Horses have many definitions regarding their coat colors, and the bay color is one of them. However, determining what is a bay horse isn’t as easy as it seems because they vary in color.
What is a bay horse? A horse is referred to as bay if the coat color is either reddish or brown. The tail, mane, ear edges, and legs can have black color. These colors are standard; it’s just that most horse lovers don’t know how to define them.
Though bay horses primary definition is reddish, brown, and black colors, they vary depending on genes. You should not misinterpret Bay color as a breed but only a color pattern.
What is the Color Genetics of a Bay Horse?

Besides colors, bay horses also have varying patterns, shades, and appearances. It’s only the genes that don’t defer.
Bay color is a base color in horses. Researchers confirm that the agouti (the suppression gene) and E allele gene (the extension gene) are behind these dormant colors. Both genes are necessary for a bay horse; otherwise, one gene cannot create a bay horse.
All horses have the allele genes that form the pigment in horse coats. But the one that makes bay horses unique is the agouti gene. In a rare case, there may be an additional gene during breeding. As a result, it alternates the color pattern.
The E Allele Gene produces Melanocortin that forms the black spots in horses. This gene is usually of two types; E/e or E/E. A bay horse should possess one of these.
Therefore, if you encounter a bay horse without black sports, either of the E allele genes is missing. You will note that the coat color is red, and that is not a bay horse!
On the other hand, the Agouti gene produces ASIP(Agouti Signalling Protein), which ensures that the black marks don’t attach in one spot. If the gene is dominant, then the horse will only be of red and black coat color. It’s referred to as a standard bay horse. But if the gene is not dormant, then the red color will be missing.
Since the agouti gene only forms the black colors, it can’t fully control the genetic characteristics. But it does on other horses like chestnuts.
Bay Horse Shades
The reason why bay horses have different patterns is additional genes to the primary ones. Here are shades that bay horses explaining the variations in colors.
Black Bay
Black bays have dark bay color. The muzzle and flanks are brown. Most horse owners find it challenging to determine a black horse and a black bay horse. Only a DNA test can characterize the two since a black bay has the Agouti gene.
Wild Bay
It’s challenging to distinguish a standard bay from a wild bay. Wild bay horses also have reddish coats with black manes, tails, and legs. The only difference is that the black markings on the wild bay legs don’t exceed the knees and their muzzles are either white or light-colored.
Dark Bay
This horse has a dark brown coat and black and white spots on the legs. Their tail and mane can either be light-colored or share the same pigment. It’s almost similar to a liver chestnut, except that it has no black markings.
Brown Bay
Distinguishing a brown bay from a brown horse is quite a task. The good thing is that all bay horses have black spots in the manes, legs, and tails. But if the horse does not have the black markings, that’s a chestnut!
Mahogany Bay
Mahogany bay horses usually have dark reddish-brown coats. They also have black markings.
Standard Bay
The coats of Standard bay horses are usually brown or red with some black spots. It’s the most common shade in bay horses.
Sandy Bay

The coat of Sandy bay horses is light-colored and also possesses black markings. This light-coloring is a result of a different cream gene. The yellow coat color makes them look like buckskin.
Blood Bay
It’s one of the darkest colored horses. The coat of a Blood bay horse is usually bloody red. Sometimes they seem to have a purple shade due to the deep pigment. Most people mistake them for Standard and Mahogany horses. However, it’s a rare color.
Golden Bay
Golden bay horses, also known as Light bay, are the lightest and rare bay shade. The coat can have either have a golden yellow or a light red color. They are almost similar to dun, buckskin, and sandy horses.
Copper Bay
Copper bay horses are similar to Standard bay horses. However, they have lighter shades, just like copper. Their coat color is orange-red.
Buckskin Bay
Buckskin bay horses have orange, yellowish, or cream coat colors. They vary with dark and light colors, but all their eyes are dark-colored. Most of them possess a gene that forms a cream dilution.
Perlino Bay Horse
Perlino horses have cream coats. They possess two genes that form the cream dilution. Their eyes are blue and pinkish skin, traits that people misinterpret as albinism.
Perlino bay horses were not allowed to register until 2000, when the American Quarter Horse Association acknowledged them.
Bay Dun Horse
Bay Dun horses have light yellow or tan coat colors. They possess the bay dun gene, which explains the dorsal spots on the legs. These horses resemble the zebra due to a dark stripe at the back center.

