View source for Horse

{{Short description|Domesticated equine}}
{{Other uses}}
{{pp|small=yes}}
{{Good article}}
{{Subspeciesbox
| name = Horse
| status = DOM
| image = Nokota Horses cropped.jpg
| image_caption = <!-- Caption intentionally left blank per consensus to avoid promoting one breed. -->
| image_alt = Two Nokota horses standing in open grassland with rolling hills and trees visible in the background.
| genus = Equus
| species = ferus
| species_link = Wild horse
| subspecies = caballus
| authority = [[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]]<ref name="Linn1758">{{cite book | last = Linnaeus | first = Carolus | author-link = Carl Linnaeus | title = Systema naturae per regna tria naturae :secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis | publisher = Holmiae (Laurentii Salvii) | year = 1758 | page = 73 | url = https://www.biodiversitylibrary.org/page/726976 | access-date = 2008-09-08 | volume = 1 | edition = 10th | archive-date = 2018-10-12 | archive-url = https://web.archive.org/web/20181012203414/https://www.biodiversitylibrary.org/page/726976 | url-status = live }}</ref>
| synonyms = at least 48 published
| synonyms_ref = <ref name=MSW3/>
}}
The '''horse''' ('''''Equus ferus caballus''''')<ref name=MSW3>{{MSW3 Perissodactyla | id = 14100016 | pages = 630–631}}</ref><ref>{{cite journal|last=International Commission on Zoological Nomenclature|year=2003|title=Usage of 17 specific names based on wild species which are pre-dated by or contemporary with those based on domestic animals (Lepidoptera, Osteichthyes, Mammalia): conserved. Opinion 2027 (Case 3010)|journal=Bull. Zool. Nomencl.|volume=60|issue=1|pages=81–84|url=http://www.nhm.ac.uk/hosted_sites/iczn/BZNMar2003opinions.htm|archive-url=https://web.archive.org/web/20070821235959/http://www.nhm.ac.uk/hosted_sites/iczn/BZNMar2003opinions.htm|archive-date=2007-08-21}}</ref> is a [[Domestication|domesticated]], [[odd-toed ungulate|one-toed]], [[ungulate|hoofed mammal]]. It belongs to the taxonomic family [[Equidae]] and is one of two [[Extant taxon|extant]] [[subspecies]] of [[wild horse|''Equus ferus'']]. The horse has [[evolution of the horse|evolved]] over the past 45 to 55&nbsp;million years from a small multi-toed creature, close to ''[[Eohippus]]'', into the large, single-toed animal of today. Humans began domesticating horses around 4000 [[Common Era|BCE]], and their [[domestication of the horse|domestication]] is believed to have been widespread by 3000 BCE. Horses in the subspecies ''caballus'' are domesticated, although some domesticated populations live in the wild as [[feral horse]]s. These feral populations are not true [[wild horse]]s, which are horses that never have been domesticated and historically linked to the megafauna category of species. There is an extensive, specialized vocabulary used to describe equine-related concepts, covering everything from [[equine anatomy|anatomy]] to life stages, size, [[equine coat color|colors]], [[horse markings|markings]], [[horse breed|breeds]], [[horse gait|locomotion]], and behavior.

Horses are [[Cursorial|adapted to run]], allowing them to quickly escape predators, and possess a good [[sense of balance]] and a strong [[fight-or-flight response]]. Related to this need to flee from predators in the wild is an unusual trait: horses are able to sleep both standing up and lying down, with younger horses tending to sleep significantly more than adults.<ref>{{cite web|url=https://www.thespruce.com/learn-how-all-horses-sleep-1887328|title=Do You Know How Horses Sleep?|access-date=12 September 2018|archive-date=22 January 2018|archive-url=https://web.archive.org/web/20180122181803/https://www.thespruce.com/learn-how-all-horses-sleep-1887328|url-status=live}}</ref> Female horses, called [[mare]]s, carry their young for approximately 11&nbsp;months and a young horse, called a [[foal]], can stand and run shortly following birth. Most domesticated horses begin training under a [[saddle]] or in a [[Horse harness|harness]] between the ages of two and four. They reach full adult development by age five, and have an average lifespan of between 25 and 30&nbsp;years.

Horse breeds are loosely divided into three categories based on general temperament: spirited "hot bloods" with speed and endurance; "cold bloods", such as [[draft horse]]s and some [[Pony|ponies]], suitable for slow, heavy work; and "[[warmblood]]s", developed from crosses between hot bloods and cold bloods, often focusing on creating breeds for specific riding purposes, particularly in Europe. There are more than 300&nbsp;breeds of horse in the world today, developed for many different uses.

