In A Nutshell
A red horse is a red horse, right? There’s actually a variety of different types of coat colors that are applied to horses that might look very similar at first glance. A red roan is a horse that has white hairs mixed throughout the red. A sorrel horse is one that has a completely red base color and the possibility of white markings, while a chestnut horse is a much darker, brownish-red.
The Whole Bushel
Determining the correct term for a horse’s color just based on appearance can be surprisingly difficult. Chestnut, sorrel, red roan, chestnut roan, bay roan . . . they’re all terms used to describe horses that have a reddish or reddish-brown appearance. So what’s the difference?
The easiest way to describe a sorrel horse is one that is a “true” red. A chestnut horse can often have a wine-colored appearance, or look brownish-red, while a sorrel is simply red. The red can be any shade, whether it’s pale red or dark. Most have the same color throughout their body, mane, and tail, with no other markings (save occasional white on the face or legs). A sorrel horse can, however, have a blonde mane and tail, but if there are black markings anywhere on his body, that horse would then be considered chestnut.
Chestnut is another color that can be most basically described as red. A chestnut horse is usually darker than a sorrel, and includes horses that have a brown tint. The mane and tail can be the same color as the body, or blonde as in a sorrel horse. A red horse with a mane and tail that is so dark as to appear black is considered chestnut. It’s important to note, though, that a chestnut horse doesn’t have the genetic makeup to sport a black mane and tail; the appearance of such is only due to a very heavy red coloring that may make it appear black when placed against another color.
A red roan horse is one which has either a sorrel or chestnut coat that is interspersed with white hairs. “Red roan” is the generic term, “chestnut roan” or “sorrel roan” are more specific terms based on the guidelines for deciding if a horse is sorrel or chestnut. In order to be considered a true roan, the horse must have white hairs through their entire coat. Some horses only show the roan pattern by their tails and across their bellies, a pattern more accurately called “rabicano.” (A true roan may also show the white hairs only across their back.) If a true roan horse loses a patch of their coat, the hairs will not grow back white—they will only grow back as the color of the base coat.
If all that wasn’t confusing enough, don’t forget that a young horse can be a completely different color than he will be once he loses his first coat. A foal who looks grey when he is born might be red once he matures.
Genetically, a sorrel horse and a chestnut horse are the same. The gene that gives them their red coloring is a recessive gene, making it necessary for the horse to have two red genes in order to show as red. The presence of any other color gene would override the red; because it’s a recessive color, two red parents will always have a red offspring.
When a specific color gene is paired with a roan gene, that makes a red roan, chestnut roan, sorrel roan, or any of the other types of roan, such as blue.