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Horse Illustrated

10 Fun Facts About Gray Horses

Horse, Normandy, France, by isamiga76 on flickr/CC BY 2.0

We’ve talked about the allure of palomino horses and explored facts about chestnuts, but today let’s turn our attention to horses of yet another delightful color: gray. With their stunning beauty and fascinating genetics, gray horses have delighted equine enthusiasts for centuries. Let’s take a closer look.

1. Gray horses have one or two copies of the gray gene. A horse with one copy of the gray gene is said to be heterozygous for gray and can potentially produce gray OR non-gray offspring, depending on whether or not the gene is passed on. An equine with two copies of the gray gene is said to be homozygous for gray and all of the horse’s offspring will turn gray, without exception. This is because the horse does not possess a non-gray gene and therefore can only pass gray.

2. Gray can be spelled g-r-e-y- or g-r-a-y. Some breed associations prefer grey, others prefer gray. The University of California-Davis Veterinary Genetics Laboratory uses gray.


3. They can be born any color. There’s a common misconception that all grays are born black. Not so! They could conceivably be born ANY color. (It’s interesting to note, however, that when a black foal is going to go gray, it is usually born a deep, jet-black. Black foals that do not carry the gray gene are often born a mousy-gray color, which is why people sometimes joke that “black horses are born gray, gray horses are born black.”)

4. Gray is a modifier. Gray modifies the base coat color, transforming it to gray. Genetically, the horse is the color it appeared at birth, but the presence of the gray gene modifies the coat color to gray.


5. They must have at least one gray parent. The gray gene is a dominant gene and cannot “show up” later on, as recessive genes are wont to do. So if your horse is gray, you know without question that one or both of its parents were gray.

6. They keep life interesting thanks to the myriad shades of this color from “rose gray” and “dappled” to “flea-bitten” and “pure white.” It’s a transformative process that can take many years.

7. Grays are found in many breeds. The color is commonly associated with the Lipizzan breed, but it is also very common in Andalusians, Arabians, Welsh Ponies, and is accepted as a color by most breed registries.

8. Gray horses have won the Kentucky Derby on eight occasions. These famous gray Thoroughbreds include: Determine, Decidedly, Spectacular Bi, Gato Del Sol, Winning Colors (a filly), Silver Charm, Monarchos, and—most recently—Giacamo in 2005.


Silver Charm, winner of the 1997 Kentucky Derby and Preakness Stakes, now resides at Old Friends Thoroughbred Retirement Farm in Georgetown, Kentucky.

9. The only Kentucky Derby winner to be disqualified was a gray. Dancer’s Image, initial winner of the 1968 Kentucky Derby, was later disqualified after a drug test showed the presence of phenylbutazone. The disqualification remains a topic of controversy even today.

10. The Horse in the Gray Flannel Suit, the 1968 Disney comedy starring Dean Jones and Kurt Russell, features a gray horse named Aspercel.

Has your life been influenced by the companionship of a gray horse? Share your stories in the comments!

This article is a web exclusive for Horse Illustrated magazine, originally published September 2016. Click here to subscribe!

Samantha Johnson

Samantha Johnson is a freelance writer and the author of several books, including The Field Guide to Horses, (Voyageur Press, 2009). She raises Welsh Mountain Ponies in northern Wisconsin and is a certified horse show judge. She loves Corgis and shares her home with her Pembroke Welsh Corgi, Peaches.

View Comments

  • I love my gray horses. I have a big beautiful gray mare that is precious and smart as they come. She was born a blue roan and turned many shades of gray starting around 5. She is an amazing barrel and pole horse! She just had a foal 6 months ago that she transferred the roan and gray gene too. Her stud colt is amazing just like his Mom, looking to be a brown roan and continuously changing shades of roan with the seasons and he will eventually turn gray later in life as well. He only carries one copy of the gray gene.

  • Her name is Grey Goose but I call her Gigi for short. The most beautiful dapple grey quarterhorse mare you ever did see. Strong personality and the spirit to match. Fast as lightning and loveable like a teddy bear. Quick learner. That's my Gigi in a nutshell.

  • Blessed with a 7 year old mare named Pepper who is my grey beauty and a really big girl! She was born red and every year it's like getting a new horse with all her color changes. She has a black with frosting mane, black and flaxen tipped tail with an ever lightening grey coat

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