results from a genetic modifier called
The Gray Gene

Mike Kerson and Ruby, his grey Mustang mare

HOW IT WORKS: Human hair turns gray as part of the aging process. Horses who have the GREY GENE do this, too, only in horses it is not related to old age. With horses, the graying process often begins in the first year, often noticeable within the first few months.

Grey is a Dominant, requiring only one gene from one parent in order to take effect. Technically, gray is not a true COLOR gene, but rather, a COLOR-REPLACING gene.

Gray gradually replaces whatever other color(s) that may be present in a horse's genetic makeup.

Gray horses show an amazing variety of variations, in part dependent upon their "stage" of graying

This gray mare's foal is already showing signs of turning gray.

Bay foal with gray gene, showing more mature bay coloring than normal for a foal that age

First Stage:

Horses with the grey gene can be any color or color pattern at birth (yes, including pinto and appaloosa!) depending on their other color inheritance.

A horse must have at least one Grey parent to be Grey.

Since Gray is dominant, if a horse inherits one Grey gene it will be grey, and at least 50% of its offspring will be gray.

Homozygous Greys have two gray genes, one from each parent, and their offspring will turn Grey 100% of the time.

Horses who will go gray are often born at a more "mature" or darker color than would others with the same color. For instance, normal bays are born with light legs. Bays who will gray are born with darker legs.

These pinto foals have a 50-50 chance of inheriting their mother's Gray gene

"Cinnamon" owned by Nan Moore of Florida

EARLY SIGNS OF GREYING: Sometime in early life, horses with the gray gene begin to "roan" or develop a sprinkling of gray on the backs of their ears and around their eyes.

At this stage they may look like reverse raccoons, with big grey/white circles around their eyes. However, this is not dependable: not all gray horses develop the goggles look. They may be confused with  roans. Many "blue roans" are actually grays in the early to middle stages of graying.

A white area, such as a blaze on the face, may seem to "leak out" spreading and growing irregularly, like spilled milk.

"Color Precocity:

Future grays are often born at a more "Mature" stage than would a stable-colored horse of the same coloring. For instance: A bay that will turn grey is often born with black legs (which is a more mature stage than normal) whereas a normal bay foal is born with light legs that do not turn black until the first shedding - see photo at right)

A "Normal" Bay foal who will stay bay is born with light-colored legs. Compare this to the foal at left, who will turn gray like his mother.



At right: Early graying signs: gray shows first around the eyes and backs of the ears. The face turns light, too, which is not seen on roans (which these foals are often mistaken for)

Next: CONFUSING STAGE: In the early and intermediate stages of the graying process, the horse will have a mixture of white and dark hairs, a most confusing stage for trying to identify color, as it closely mimics various other patterns, such as Roan, Rabicano, Roaned Sabino, Varnish Appaloosa, etc.

Gradually the gray takes over, and the entire horse turns gray, either dappled or a flat steel gray. Eventually, most grey horses fade to pure white. (Roan, which this stage of gray is most often confused with, is not progressive, and does not involve graying on the face. In fact, lack of a solid color mask - in other words, lots of white flecking on the face - is the surest indicator of gray vs. true roan. An exception is the sabino roan, which may have even roaning throughout the body including the head. But sabino roan is not progressive.)


Rose Greys will develop from red horses; Steel or Pewter Greys will develop from black horses. Bays going gray will be a warm rosy-pewter

At this stage Greys may still be confused with Roans and Sabinos.


CONFUSING STAGE: ROANS, SABINOS, & SOME APPALOOSAS may look similar to gray at this confusing stage, but there are differences:

 l - r: Roan (note solid colored "mask" on head), Sabino Roan, Appaloosa
See the Roan page for more about this


DAPPLE GRAY PHASE: The Dapple Gray phase is the phase for which Gray is best-known. By the time the classic "Dapple Gray" phase phase emerges, it is obvious that the horse is a gray and not a roan! The extent of dappling varies considerably, however. Some horses are more of a flat gray, with only subtle dappling, if any at all. Others are wildly dappled.

Rainer Stabenow on his Egyptian Arabian gelding

WHITE PHASE: After a few years of lovely grey, often dappled, the grey continues to fade and eventually the horse will appear pure white. Some horses turn white by 6 or 7. In others the process takes much longer, with the horse staying dapple grey long into his/her teens or later. Many "White" horses are actually greys. Gray horses who turn very white are believed to be homozygous for the gray gene.

"Pure White" Gray Shire at Grass Valley Draft Horse Classic

"Pure white" Gray Shires at the Draft Horse Classic in Grass Valley, CA

Joachim Stabenow with his Polish Arabian, Gypsy

FLEA-BITTEN STAGE: Some grey horses who have faded to white will develop tiny flecks of their original color. This phase is called "Fleabitten" Grey. Sometimes these dots occur in concentrated areas, resembling an appaloosa pattern, and other times they evenly cover the entire horse.

Fleabitten grays are believed to be heterozygous for grey, meaning they have a 50-50 chance of passing the gray gene on to their offspring.

Although most grey horses have dark skin, there is a variation of the grey gene that causes the skin itself to lose pigment as the animal ages. This is sometimes called "PINKIE", and is common in the Lippizan and Arabian breeds.


All grays will turn gray the same way (over time, progressively), but the rate of fading has to do with individual genetics and body chemistry. In some horses, the mane and tail turn white before the rest of the body, while in others the mane and tail stay darker longer. It's just individual, but the end result will be the same.

This beautiful Percheron is at the steel-gray phase, still nearly black, but the mane was the first to whiten. Very striking, resembling Silver Dapples in many ways.

Our mustang, Ruby, was adopted at 7 months as a typical "Nevada Brown." We were proud of ourselves for resisting the urge to adopt for color (there were some incredibly colored buckskins and pintos in her adoption group) but rather for conformation, movement, and what for lack of a better word is "spirit" or "heart connection." We were in for a surprise. At first we thought she was a roan, then a sabino roan, and now it is clear she's a Gray.

October 2000: at adoption, labeled "Brown" on her papers.
Her mother was a bay, and in this photo we can see that Ruby is exhibiting "color precosity" - a very dark bay with black legs, at an age at wwhich normal bays would not be so dark yet.

2001: "roaning" most prominent around ears and face and starting to get a salt-and-pepper look over the entire body




Ruby at age 4, August, 2004


2006: Ruby as a 6-year-old. Similar to last year, only a bit lighter.

Ruby at 7 is still dappled, but a bit lighter than last year.

Ruby at 9, still dappled but lighter

Ruby at age 10

Ruby at age 13



In 2010, I attended the World Percheron Congress in Des Moines, Iowa, and I was fascinated by the variations in graying seen in the percherons:

Classic dapple grays

Jim Olson's fine-performing team is a pair of nearly white grays

The many Phases of Greying, exhibited by these BLM Internet Adoption Wild Horses

Color genetics are the same for all horses, regardless of breed or ancestry.



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