What makes a chestnut horse a chestnut?

I have written about roans, palominos, bays and Appaloosas and today I thought I’d add to the collection and talk about chestnuts.

Chestnuts are generally easy to spot with their reddish-orangish-brownish coats but once in a while, you’ll come across a horse that appears neither chestnut nor bay. It’s such a quandary when this happens that there are specific features used to deduce a horse’s color.

The first is looking for black hairs because chestnuts do not possess such a thing, no matter their hue. Any black hair on the face, legs, mane or tail will turn that horse into a bay. The second key feature of a chestnut is that their mane and tail will match their coat color, with the exception of a flaxen, of course.  

Chestnut vs. Sorrel

The word chestnut tends to be used within the English disciplines while the word sorrel is used within the Western disciplines. The reason for this is that some breed associations such as American Quarter Horse Association and Belgians Draft Horse Corp view chestnuts and sorrels as different colors. These associations and likely others state that chestnuts are darker and sorrels are lighter.

The word sorrel has been around since the 1300s. Back then there was only one ‘R’ in the word, at some point we were compelled to add another. The word comes from Old French meaning “yellowish-brown,” which fits rather well with how we use the word today.

Now, the word chestnut has been around since the 1500s but in reference to trees and the nut that comes from said tree. As with the word horseradish, it’s believed that the word horse was added to chestnut due to the large size of the nut.

And while the nut may have little to do with horses it’s thought the horse color is derived from the color of the nut. Nut first, horse second.

Water chestnuts. ©dreamstime

Liver Spots

I figured this term had something to do with the liver, and in a way it does. Once you reach a certain age, as I most definitely have, you’ll find, with a sense of dismay, “liver spots” dotted around areas of your skin that have seen too much sun. They are also referred to as age spots, but there is no need to delve into that.

The technical name for these spots on humans is lentigines or lentigo if you are lucky enough to only have one. They were given the name liver spots because it was once believed, many moons ago, that the spots were a sign of a defunct liver, which, of course, is untrue.

Some horses have liver spots though it’s most common on chestnuts and palominos. These dark patches of hair are also called “Bend Or spots.” This is the first time I’ve encountered the term but apparently, there was a racehorse 100 years ago called Bend Or that had a few of these spots and so the name carried forth. Other names include smuts and grease spots.  

Liver Chestnuts

A darker reddish-brownish color leaning away from the orangish tone.

The liver chestnut name may have come about due to it being a similar color to liver spots and/or the actual liver. It’s hard to know and no one seems to be able to accurately point to one reason over another. So, we’re left in a position of assumption, which I dislike.  

Flaxen Chestnut

You might hear someone say, “Rebecca is a flaxen-haired beauty,” and they’d be correct as I do have blonde hair. This sort of hair color reference has been around since the 1500s and does indeed stem from the color of flaxseed.

But the reason why some chestnuts are blessed with the crowd-pleasing flaxen mane and tail is all down to genes, much as my hair color is.

Some breeds carry the flaxen characteristic such as Haflingers, but for the rest of the chestnuts out there where this is not a breed feature, it’s believed that the flaxen influence stems from multiple genes passed down from parents to the offspring.

Now, chestnut parents will always produce a chestnut foal, and if those parents are flaxen well then, the foal will be as well. But here is the interesting thing, bay and black horses can also carry the necessary genes to produce a flaxen offspring even though they themselves show no signs of flaxen accessories. It’s all very complicated.

Then, of course, there are varying shades of flaxen, or those with lighter manes and darker tails, which boils down to more gene stuff. But with the use of words like alleles, phaeomelanin and Mendelian inheritance or letters such as FfFf,eea and E+ I think I’ll leave the rest of this to the professionals, who say more research needs to be done to better understand why some horses are born as flaxen-haired beauties, while others are not.


That’s chestnuts for you. Admittedly, I had never put much thought into the colors of horses, but I had always wondered why the use of the word liver when referencing that one particular shade. I’m so pleased that was something I was unable to answer.

Onto the next.