Horses and humans interact in a wide variety of sport competitions and non-competitive recreational pursuits as well as in working activities such as [[Mounted police|police work]], [[working animal|agriculture]], entertainment, and [[Equine-assisted therapy|therapy]]. Horses were historically used in warfare, from which a wide variety of [[equestrianism|riding]] and [[driving (horse)|driving]] techniques developed, using many different styles of [[Horse tack|equipment]] and methods of control. Many products are derived from horses, including [[horse meat|meat]], [[horse milk|milk]], [[horsehide|hide]], [[horsehair|hair]], bone, and [[Premarin|pharmaceuticals extracted from the urine of pregnant mares]]. Humans provide domesticated horses with food, water, and shelter, as well as attention from specialists such as [[veterinarian]]s and [[farrier]]s.

==Biology==
{{Main|Equine anatomy}}
[[File:Points of a horse.jpg|thumb|External anatomy of a horse<ref>{{cite book|last=Goody|first=John|title=Horse Anatomy|edition=2nd|publisher=J A Allen|isbn=0-85131-769-3|year=2000}}</ref><ref>{{cite book|last1=Pavord|first1=Tony|last2=Pavord|first2=Marcy|title=Complete Equine Veterinary Manual|publisher=David & Charles|isbn=978-0-7153-1883-6|year=2007}}</ref>|upright=1.5|alt=Diagram of a horse with some parts labeled.]]

===Lifespan and life stages===
Depending on breed, [[horse care|management]] and environment, the modern domestic horse has a life expectancy of 25 to 30&nbsp;years.<ref name=Ensminger46/> Uncommonly, a few animals live into their 40s and, occasionally, beyond.<ref>{{cite web|url=http://www.omafra.gov.on.ca/english/livestock/horses/facts/info_age.htm|title=The Age of a Horse|publisher=Government of Ontario|website=Ministry of Agriculture, Food and Rural Affairs|author=Wright, B.|date=March 29, 1999|access-date=2009-10-21|url-status=dead|archive-url=https://web.archive.org/web/20100120031232/http://www.omafra.gov.on.ca/english/livestock/horses/facts/info_age.htm|archive-date=January 20, 2010}}</ref> The oldest verifiable record was "[[Old Billy]]", a 19th-century horse that lived to the age of 62.<ref name=Ensminger46/> In modern times, Sugar Puff, who had been listed in ''[[Guinness World Records]]'' as the world's oldest living pony, died in 2007 at age 56.<ref>{{cite web|url= http://www.thehorse.com/viewarticle.aspx?ID=9708|title= World's Oldest Living Pony Dies at 56|access-date= 2007-05-31|author= Ryder, Erin|website= The Horse|archive-date= 2014-01-24|archive-url= https://web.archive.org/web/20140124211019/http://www.thehorse.com/articles/18956/worlds-oldest-living-pony-dies-at-56|url-status= live}}</ref>

Regardless of a horse or pony's actual birth date, for most competition purposes a year is added to its age each January&nbsp;1 of each year in the Northern Hemisphere<ref name=Ensminger46/><ref>{{cite book |title= The Manual of Horsemanship of the British Horse Society and the Pony Club |url= https://archive.org/details/manualofhorseman00pony |url-access= registration |author=British Horse Society |year=1966|edition=6th edition, reprinted 1970 |publisher= British Horse Society |location= Kenilworth, UK |isbn= 0-9548863-1-3|page= [https://archive.org/details/manualofhorseman00pony/page/255 255]}}</ref> and each August&nbsp;1 in the Southern Hemisphere.<ref>{{cite web |url= http://www.studbook.org.au/DisplayPDF.aspx?ty=RULES |format= PDF |title= Rules of the Australian Stud Book |access-date= 2008-07-09 |year= 2007 |publisher= Australian Jockey Club |page= 7 |archive-date= 2013-04-24 |archive-url= https://web.archive.org/web/20130424221902/http://www.studbook.org.au/DisplayPDF.aspx?ty=RULES |url-status= live }}</ref> The exception is in [[endurance riding]], where the minimum age to compete is based on the animal's actual calendar age.<ref name=Endurance>{{cite web|url= http://www.aerc.org/HorseAge.aspx|title= Equine Age Requirements for AERC Rides|access-date= 2011-07-25|publisher= American Endurance Riding Conference|url-status=dead|archive-url= https://web.archive.org/web/20110811110201/http://aerc.org/HorseAge.aspx|archive-date= 2011-08-11}}</ref>

