Horses have Night Eyes, Extra Toes, Vestigial Glands on Their Legs — or Do They?

On their legs, horses have growths that are thought to be extra toes, vestigial glands, and night eyes, which some claim help them see in the dark.

Most horse enthusiasts are aware that horses have chestnuts, but fewer are aware that they also have ergots on their legs.

Some people believe that ergots and chestnuts are both vestiges of Eohippus's pre-evolutionary legs and feet. The term "vestigial" designates something that has evolved past its original function.

Chestnut

A chestnut is the thicker, fleshier growth that appears just below the inside of the hock on a horse's hind legs and above the knees on their front legs.

They are sometimes referred to as "night eyes."

Along with other theories like the Earth being flat, it was once believed that this was how horses saw at night.

Like human fingerprints, each horse's chestnut is unique in its shape and makeup.

While the chestnut on some horses barely grows at all, others grow quite rapidly and can be peeled and even sometimes trimmed back for a more attractive appearance.

Some horses even chomp on and trim their own chestnuts.

Horse owners and groomers should use caution when grooming them because they are flesh-based growth and are sensitive to the layers closer to the horse.

For some equine cousins, such as donkeys and zebras, only their front legs have chestnuts on them.

According to IFLScience, the good news is that, despite their unappealing appearance, horse chestnuts developing on legs pose no health risks.

They are harmless growths that typically disappear on their own.

Horse owners sometimes help remove them by using oil, and as some TikTok videos demonstrate, they also like to feed them to dogs.

Ergot

The ergot is a much more minute, callous-like growth that appears on the backside of a horse's fetlocks and is about the size of a pea.

Once more, not every horse has all four.

While some breeds tend to have barely any ergot growth at all, others exhibit more pronounced ergots.

They appear to be more common on horses that have feathers. Ergots can also be peeled if necessary and are sensitive in areas where they are closer to the horse.

It's interesting to note that the word "ergot" derives from the old French word "argot" for a rooster's spur.

The spurs on the back of a rooster's leg are similar to where ergots grow.

Purpose-Driven Chestnuts and Ergots

Each horse has distinctive chestnuts and ergots that can be used to identify it.

It is known that some horses scratch and rub their faces with the front chestnuts, which are believed to be a type of scent gland akin to those on llamas.

These growths have a strong, "horsey" smell that can be detected upon closer inspection through smell.

An old cowboy trick involves putting a chestnut horse in the rancher's pocket, which causes other horses to suddenly show a lot of interest in the rancher.

The associated ergot ligament, which connects to the lower pastern, uses the ergot as an anchoring point.

Additionally, it is believed that the ergot serves a similar purpose to that of the feathers by directing water away from the heel, Caribu reported.

Horse Feathers

Some horse breeds' lower legs and feet develop fine hairs called feathers.

They are not the same as the hairy tufts on the back of the hoof, called fetlocks.

Feathers cover the entire lower leg and are primarily found on draft horses with bulky bodies that are heavily muscled.

Curiously, according to Deep Hallow Ranch, ergots can also be discovered concealed inside the fetlock of a horse that lacks feathers but has fetlocks.

Because they are concealed by the fetlocks or feathers, ergots frequently become thicker and knobbier than horse chestnuts.