Bay Roan Horse
Bay Roan horses have bay coats with white hairs. They might have little or no hairs on the legs, mane, tail, and head.
These horses may have light or dark coats depending on the seasons due to the roan gene leading to varying patterns.
Bay Pinto Horse
Bay Pintos have white spots, similar to some cow breeds. The areas look like human art since they form artistically. This attribute is due to a white spotting gene that causes variations in patterns.
Silver Bay Horse
Silver Bay horses have a silver gene contributing to the chocolate coats and manes and tails with faded colors. Sometimes the skin may appear gray or brown dilution.
Bay Leopard Horse
Just as the name implies, their coat resembles a leopard’s pattern. They have brown dotted spots on pinkish or unpigmented skin. The spotted pattern is more concentrated on the eye and muzzle area, making it dark brown.
Amber Champagne Bay Horse
Amber Champagne bay horses are spectacular in their brown eyes, chocolate spots, and golden coat. They possess a champagne gene that forms a golden pigment from diluting red and dark brown colors.

Horse Breeds that Have Bay
Bay horses are wildly acknowledged for registration since it’s a standard color. But in some cases, some breeds possess a single color. There are horse breeds that have more than one color and have higher chances of maintaining bay colors. They include:
Morgan
The Justin Morgan horse has maintained its dark bay color throughout the centuries. Besides bay, they also have various colors such as buckskin, dun, palomino, gray, chestnut, brown, and black. However, the gray color is rare.
Warmblood
Warmbloods mainly possess solid colors like chestnut, gray, brown, bay, and black. A few of them can get the bay color. They include Trakhener, Selle Francais, Oldenburg, Holsteiner and Dutch Warmblood.
Canadian Horses
Canadian horses are believed to be the descendants of Morgan horses. Most of them are black bay, while others are chestnut but rare. Their tails and manes are flaxen.
Clydesdale
Clydesdale horses are suitable for war since they are capable of carrying heavy things. Most of them have bay colors, while the rest have chestnut, brown and black colors.
Besides the deep bay color, their legs have white hair covering. The bay color has made Clydesdale horses famous for appearing in TV commercials in the United States.
Standardbred
Standardbred horses are famous for harness racing. Even when a bay Standardbred horse has retired from racing, you will find them being driven or for pleasure. The reason is that they are demanding in the racing industry.
These two-centuries-old Standardbred horses usually have black, brown, or bay horse coats.
Thoroughbreds
Thoroughbred horses are the best in horse running, and the famous ones like Barbaro, Northern Dancer, Seattle Slew, American Pharaoh, and Seabiscuit were bays.
The colors in Thoroughbred are followed keenly during registration. Before registration, the foals must undergo DNA testing.
Hackney
Hackney ponies and horses are best for driving. They hold solid colors, bay included!
Marwari
Marwari horses descended from India. They hold metallic bay colors.
Arabians
Arabian horses have bay colors. However, there is an exception of perlino and buckskin since they are diluted. Most horses have black coats to endure the desert sun.
Can the Bay Color Affect the Health of a Horse?
Horses can live up to four decades. However, any horse breed is prone to health problems. In addition, coat colors also impact the horse’s genes. Bays like the bay leopards, bay pintos, and silver bat are prone to such abnormalities.
Here are the gene abnormalities that affect each of them:
CSNB
Congenital Stationary Night Blindness is common in Bay Leopards because they possess two leopard genes.
CSNB causes blindness in eye cells that are responsible for detecting light. Therefore, the horse can’t see in dimmed lights.
OLWFS
Overo Lethal White Foal Syndrome attacks Bay Pintos with overo patterns. A horse with this condition can pass it to its offspring. The foal can neither eat nor excrete and eventually dies.
ASD
Anterior Segment Dysgenesis attacks horses carrying the silver gene. These types of horses are mostly the Silver Bay horses and the Rocky Mountain breed. It affects the lens, cornea, and iris parts of the eyes. As a result, the eye pupil malfunctions.
Are Bay Horses Expensive?
A breeder can sell a horse between $2,500 and $7,000. However, there are breeds with higher prices, up to $25,000. Bay horses from Thoroughbreds, Quarter horses, and Arabian are more expensive.
Final Verdict
Bay horses are either dark or light-colored. The primary checkpoints are the lower legs, tails, manes, and ear tips to determine a bay horse. However, DNA testing is more accurate to check whether the horse carries the agouti gene.
Although they have unique shading, they are some of the most beautiful horses in the world.