The following terminology is used to describe horses of various ages:
; [[Foal]]
: A horse of either sex less than one year old. A nursing foal is sometimes called a ''suckling'', and a foal that has been weaned is called a ''weanling''.<ref name=Ensminger418>[[#Ensminger|Ensminger]], p. 418</ref> Most domesticated foals are weaned at five to seven months of age, although foals can be weaned at four months with no adverse physical effects.<ref>[[#Giffin|Giffin]], p. 431</ref>
; [[Yearling (horse)|Yearling]]
: A horse of either sex that is between one and two years old.<ref>[[#Ensminger|Ensminger]], p. 430</ref>
; [[Colt (horse)|Colt]]
: A male horse under the age of four.<ref>[[#Ensminger|Ensminger]], p. 415</ref> A common terminology error is to call any young horse a "colt", when the term actually only refers to young male horses.<ref>{{cite book|author1=Becker, Marty|author2=Pavia, Audrey|author3=Spadafori, Gina|author4=Becker, Teresa|title=Why Do Horses Sleep Standing Up?: 101 of the Most Perplexing Questions Answered About Equine Enigmas, Medical Mysteries, and Befuddling Behaviors|publisher=HCI|year=2007|isbn=978-0-7573-0608-2|url=https://archive.org/details/whydohorsessleep0000unse/page/23|page=[https://archive.org/details/whydohorsessleep0000unse/page/23 23]}}</ref>
; [[Filly]]
: A female horse under the age of four.<ref name=Ensminger418/>
; [[Mare]]
: A female horse four years old and older.<ref>[[#Ensminger|Ensminger]], p. 422</ref>
; [[Stallion]]
: A non-castrated male horse four years old and older.<ref>[[#Ensminger|Ensminger]], p. 427</ref> The term "horse" is sometimes used colloquially to refer specifically to a stallion.<ref name=Ensminger420>[[#Ensminger|Ensminger]], p. 420</ref>
; [[Gelding]]
: A [[Neutering|castrated]] male horse of any age.<ref name=Ensminger418/>

In [[horse racing]], these definitions may differ: For example, in the British Isles, [[Thoroughbred]] horse racing defines colts and fillies as less than five years old.<ref>{{cite web|url= http://www.equibase.com/newfan/glossary-full.cfm|title= Glossary of Horse Racing Terms|access-date= 2008-04-03|website= Equibase.com|publisher= Equibase Company, LLC|archive-date= 2008-05-12|archive-url= https://web.archive.org/web/20080512170317/http://www.equibase.com/newfan/glossary-full.cfm|url-status= live}}</ref> However, Australian Thoroughbred racing defines colts and fillies as less than four years old.<ref>{{cite web|url=http://www.studbook.org.au/DisplayPDF.aspx?ty=RULES|title=Rules of the Australian Stud Book|access-date=2010-02-05|page=9|date=July 2008|publisher=Australian Jockey Club Ltd and Victoria Racing Club Ltd|archive-date=2013-04-24|archive-url=https://web.archive.org/web/20130424221902/http://www.studbook.org.au/DisplayPDF.aspx?ty=RULES|url-status=live}}</ref>

===Size and measurement===
The height of horses is measured at the highest point of the [[withers]], where the neck meets the [[back (horse)|back]].<ref name=Whitaker77>[[#Whitaker|Whitaker]], p. 77</ref> This point is used because it is a stable point of the anatomy, unlike the head or neck, which move up and down in relation to the body of the horse.

[[File:Horse-and-pony.jpg|thumb|left|upright=1.4|Size varies greatly among horse breeds, as with this full-sized horse and small pony.|alt=A large brown horse is chasing a small horse in a pasture.]]
In English-speaking countries, the height of horses is often stated in units of [[Hand (unit)|hands]] and inches: one hand is equal to {{convert|101.6|mm|in|0|order=flip}}. The height is expressed as the number of full hands, followed by a [[radix point|point]], then the number of additional inches, and ending with the abbreviation "h" or "hh" (for "hands high"). Thus, a horse described as "15.2 h" is 15 hands plus 2&nbsp;inches, for a total of {{convert|62|in|cm|1}} in height.<ref name=Ensminger51>[[#Ensminger|Ensminger]], p. 51</ref>

