection Evolution, Department of Biosciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, no 29, mars 1997, p. 403-408
J Henner, PA Poncet, L Aebi, C Hagger, G Stranzinger et S Rieder, "Horse breeding: genetic tests for the coat colors chestnut, bay and black. Results from a preliminary study in the Swiss Freiberger horse breed", in Schweiz Arch Tierheilkd, Institut für Nutztierwissenschaften der ETH Zürich, n°29, 2002, p. 144(8):405-12

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