What Are Ergots And Chestnuts On Horses? 

September 11, 2022
ergots and chestnuts on horses

Ergots And Chestnuts On Horses have been depicted throughout history (and in modern times) as majestic, beautiful animals that sport lush flowing manes and shiny coats. However, they also have these unsightly growths, which occur and can be found on a horse’s legs in various locations. What are they? Do they have a function? Can they be removed? Let’s find out.  

Ergots And Chestnuts On Horses are callus-like growths made of living tissue. Chestnuts appear above the knee (foreleg) and below the hock (hindleg), while ergots are found on the fetlock. They are believed to be a remnant of some foot part that has long disappeared due to evolution.  

This article will dive deeply, going over in detail what are ergots and chestnuts on horses, how common they are if they are all the same, why horses have them, whether can they be removed, whether will they affect a horse, and more. Everything you ever wanted to know about these protruding growths can be found here, so read on to find out more.  

ergots and chestnuts on horses
The hooves of a horse running through send

What Are Ergots And Chestnuts On Horses? 

Chestnuts, also known as “night eyes” (due to urban legend), are patches of living tissue forming calluses found on the back of a horse’s foreleg above the knee. Additionally, they are also found on a horse’s hindleg below the hock.  

An ergot (similar to a chestnut) is another patch of living tissue forming a callus on a horse’s legs. However, these, in particular, are found on the fetlock above the pastern.   

Do All Ergots And Chestnuts Look The Same? 

In terms of ergots and chestnuts on horses found on horses, they can vary dramatically from horse to horse. As such, chestnuts are unique to each horse and can be thought of as a fingerprint. 

In some cases, chestnuts stay smooth throughout a horse’s life, while in others, they are found to be jagged and rough. Moreover, this callus-type tissue may even grow, stack up, and thicken over time. 

For ergots, the visual appearance is similar to that of a chestnut. This means that they can either be rough or smooth and protrude from the fetlock (grow and thicken) over time.  

Ergots and chestnuts on horses

How Big Are Ergots And Chestnuts? 

Chestnuts will vary in size and shape from horse to horse. Additionally, chestnuts may vary in size and shape on each leg of an individual horse.  

Ergots will range in size from small (being the size of a bean or pea) to up to several inches in length (approximately 1.5 inches in diameter).  

Consider that while many horse breeds may have ergots, as with chesnuts, they will typically be found to be the largest size in horses with feathers (long hairs that extend past the fetlock). 

Do All Horses Have Ergots And Chestnuts? 

Chestnuts are found on all four legs for the majority of domesticated horses, along with the Przewalski’s horse (the last known “wild horse” breed); however, some domestic horse breeds will lack chestnuts on their hindlegs.  

Moreover, chestnuts are absent in wildlife Equidae such as zebras and asses (donkeys). 

While chestnuts are found on most (if not all) domesticated horse breeds, ergots may be present or absent (may or may not appear) on some or all legs of a horse, depending on the breed.  

Field of horse and jockey during a race

Why There are Ergots And Chestnuts On Horses? 

Ergots and chestnuts are believed to be the remnant (vestige) part of a multi-toed Equidae (the biological term for the classification of horses) that has come about due to evolution. This means that scientists once thought that ergots and chestnuts were additional parts of a horse’s legs that were not utilized, and thus due to the consequences of evolution, they disappeared over time.  

Consider that chestnuts can be related to vestigial carpal and tarsal pads, while ergots can be considered to be rudimentary metacarpal and metatarsal pads.  

To understand this a bit more, it would help if you understood that carpal bones are found in the hands of humans while tarsal bones are found in the feet. We can correlate this to horses having carpal bones in the foreleg and tarsal bones in the rear leg.  

Now three sections make up the hand and feet, and these are namely; 

  • Carpal or tarsal (the first section) 
  • Metacarpal or tarsal (the second section) 
  • The digits (the third section) 

In all instances, animals with four legs (cats, dogs, bears, and in this case, horses, etc.) typically have this bone structure making up their legs and feet (their limbs) in one way or another.  

How the bone structure is arranged is not important here but rather the concept that all animals that have feet, hands, or four limbs have this. Moreover, depending on the animal and how they walk and run on all four limbs, these sections may or may not be used and may vary in size. 

For example, bears utilize their entire paw to walk and run and thus, will use and have all three sections (with carpal sections and digits found in the front limbs and tarsal sections and digits found in the back limbs). Due to the fact that bears run “flat-footed,” both the first and second sections of their paws will be large and prominent. 

However, if we take a look at cats or dogs that walk and run mainly on their toes, they will have a small or absent first section (carpal and tarsal section). 

Now, scientists believe that due to how horses walk and run, these sections (that we stated above) were not utilized or needed. Hence, because of this and evolution, they eventually disappeared and became what we know today as ergots and chestnuts.  

Take into consideration that this is just a hypothesis that has been formulated, and there are no conclusive facts to back up this theory.  

Can You Trim Or Remove Ergots And Chestnuts on Horses? 

Keeping a horse groomed (especially for show horses) is a priority to most owners. As such, the question to ask is whether or not ergots and chestnuts can be removed or at least groomed.  

In most cases, you are able to trim ergots and chestnuts because they are essentially just calluses. Keep in mind that you do not have to and that if you do, you should never go as far as to trim or remove them deeper than the skin level.  

You will only need to peel them off layer by layer using your fingers to remove them. You could also opt to use a knife or sharp instrument that won’t hurt the horse. However, pinching them and not twisting them with your fingers should be sufficient enough.  

For the most part, chestnuts can be removed this way, while ergots don’t necessarily need to be trimmed or removed at all. This is because they are usually very small and barely visible. Although, they can be removed in a simial fashion to chesnuts if they are large and get caught on fences.  

Will Removing Ergots And Chestnuts Harm A Horse? 

As we stated, these callus-like tissue growths play no important role in a horse’s anatomy and are, for this reason, purely cosmetic. This means no harm will come to a horse that has these trimmed or removed, and they will function as normal.  

What If Ergots And Chestnuts On Horses Are Hard? 

In some cases, ergots and chestnuts on horses can be quite difficult to remove because they can become tough and hard. In these instances, it would help to know that they are much easier to remove when wet.  

If this does not work, then you can soften them by applying baby oil or petroleum jelly for several days until they become soft enough to peel away.  

Consider that if you peel or remove a chestnut or ergot’s “dry layer” (below the skin), that area will probably start to bleed. Thus it is essential to only remove the soft tissue layer, leaving the dry layer intact.  

Horse in a training field


We discovered that ergots and chestnuts on horses are callus-like growths that occur on most domesticated horse breeds and can vary in size and shape; however, you may or may not find them in some instances on horses.  These growths are believed to be part of a horse’s feet that have long disappeared due to evolution, and these are all that remain.  

Whether or not you find these growths unsightly or it does not really bother you, In most instances, they are easily removed with your fingers and are purely cosmetic, meaning that they can be removed and will not impact the horses’ behavior or anatomy in any way.  


What Is A Horse Chestnut or Horse Ergot 

Why Do Horses Have Chestnuts and Ergots on Their Legs? 

What Are Chestnuts and Ergots on Horses? – Horsey Hooves 

Chestnuts, Horse Anatomy Wiki


I'm Bo, the owner of Smarter Horse. Helping horses be smarter by educating their people.  To find out more about me, click here

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