The size of horses varies by breed, but also is influenced by [[equine nutrition|nutrition]]. Light-riding horses usually range in height from {{hands|14|to|16|lk=off}} and can weigh from {{convert|380|to|550|kg}}.<ref>[[#Bongianni|Bongianni]], entries 1, 68, 69</ref> Larger-riding horses usually start at about {{hands|15.2|lk=off}} and often are as tall as {{hands|17|lk=off}}, weighing from {{convert|500|to|600|kg|sigfig=3}}.<ref>[[#Bongianni|Bongianni]], entries 12, 30, 31, 32, 75</ref> Heavy or [[draft horse]]s are usually at least {{hands|16|lk=off}} high and can be as tall as {{hands|18|lk=off}} high. They can weigh from about {{convert|700|to|1000|kg|sigfig=3}}.<ref>[[#Bongianni|Bongianni]], entries 86, 96, 97</ref>

The largest horse in recorded history was probably a [[Shire horse]] named [[Sampson (horse)|Mammoth]], who was born in 1848. He stood {{hands|21.2+1/4|lk=off}} high and his peak weight was estimated at {{convert|1524|kg}}.<ref name=Whitaker60>[[#Whitaker|Whitaker]], p. 60</ref> The record holder for the smallest horse ever is [[Thumbelina (horse)|Thumbelina]], a fully mature [[miniature horse]] affected by [[dwarfism]]. She was {{convert|17|in|cm hand|lk=off|order=flip}} tall and weighed {{convert|57|lb|kg|abbr=on|order=flip}}.<ref>{{cite news | title = World's smallest horse has tall order | url = https://www.washingtonpost.com/wp-dyn/content/article/2007/03/19/AR2007031901754.html | date = 2007-03-19 | newspaper = [[The Washington Post]] | agency = [[Associated Press]] | author = Douglas, Jeff | access-date = 2017-03-14 | archive-date = 2017-03-15 | archive-url = https://web.archive.org/web/20170315174315/http://www.washingtonpost.com/wp-dyn/content/article/2007/03/19/AR2007031901754.html | url-status = live }}</ref><ref>{{Cite web|date=2019-09-05|title=Meet the smallest horse in the world that's shorter than a greyhound|url=https://www.guinnessworldrecords.com/news/2019/9/meet-the-smallest-horse-in-the-world-thats-shorter-than-a-greyhound-588674|access-date=2021-07-06|website=Guinness World Records|language=en-GB|archive-date=2021-08-04|archive-url=https://web.archive.org/web/20210804002359/https://www.guinnessworldrecords.com/news/2019/9/meet-the-smallest-horse-in-the-world-thats-shorter-than-a-greyhound-588674|url-status=live}}</ref>

====Ponies====
{{Main|Pony}}
[[Pony|Ponies]] are [[Taxonomy (biology)|taxonomically]] the same animals as horses. The distinction between a horse and pony is commonly drawn on the basis of height, especially for competition purposes. However, height alone is not dispositive; the difference between horses and ponies may also include aspects of [[phenotype]], including conformation and temperament.

The traditional standard for height of a horse or a pony at maturity is {{hands|14.2|lk=off}}. An animal {{hands|14.2|lk=off}} or over is usually considered to be a horse and one less than {{hands|14.2|lk=off}} a pony,{{r|EnsmingerHT|page=12}} but there are many exceptions to the traditional standard. In Australia, ponies are considered to be those under {{hands|14|lk=off}}.<ref>{{cite book|author1=Howlett, Lorna |author2=Philip Mathews |title=Ponies in Australia |publisher=Philip Mathews Publishers |location=Milson's Point, NSW |isbn=0-908001-13-4 |year=1979 |page=14}}</ref> For competition in the [[western riding|Western]] division of the [[United States Equestrian Federation]], the cutoff is {{hands|14.1|lk=off}}.<ref>{{cite web |url=http://www.usef.org/_IFrames/RuleBook/rulebooks.aspx |title=2012 United States Equestrian Federation, Inc. Rule Book |publisher=United States Equestrian Federation |page=Rule WS 101 |url-status=dead |archive-url=https://web.archive.org/web/20120415003731/http://www.usef.org/_IFrames/RuleBook/rulebooks.aspx |archive-date=2012-04-15 }}</ref> The [[International Federation for Equestrian Sports]], the world governing body for horse sport, uses [[metric system|metric]] measurements and defines a pony as being any horse measuring less than {{convert|148|cm|in|2}} at the withers without shoes, which is just over {{hands|14.2|lk=off}}, and {{convert|149|cm|in hands|2|lk=off}}, with shoes.<ref>{{cite web | url=http://www.fei.org/sites/default/files/Annex%20XVII%20-%20Extracts%20Ponies.pdf | title=Annex XVII: Extracts from Rules for Pony Riders and Children, 9th edition | publisher=Fédération Equestre Internationale | year=2009 | access-date=2010-03-07 | url-status=dead | archive-url=https://web.archive.org/web/20120911122158/http://www.fei.org/sites/default/files/Annex%20XVII%20-%20Extracts%20Ponies.pdf | archive-date=2012-09-11 }}</ref>

