Any equestrian has experienced the average pedestrian commenting on the pretty white horse out in the pasture or in the arena. Here it comes: the eyeroll, the sigh. "It's called gray, not white." Every equestrian knows that. Duh! However, the embarrassing question of "why" comes and you realize that the question is completely legit. And you don't know the answer.
OK, so most equestrians know that most white horses are called gray, even if they don't know why. Some people like to get technical and specify what kind of gray the horse is: dapple gray, iron gray, rose gray, flea-bitten gray. Whatever. None of those are helpful or relevant, and don't answer the question. Here is the logic behind the fact:
Gray horses are born with the gene called- well, gray - and is abbreviated with a G. What the gene does is it slowly adds more and more white hairs to the horse until it turns completely white....or mostly white. This is called de-pigmentation. Every horse that turns gray does so at a different pace. There are many stages of gray, and each stage looks a little different. The technical terms mentioned earlier are not relevant because gray is a progressive color. Each stage might be permanent, or not.
When gray horses are born, they look like any ordinary foal. Cute, and not white. The gray gene (G) is inherited seperately from other color genes, and gray is not a color by itself. Instead, it modifies and changes an existing color that is already there.
Photo contributed by Katy Heck Anderson
Photo contributed by Giorgia Guzman Lucatti
The next stage: as the horse gets older, more and more white hairs cover the body. Some horses go through a bit of a hyper-pigmentation process, turning their original foal color to something darker, usually a weird shade of dark gray, or appear a bit like a roan because of all the white sprinkled throughout their body. The horse below is the same as the foal in the above picture, at 8 months.
Photo contributed by Giorgia Guzman Lucatti
The dapple gray stage is kind of dicey; some horses remain dapple gray for the rest of their lives, and for some it is very fleeting. A dapple gray is when the horse is mostly covered in white hairs, with some dark shades showing through. Some horses that were originally a red color (chestnut, bay, palomino, etc.) might be reddish in color. Some people like to call those "rose grays", although I prefer to avoid being over-technical as it really doesn't matter. The horse is still gray.
Photo contributed by Kari Topjian-Cohen of Dipity Dew
Photo contributed by Jenna Chasnov
The "finished" gray stage is when the horse has turned completely white. Some horses take a long time to turn completely white, and some don't turn all the way white at all and stay in the dapple stage. This is the most commonly mistaken phase that a horse will be called white because, well, he is.
Photo contributed by Ashley Gerrard
Photo contributed by Johna Racquel Pink
Another very common stage of graying that many horses go through is called flea-bitten gray. Genetically, no one knows why it happens. It usually happens after the horse has turned completely white, although some horses begin developing flea-bites while they are still in the dapple gray phase.
Photo contributed by Heather Kaplan
Some individual breed peculiarities:
-Percherons tend to have an incredibly slow de-pigmentation rate, and typically stay in the dapple gray stage most of their lives. Percherons also do not usually develop flea-bites.
Photo contributed by Lauren Zimmer
-Arabians have the highest tendency to be flea-bitten, and also are known for having the most dramatic dense flea bites than any other breed, although any horse regardless of breed can develop flea-bites. Sometimes they can be so dense the horse almost looks like it is re-pigmenting.
Photo contributed by Melissa Rose Obermann
-Color breeds such as Paints and Appaloosas can also be gray, but because the gray covers up the coveted unique color the individuals are less desireable in breeding programs. The horse below is a grayed-out paint.
Photo contributed by Cassidy Allison
Now, not all white horses are gray, but it is by far the most common white horse color. Other white horse colors include double cream (always have blue eyes), maximum sabino (white with pink skin and dark eyes), and dominant white (same as maximum sabino).
