A chestnut horse, also known as a sorrel horse, is a type of horse that is usually reddish in color. There are several variations on chestnut coloring in horses, ranging from almost white to almost black. Unlike truly white, black, or palomino horses, the chestnut horse's tail, lower legs, and mane will either bear white markings, or will be colored the same shade as the rest of the horse's body. The chestnut color variation is generally carried on a recessive gene, such that two chestnut horses bred together will almost always produce offspring that is chestnut in color. The gene's recessive nature, however, can mean that even horses who aren't considered chestnut in color can bear the gene for the coloration, and produce chestnut-colored offspring if bred to the right mate.
Some people refer to chestnut horses as sorrels, which is simply another name for the type of coloration commonly called chestnut. Some people refer only to lightly colored chestnuts as sorrels, or blonde sorrels as they are sometimes known. There is a type of chestnut horse that has a brown fur coat, white markings on its face and lower legs, and a whitish mane and tale. Some people refer to this type of horse as a sorrel, while reserving the term chestnut for solid-colored chestnut horses.
There are a wide range of variations in color associated with the chestnut horse type. A brownish or reddish horse with a very pale tail and mane is often called a flaxen chestnut. The lightest chestnuts are almost white on the body, with the hair of the tail and mane generally even paler. The darkest are so dark brown they almost appear to be black. These are not generally considered true black horses, because the coat, mane, and tail usually bear a reddish tinge.
Many chestnut horses are extremely reddish in their coloring. These are typically known as red or cherry chestnuts. Lighter shades are often known as sorrel, light chestnut, or honey chestnut. A standard chestnut horse is usually colored a few shades darker than the bright coloration of the red chestnut horse. Liver or chocolate chestnuts are often very dark in color, with black chestnuts considered the darkest color variation.