Height is not the sole criterion for distinguishing horses from ponies. [[Breed registry|Breed registries]] for horses that typically produce individuals both under and over {{hands|14.2|lk=off}} consider all animals of that breed to be horses regardless of their height.<ref>For example, the [[Missouri Fox Trotter]], or the [[Arabian horse]]. See [[#McBane|McBane]], pp. 192, 218</ref> Conversely, some pony breeds may have features in common with horses, and individual animals may occasionally mature at over {{hands|14.2|lk=off}}, but are still considered to be ponies.<ref>For example, the [[Welsh Pony]]. See [[#McBane|McBane]], pp. 52–63</ref>

Ponies often exhibit thicker manes, tails, and overall coat. They also have proportionally shorter legs, wider barrels, heavier bone, shorter and thicker necks, and short heads with broad foreheads. They may have calmer temperaments than horses and also a high level of intelligence that may or may not be used to cooperate with human handlers.{{r|EnsmingerHT|pages=11-12}}{{Failed verification|date=April 2024|reason=Is not found on pages 11-12, and doesn't appear to be in this book.}} Small size, by itself, is not an exclusive determinant. For example, the [[Shetland pony]] which averages {{hands|10|lk=off}}, is considered a pony.{{r|EnsmingerHT|page=12}}Conversely, breeds such as the [[Falabella]] and other [[miniature horse]]s, which can be no taller than {{convert|30|in|cm hand|lk=off|order=flip}}, are classified by their [[breed registry|registries]] as very small horses, not ponies.<ref>[[#McBane|McBane]], p. 200</ref>

===Genetics===
Horses have 64 [[chromosome]]s.<ref>{{cite web |url=http://www.vivo.colostate.edu/hbooks/genetics/medgen/chromo/species.html |title=Chromosome Numbers in Different Species |publisher=Vivo.colostate.edu |date=1998-01-30 |access-date=2013-04-17 |url-status=dead |archive-url=https://web.archive.org/web/20130511210119/http://www.vivo.colostate.edu/hbooks/genetics/medgen/chromo/species.html |archive-date=2013-05-11 }}</ref> The [[horse genome]] was [[DNA sequencing|sequenced]] in 2007. It contains 2.7 billion DNA [[base pair]]s,<ref name=Cornell>{{cite web |url=http://www.vet.cornell.edu/news/articles/09antczakscience.cfm |title=Sequenced horse genome expands understanding of equine, human diseases |publisher=Cornell University College of Veterinary Medicine |date=2012-08-21 |access-date=2013-04-01 |archive-date=2017-10-10 |archive-url=https://web.archive.org/web/20171010200000/http://www.vet.cornell.edu/news/articles/09antczakscience.cfm |url-status=live }}</ref> which is larger than the [[dog genome]], but smaller than the [[human genome]] or the [[bovine genome]].<ref name=ScienceDaily>{{Cite journal |url=https://www.sciencedaily.com/releases/2009/11/091105143708.htm |title=Domestic Horse Genome Sequenced |journal=Science |volume=326 |issue=5954 |pages=865–867 |doi=10.1126/science.1178158 |pmid=19892987 |pmc=3785132 |date=2009-11-05 |access-date=2013-04-01 |last1=Wade |first1=C. M |last2=Giulotto |first2=E |last3=Sigurdsson |first3=S |last4=Zoli |first4=M |last5=Gnerre |first5=S |last6=Imsland |first6=F |last7=Lear |first7=T. L |last8=Adelson |first8=D. L |last9=Bailey |first9=E |last10=Bellone |first10=R. R |last11=Blocker |first11=H |last12=Distl |first12=O |last13=Edgar |first13=R. C |last14=Garber |first14=M |last15=Leeb |first15=T |last16=Mauceli |first16=E |last17=MacLeod |first17=J. N |last18=Penedo |first18=M. C. T |last19=Raison |first19=J. M |last20=Sharpe |first20=T |last21=Vogel |first21=J |last22=Andersson |first22=L |last23=Antczak |first23=D. F |last24=Biagi |first24=T |last25=Binns |first25=M. M |last26=Chowdhary |first26=B. P |last27=Coleman |first27=S. J |last28=Della Valle |first28=G |last29=Fryc |first29=S |last30=Guerin |first30=G |display-authors=29 |bibcode=2009Sci...326..865W |archive-date=2018-11-18 |archive-url=https://web.archive.org/web/20181118204110/https://www.sciencedaily.com/releases/2009/11/091105143708.htm |url-status=live  |issn = 0036-8075}}</ref> The map is available to researchers.<ref>{{cite web |url=http://uswest.ensembl.org/Equus_caballus/Info/Index |title=Ensembl genome browser 71: Equus caballus – Description |publisher=Uswest.ensembl.org |access-date=2013-04-17 |archive-date=2017-10-10 |archive-url=https://web.archive.org/web/20171010200000/http://uswest.ensembl.org/Equus_caballus/Info/Index |url-status=dead }}</ref>

