Why Are White Horses Called Gray?

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).

Horse Color Genetics: The Silver Gene

Review: E/e=black or red, A/a=bay or black

Dilute genes are any genes that make the horse turn a lighter color, like dun, cream, or champagne. Silver is sometimes put in the same category, but I personally don't think of it as a dilute, but more of a modifier.

Silver, similarly to agouti, only works on horses with dominant extension (E/e, or E/E). A horse must have black pigment for silver to be 'active'. It won't show up on a horse with red pigment (e/e).

What exactly is silver? A horse with black pigment and the silver gene (abbreviated with a Z) will always have a significantly lightened mane and tail, which can range from a silver color (hence the name), to a blonde or cream color. Sometimes even a bizarre orange color, like the Morgan below.

All black pigment, whether on just the legs or over the whole body, depending on whether the horse is black or bay, is usually lightened to some degree. The normal color is sort of chocolate, but it can be much darker, but not quite pure black. The one below is on the darker end. If it is a bay horse, then the whole body will not be lightened, but the black on the legs will.

Silver is a simple dominant gene, with exceptions. One copy or two dominant copies won't make a difference, the horse will look the same. The exception is a horse with red pigment will not be silver, like I mentioned before. There is a catch, and that is that red horses, or horses with recessive extension, can still carry the gene. A red horse can have the silver gene and hide it, since there is no black pigment to lighten. The pony below could carry it, and when crossed with a black or bay horse could produce a silver baby.

When paired with a black horse, it is called 'silver dapple' or sometimes 'black silver', and with bay, 'silver bay'. Basically, add on silver to whatever the color is, with the exception of silver dapple. Silver buckskins are very pretty, although unusual. Not neccesarily rare, but silver is not very often paired with other modifiers, but it is possible. The first pony is a silver bay, and the one below is a silver buckskin.

Flaxen chestnut, which can be a very dark color, is sometimes confused with silver dapple. Because a red horse can range in color from bright red to a liver color, and then paired with a cream mane and tail, the darker flaxen chestnuts are sometimes easy to mistake as silver dapple, and vice versa. However, the silver gene usually causes the mane and tail to be not nearly as white as a flaxen chestnuts. The horse below is bay roan silver.

The color has been partially isolated in particular breeds such as Rocky Mountain, Morgan, Shetland, Miniature, and Icelandic. It can also be in Quarter horses or other breeds, but is more unusual.

Horse Color Genetics: Rabicano

To Review: E=black, A=bay, C=cream, Rn=roan

The color rabicano is often confused with the modifier roan, but they are actually very different. Rabicano is a gene that causes roaning in a small area of the body, restricting the roaning section to just around the flanks.

The above horse has minimal rabicano, but the tail sort of gives it away.

Interestingly, rabicano horses usually have very peculiar tails. They are sometimes called 'skunk' or 'coon' tails. The pictures are sort of self-explanatory. The word rabicano is Spanish, 'rabo' meaning tail and 'cano' meaning white. Thus, 'white tail'. 

Horse Color Genetics: Graying Out

Review: E=black, A=bay, G=gray, LP=leopard complex, Rn=roan

I know I've talked a little bit about gray in the past, but I thought I would bring it up again after some interesting Facebook genetics topics. Several people on that forum have asked whether their foal will gray out. If one parent is gray, then there is a 50/50 chance of graying out. The main question is: how do I know if my foal will go gray eventually?

When foals are first born, sometimes there is no way to tell. Here are a couple signs that they will gray out.

Some foals will have 'goggles'. This is a fairly certain way of knowing. The little guys below have goggles.

Some foals are born with little white flecks already in their coat; I don't know if I'll be able to find any good pictures of this.

I just learned that black foals who are born jet black usually gray out, while a black foal who will stay black is sort of a mousy grayish color. Compare the black foal above, who will gray out but is very black, to the sort of dingy color of the black below.

Foal coat colors are often misleading. When they are born, that super-soft coat will often shed out to be a different shade than what they were born with. One lady I knew had a bay tobiano filly that she had really wanted to be black. She shaved her after she was a few weeks old and was disappointed to learn that she wasn't actually black underneath, but a slightly darker shade of bay. I believe most foals shed out to be a richer color than they were born with, but remember! Pinto foal's coat patterns never change, even though the base color will a little.

