Ergots are small growths found on the lower legs of horses. Their origin and purpose often prompt questions from owners. Understanding what ergots are and why horses possess them provides insight into equine anatomy and evolutionary history.
What Exactly Are Ergots?
Ergots are small, hardened skin growths located on a horse’s fetlock joint. They are typically found on all four legs. Their visibility varies, often concealed by hair. Ergots appear as rough, pea-sized to bean-sized growths.
These structures are composed of keratinized tissue, similar to hooves or chestnuts. Ergots are living tissue that continues to grow. Their presence is a normal part of equine anatomy and they are not typically associated with health concerns.
The Evolutionary Story of Ergots
Ergots are vestigial remnants, meaning they are non-functional structures left over from a horse’s evolutionary past. They are believed to be the reduced remains of the digital pads or sole pads from multi-toed ancestors of modern horses. Early equids, such as Eohippus, which lived approximately 55 million years ago, were small, forest-dwelling creatures with multiple toes, typically three or four, each supported by a pad.
As horses evolved and their habitats shifted from soft, forested terrain to hard, open grasslands, their anatomy adapted for speed and efficiency. This evolutionary pressure led to the reduction of multiple toes into the single, strong hoof seen in modern horses. During this process, the once-functional digital pads became increasingly smaller and lost their original purpose, persisting only as the small, non-functional ergots. The ergot is considered akin to the sole pad found in other odd-toed ungulates like tapirs.
Ergots in Modern Horses
In contemporary horses, ergots serve no significant functional purpose. While some research explores minor potential roles, such as being a meeting point for connective tissues or aiding in water drainage, these are not primary functions. They are anatomical curiosities reflecting a long evolutionary journey.
Unlike chestnuts, which can grow large and flaky, ergots typically remain small and are often worn down naturally by contact with the ground. Consequently, they rarely require active trimming or maintenance. However, if an ergot does become excessively large or causes a horse discomfort, a farrier or veterinarian can safely trim it. This process is usually simple and painless when performed correctly, often after softening the growth.