===Colors and markings===
[[File:Horsescd1l-095.jpg|thumb|upright=1.4|[[Bay (horse)|Bay]] (left) and [[chestnut (horse color)|chestnut]] (sometimes called "sorrel") are two of the most common coat colors, seen in almost all breeds.|alt=Two horses in a field. The one on the left is a dark brown with a black mane and tail. The one on the right is a light red all over.]]
{{Main|Equine coat color|Equine coat color genetics|Horse markings}}

Horses exhibit a diverse array of [[Equine coat color|coat colors]] and distinctive [[horse markings|markings]], described by a specialized vocabulary. Often, a horse is classified first by its coat color, before breed or sex.<ref>{{cite book|author=Vogel, Colin B.V.M. |title=The Complete Horse Care Manual |publisher=Dorling Kindersley Publishing, Inc. |location=New York |year=1995 |isbn=0-7894-0170-3 |oclc=32168476 |page=[https://archive.org/details/completehorsecar0000voge/page/14 14] |url=https://archive.org/details/completehorsecar0000voge/page/14}}</ref> Horses of the same color may be distinguished from one another by white [[horse markings|markings]],<ref>{{cite book |title=A Basic Guide to Horse Care and Management|author1=Mills, Bruce |author2=Barbara Carne |year=1988 |publisher=Howell Book House |location=New York |isbn=0-87605-871-3 |oclc=17507227|pages= 72–73}}</ref> which, along with various spotting patterns, are inherited separately from coat color.<ref>{{cite journal |url=http://www.thehorse.com/ViewArticle.aspx?ID=4354 |title=A Horse of a Different Color |journal=The Horse |url-access=registration |access-date=2010-02-11 |author=Corum, Stephanie J. |date=May 1, 2003 |archive-date=2015-09-18 |archive-url=https://web.archive.org/web/20150918013937/http://www.thehorse.com/articles/13855/a-horse-of-a-different-color |url-status=live }}</ref>

Many [[Equine coat color genetics|genes]] that create horse coat colors and patterns have been identified. Current genetic tests can identify at least 13 different [[allele]]s influencing coat color,<ref name=UCVGL/> and research continues to discover new genes linked to specific traits. The basic coat colors of [[chestnut (horse color)|chestnut]] and [[black horse|black]] are determined by the [[gene]] controlled by the [[Melanocortin 1 receptor]],<ref name=Marklund1996>{{cite journal |last=Marklund |first=L. |author2=M. Johansson Moller |author3=K. Sandberg |author4=L. Andersson |title=A missense mutation in the gene for melanocyte-stimulating hormone receptor (MC1R) is associated with the chestnut coat color in horses |journal=Mammalian Genome |volume=7 |pages=895–899 |year=1996 |doi=10.1007/s003359900264 |pmid=8995760 |issue=12 |s2cid=29095360}}</ref> also known as the "extension gene" or "red factor".<ref name=UCVGL/> Its recessive form is "red" (chestnut) and its dominant form is black.<ref name=UCDIntro/> Additional [[gene]]s control suppression of black color to [[point coloration]] that results in a [[bay (horse)|bay]], spotting patterns such as [[pinto horse|pinto]] or [[leopard complex|leopard]], [[dilution gene]]s such as [[palomino]] or [[dun gene|dun]], as well as [[gray horse|greying]], and all the other factors that create the many possible coat colors found in horses.<ref name=UCVGL>{{cite web|url= http://www.vgl.ucdavis.edu/services/coatcolorhorse.php|title= Horse Coat Color Tests|access-date= 2008-05-01|website= Veterinary Genetics Laboratory|publisher= University of California|archive-date= 2008-02-19|archive-url= https://web.archive.org/web/20080219095454/http://www.vgl.ucdavis.edu/services/coatcolorhorse.php|url-status= live}}</ref>