Here is a stumper:

I knew a mare that looked like this once, and at the time, I had no clue. But now I know better.

The horse above WAS a paint (he still carries that gene), but the color is covered up by gray. You can still see the lines where the markings are. Some will develop flea-bites (the marking, not the actual thing) in the colored areas, like the horse below. 

I don't know why, but of all the grayed-out paints I've seen, all of them seem to have a bit of a bluish tint to the color areas. Especially in the first one.

Horse Coat Colors: Roan

Roan is a modifier, or a color shifter, kind of like pinto or appaloosa. It causes the base coat to be evenly mixed with white hairs, lightening the original color. Roans generally have darker manes and tails, darker heads, and dark legs. White 'normal' markings on the face and legs are acceptable.
Some roans have little dark spots. This doesn't mean that they have the LP gene. It is simply a spot that didn't get covered up by white.
Roan is a simple dominant: whether the horse has one or two dominant copies is irrelevant unless you are breeding and want to know. The following pictures there isn't any way to tell if they are homozygous or heterozygous unless you look at their parents or offspring.
A blue roan is a black horse with the roan gene. Sometimes they look a little silvery.

A red roan is a chestnut horse with the roan gene. Sometimes they are called 'strawberry' roan. Please know that there is no difference. In the past, bay roans have also been red roans, but this is not technically correct.

A bay roan is a bay that has the roan gene. Easy. None of these are hard to remember, but honestly, if we just called them black, chestnut, and bay roan, wouldn't it be easier? The first horse isn't a very even roan, but she is still bay roan nonetheless. That second one down may look like a blue roan, but the color of the head gives it away.

And lastly, there is palomino roan. These aren't very common, which is kind of weird (I don't know why). They are sometimes called 'honey roan'. 

And that concludes roan! What is nice about roan is it is easy to identify, and the base color is easy to spot.

Horse Color Genetics: Gray

So now you have the basics down! Review: E = black, A=bay.
If all horses are really chestnut with different colors added on, then how do you explain white horses?
For white horses, it is important to understand that white horses are not really white at all. When people refer to 'gray' horses, this usually means a horse that looks white, but in fact their skin is a different color.
Gray horses are born a different color (usually dark bay or black), but inherit a gene from one of their parents that causes them to turn white (or the technical term is gray) as they get older. The gray gene is a dominant one, meaning that if any horse is  heterozygous or homozygous dominant (one or both genes being dominant) it will effect any color horse the same way.
Truly white horses are really, really rare and actually are born white. That is a different topic, but horses born pure white are called 'dominant white'.
The symbol for gray is G; any color horse who inherits either one or two of these genes will turn white, no matter the color. Here is a gray horse:

Again, even with grays, the trait can be either homozygous or heterozygous. If they are heterozygous, then their foal may or may not turn gray with age, there isn't really any way to tell right away unless you test them genetically.
Some gray horses don't turn white all the way; some remain in a state in-between. This color is referred to as 'dapple gray'. It is a color, but they still carry the gray gene. Their genetic code is still the same, or they may still turn lighter, or they could stay like this forever. The amount of graying cannot be determined.

Here is an example of a gray horse's color code: Ee, aa, GG (I'm just making this one up). This horse was born black (I know it was black and not bay because both of the a's are recessive), but will most certainly gray in time because it inherited dominant gray genes. And because this horse is homozygous gray, it's children will most certainly gray as well. You only need one dominant gene for the gray effect to happen. Another code is Ee, AA, Gg. This horse was a bay, but will gray in time. You see? Gray is a more simple concept to understand compared to some of the others.
Sometimes gray horses that turn pretty light will develop little tiny flecks that look like freckles. They can be all over the body, fairly large flecks, or in just one area. This is called 'flea bitten gray'. It is not a genetic thing that can be inherited, it just happens. The color of the flecks depends on what color they were before they turned gray. Black horses turned gray that develop flecks will probably have grayish flecks, while the horse below might have been chestnut or bay because they are brown.