Chestnut (horse color)

Chestnut is a common hair coat color seen in horses. It gives the horse a reddish-to-brown coat, and the mane and tail are the same color or lighter. True black hairs are never present in chestnut horses.

Chestnuts often have dark brown eyes and black skin. Their coat can range from very light to very dark, sometimes looking almost black. Unlike bay horses, chestnut manes and tails are never truly black. Some chestnuts may have pink skin with white hair in certain areas, and if white markings cover an eye, that eye might be blue.

This coat color is produced by a recessive gene. In some breeds like the Suffolk Punch and Haflinger, all horses are chestnut. Other breeds, such as the American Belgian Draft and Budyonny, are mostly chestnut. Even in breeds usually bred to be black, like the Friesian horse and Ariegeois pony, chestnut foals can occasionally be born.

Visual identification

See also: Equine coat color

Chestnut horses have coats that range from light red to dark brown. Their manes and tails match the color of their bodies or are a bit lighter. These different shades are all called "red" by scientists who study horse colors.

• A basic chestnut or "red" horse has a solid copper-red coat, with a mane and tail close to the same shade as the body.

• Sorrel is a term used in America to describe red horses with manes and tails the same shade or lighter than the body coat.

• Liver chestnut or dark chestnut are terms for very dark-reddish brown horses. These are not a separate color but just a darker shade of chestnut. The darkest chestnuts, especially in Morgan horse breeds, can look almost black. You can tell them apart by looking for small amounts of reddish hair on the lower legs, mane, and tail, or by DNA testing.

• Flaxen chestnut and blond chestnut describe horses with manes and/or tails that are much lighter than their body color, sometimes even near-white or silver. Haflingers are always this shade. Some flaxen chestnuts can look like palominos and have been registered as such.

• Pangaré or mealy is a trait that gives horses pale hairs around the eyes and muzzle and a pale underside. Haflingers and Belgians are examples of mealy chestnuts. The flaxen trait is sometimes linked with pangaré.

Chestnut family colors

Chestnut is a base color for horses, and other colors come from changes to this base.

• Palominos start with a chestnut base but change to a golden shade because of a special gene. Palominos look different from chestnuts because their coats lack red tones and have gold instead. Their eyes are often a lighter amber compared to the dark brown eyes of chestnuts.
• Cremellos also begin with chestnut but have two copies of a gene that gives them a cream-colored coat, blue eyes, and light pink skin.

• Red duns have a chestnut base with another gene that creates a pale, dusty tan body color with a dark red stripe along the back, plus a red mane, tail, and legs. They may also have extra markings that set them apart from chestnuts.
• Gold champagnes start with chestnut and have a gene that makes them look like palominos or an all-over apricot shade. They can be told apart by their amber or green eyes and lighter skin with freckles.
• Red or "strawberry" roans have a chestnut base with a gene that creates a roan pattern.
• A skewbald, "chestnut pinto" or "sorrel Paint" is a pinto horse with patches of chestnut and white.

When several genes mix together, the names aren’t always the same. For example, "dunalinos" are chestnuts with both a special gene for a dun look and another gene that lightens the coat.

Chestnut mimics

Bay horses also have reddish coats, but they have black manes, tails, legs, and other areas with darker color. This black coloring means they are not chestnut.

Seal brown or dark bay horses are also not chestnut but can look similar. People often call many horses "brown," including chestnuts. True brown horses always have black points, which helps tell them apart from chestnuts. Sometimes liver chestnuts are called brown or "seal brown" by mistake.

Silver bay horses have bodies that are chocolate to red-brown with lighter manes and tails. Their color and lack of obvious black points can make them look like chestnuts. Silver dapple horses may show hints of darker color at the roots of their manes and tails. Some flaxen chestnuts also have silver-like streaks. Genetic testing can help figure out the true color.

Inheritance and expression

See also: Equine coat color genetics

The chestnut or sorrel color in horses, called "red" in genetics, is caused by special traits in one of their genes. Horses have two copies of this gene. If both copies are special traits, the horse will have a red coat. If at least one copy is not a special trait, the horse will have a bay or black coat instead.

Because this red color is hidden unless both parents pass the special trait, two bay or black parents can sometimes have a chestnut baby. However, two chestnut parents will always have chestnut babies. This special trait stops the horse from making black pigment, so only red pigment is made, giving the horse its red coat.