Horses that have a white coat color are often mislabeled; a horse that looks "white" is usually a middle-aged or older [[gray horse|gray]]. Grays are born a darker shade, get lighter as they age, but usually keep black skin underneath their white hair coat (with the exception of pink skin under white [[horse markings|markings]]). The only horses properly called [[white horse|white]] are born with a predominantly white hair coat and pink skin, a fairly rare occurrence.<ref name=UCDIntro>{{cite web|url= http://www.vgl.ucdavis.edu/services/coatcolor.php|title= Introduction to Coat Color Genetics|access-date= 2008-05-01|website= Veterinary Genetics Laboratory|publisher= University of California|archive-date= 2017-10-10|archive-url= https://web.archive.org/web/20171010200000/http://www.vgl.ucdavis.edu/services/coatcolor.php|url-status= live}}</ref> Different and unrelated [[Genetics|genetic]] factors can produce white coat colors in horses, including several different alleles of [[dominant white]] and the [[sabino horse|sabino-1 gene]].<ref name=haase2009-similar>{{cite journal |author=Haase B |title=Allelic Heterogeneity at the Equine KIT Locus in Dominant White (W) Horses |journal=PLOS Genetics |volume=3 |issue=11 |pages=e195 |year=2007 |pmid=17997609 |pmc=2065884 |doi=10.1371/journal.pgen.0030195 |author2=Brooks SA |author3=Schlumbaum A |display-authors=3 |last4=Azor |first4=Pedro J. |last5=Bailey |first5=Ernest |last6=Alaeddine |first6=Ferial |last7=Mevissen |first7=Meike |last8=Burger |first8=Dominik |last9=Poncet |first9=Pierre-André |doi-access=free }}</ref> However, there are no "[[Albinism|albino]]" horses, defined as having both pink skin and red eyes.<ref name=Duplicatetest>{{cite journal |title= Genetic mapping of dominant white (W), a homozygous lethal condition in the horse (''Equus caballus'') |author1= Mau, C. |author2= Poncet, P. A. |author3= Bucher, B. |author4= Stranzinger, G. |author5= Rieder, S. |journal= Journal of Animal Breeding and Genetics|volume= 121|doi= 10.1111/j.1439-0388.2004.00481.x |year= 2004 |pages= 374–383 |issue= 6}}</ref>

===Reproduction and development===
{{Main|Horse breeding}}

[[File:Mare foal poland.jpg|thumb|Mare with a foal]]
[[Gestation]] lasts approximately 340&nbsp;days, with an average range 320–370 days,<ref name=Ensminger156>[[#Ensminger|Ensminger]], p. 156</ref><ref>{{Cite web |title=How Long is a Horse Pregnant? |url=https://talkoftheturf.com/article/how-long-is-a-horse-pregnant |access-date=2023-03-25 |website=Talk of the Turf |language=en}}</ref> and usually results in one [[foal]]; twins are rare.<ref>{{cite web|url= http://www2.okstate.edu/pio/twinfoals.html|access-date= 2008-09-23|title= Rare Twin Foals Born at Vet Hospital: Twin Birth Occurrences Number One in Ten Thousand|author= Johnson, Tom|website= Communications Services, Oklahoma State University|publisher= Oklahoma State University|archive-url= https://web.archive.org/web/20121012052136/http://www2.okstate.edu/pio/twinfoals.html|archive-date= 2012-10-12|url-status= dead}}</ref> Horses are a precocial species, and foals are capable of standing and running within a short time following birth.<ref>{{cite book |author1=Miller, Robert M. |author2=Rick Lamb|title=Revolution in Horsemanship and What it Means to Mankind |publisher= Lyons Press|location=Guilford, CT|year=2005|isbn=1-59228-387-X |oclc=57005594|pages=102–103}}</ref> Foals are usually born in the spring. The [[estrous cycle]] of a mare occurs roughly every 19–22 days and occurs from early spring into autumn. Most mares enter an ''anestrus'' period during the winter and thus do not cycle in this period.<ref name=Ensminger150>[[#Ensminger|Ensminger]], p. 150</ref> Foals are generally [[weaning|weaned]] from their mothers between four and six months of age.<ref>{{cite web|url=http://www.extension.org/pages/29352/reducing-weaning-stress-in-foals|author=Kline, Kevin H.|title=Reducing weaning stress in foals |publisher=Montana State University eXtension|date=2010-10-07|access-date=2012-04-03|url-status=dead|archive-url=https://web.archive.org/web/20120322182958/http://www.extension.org/pages/29352/reducing-weaning-stress-in-foals|archive-date=2012-03-22}}</ref>

