Chestnut (horse anatomy)
{{Short description|Equine body part}}
{{Confused|Horse chestnut}}
{{for|the coat color in horses|Chestnut (coat)}}
File:Chestnut on the leg of a horse.jpg
The chestnut, also known as a night eye, is a callosity on the body of a horse or other equine, found on the inner side of the leg above the knee on the foreleg and, if present, below the hock on the hind leg. It is believed to be a vestigial toe, and along with the ergot form the three toes of some other extinct Equidae.{{cite book|title=The origin and influence of the Thoroughbred horse|author=William Ridgeway|publisher=University Press|year=1905|pages=[https://archive.org/details/originandinflue00ridggoog/page/n560 538]|url=https://archive.org/details/originandinflue00ridggoog|quote=ergot.}} chapter 2{{cite book|title=Horse|last=Walker|first=Elaine|year=2008|publisher=Reaktion Books}} Darren Naish dissents from this belief, noting that the chestnut is "not associated with the metacarpus or metatarsus, the only places where digits occur."{{cite web|last1=Naish|first1=Darren|title=Fantastic Asses|url=http://blogs.scientificamerican.com/tetrapod-zoology/2013/09/05/fantastic-asses/|website=Tet Zoo|publisher=Scientific American|accessdate=26 April 2015|date=2013-09-05}}
Chestnuts vary in size and shape and are sometimes compared to the fingerprints in humans. For purposes of identification, some breed registries require photographs of them, among other individual characteristics.{{cite book
|title=The Horse
|author1=J. Warren Evans |author2=Anthony Borton |author3=Harold Hintz |author4=L. Dale van Vleck |publisher=Macmillan
|edition=2nd
|year=1990
|page=80
|isbn=978-0-7167-1811-6
|url=https://books.google.com/books?id=oyHr4hVs0m0C&q=fingerprints&pg=PA80
}} However, because chestnuts grow over time and horse groomers often peel or trim off the outer layers for neatness, their appearance is subject to change.
Distribution among equines
File:Somali Wild Ass chestnuts.jpg foal with black chestnut on foreleg, no chestnut on hindleg]]
The evolution of the horse involved a reduction in the number of toes to one, along with other changes to the ancestral equid foot, and the chestnut is thought to correspond to the wrist pad of dogs and cats. Alternatively, it may be a vestigial scent gland similar to those found in some deer and other animals.{{cite book
|title=The origin and influence of the Thoroughbred horse
|author=William Ridgeway
|publisher=University Press
|year=1905
|pages=[https://archive.org/details/originandinflue00ridggoog/page/n560 538]
|url=https://archive.org/details/originandinflue00ridggoog
|quote=chestnut.
}} chapter 2
The domestic horse is almost alone among extant equines in having chestnuts on the hind legs. Chestnuts are absent from the hind legs of asses and zebras.{{cite journal
|journal=Nature
|year=1906
|volume=74
|issue=1909
|pages=113–115
|title=The tarpan and its relationship with wild and domestic horses
|author=J. C. Ewart
|url=https://books.google.com/books?id=G9URAAAAYAAJ&pg=PA113
|doi=10.1038/074113a0
|authorlink=James Cossar Ewart
|doi-access=free
|url-access=subscription
}} The majority of domestic horses have chestnuts on all four legs, as does the Przewalski's horse, but a few horse breeds are reported to lack chestnuts on the hind legs. These include:
- Banker horse (most individuals){{cite web |url=http://www.corollawildhorses.com/Images/HOA%20Report/hoa-report.pdf |title=Corolla and Shackleford Horse of the Americas Inspection |accessdate=2009-01-11 |last1=Ives |first1=Vickie |first2=Tom |last2=Norush |first3=Gretchen |last3=Patterson |date=February 2007 |publisher=Horse of the Americas |url-status=dead |archiveurl=https://web.archive.org/web/20090318105441/http://www.corollawildhorses.com/Images/HOA%20Report/hoa-report.pdf |archivedate=2009-03-18 }}
- Caspian pony (some individuals)
- Icelandic horse (most individuals){{cite book|last1=Björnsson, Sveinsson|title=The Icelandic horse|year=2006|publisher=Edda Publishing|isbn=9979-3-2709-X|page=206}}
Grooming
{{Unreferenced section|date=August 2023}}
Chestnuts grow over time, protruding from the surface of the leg. Grooming for horse showing may include peeling or trimming the outer layers to give a neater appearance to the leg; they may peel more easily if softened first with baby oil or moisturizer. Also, if the horse is exercised so that it has sweated, the chestnut is temporarily softened by the body moisture and can be peeled easily. If left alone, eventually the chestnut peels naturally. Avoid over-trimming. While chestnuts don’t bleed, cutting too deep can cause pain, inflammation, or infection. It’s best to consult a veterinarian or farrier if you’re unsure.{{cite web |last1=VIKKI |first1=VIKKI |title=Discover the Purpose of Horse Chestnuts |url=https://horsemperor.com/what-is-a-chestnut-on-a-horse/ |website=Horse Emperor |publisher=VIKKI |access-date=June 20, 2025}}
See also
References
{{reflist}}
External links
- [http://www.cowboyway.com/What/WhatAreChestnuts.htm Chestnuts And Ergots In Horses]
- {{Commons-inline|Category:Chestnut (Horse Anatomy)}}