Horses, particularly colts, are sometimes physically capable of reproduction at about 18&nbsp;months, but domesticated horses are rarely allowed to breed before the age of three, especially females.{{r|EnsmingerHT|page=129}} Horses four years old are considered mature, although the skeleton normally continues to develop until the age of six; maturation also depends on the horse's size, breed, sex, and quality of care. Larger horses have larger bones; therefore, not only do the bones take longer to form [[Bone|bone tissue]], but the [[epiphyseal plate]]s are larger and take longer to convert from [[cartilage]] to bone. These plates convert after the other parts of the bones, and are crucial to development.<ref>{{cite web|url=http://www.equineortho.colostate.edu/questions/dod.htm|title=Developmental Orthopaedic Disease: Problems of Limbs in young Horses|access-date=2008-04-20|author=McIlwraith, C.W.|publisher=Colorado State University|website=Orthopaedic Research Center|archive-date=2013-01-14|archive-url=https://web.archive.org/web/20130114221212/http://csu-cvmbs.colostate.edu/academics/clinsci/equine-orthopaedic-research-center/Pages/default.aspx|url-status=live}}</ref>

Depending on maturity, breed, and work expected, horses are usually put under saddle and [[horse training|trained]] to be ridden between the ages of two and four.<ref name=Train163>{{cite book|author=Thomas, Heather Smith |title=Storey's Guide to Training Horses: Ground Work, Driving, Riding |publisher=Storey Publishing |location=North Adams, MA |year=2003 |isbn=1-58017-467-1 |page=[https://archive.org/details/storeysguidetotr0000thom/page/163 163] |url=https://archive.org/details/storeysguidetotr0000thom/page/163}}</ref> Although [[Thoroughbred]] [[Horse racing|race horses]] are put on the track as young as the age of two in some countries,<ref>{{cite web|url= http://www.jockeyclub.com/factbook.asp?section=11|title= 2-Year-Old Racing (US and Canada)|access-date= 2008-04-28|website= Online Fact Book|publisher= Jockey Club|archive-date= 2013-02-16|archive-url= https://web.archive.org/web/20130216002618/http://www.jockeyclub.com/factbook.asp?section=11|url-status= live}}</ref> horses specifically bred for sports such as [[dressage]] are generally not put under saddle until they are three or four years old, because their bones and muscles are not solidly developed.<ref>{{cite book |title=The USDF Guide to Dressage |url=https://books.google.com/books?id=9NNobNYAiroC&pg=PA272 |author1=Bryant, Jennifer Olson |author2=George Williams |publisher=Storey Publishing |year=2006 |isbn=978-1-58017-529-6 |pages=271–272 |access-date=2020-09-28 |archive-date=2023-03-20 |archive-url=https://web.archive.org/web/20230320223812/https://books.google.com/books?id=9NNobNYAiroC&pg=PA272 |url-status=live }}</ref> For [[endurance riding]] competition, horses are not deemed mature enough to compete until they are a full 60&nbsp;calendar months (five years) old.<ref name=Endurance/>

===Anatomy===
{{Main|Equine anatomy|Muscular system of the horse|Respiratory system of the horse|Circulatory system of the horse}}

====Skeletal system====
{{Main|Skeletal system of the horse}}
[[File:Horse anatomy.svg|thumb|upright=1.4|The skeletal system of a modern horse|alt=Diagram of a horse skeleton with major parts labeled.]]
The horse skeleton averages 205 bones.<ref name=Evans90>{{cite book|author=Evans, J. |title=The Horse |edition=Second |publisher=Freeman |location=New York |year=1990 |isbn=0-7167-1811-1 |oclc=20132967 |page=[https://archive.org/details/isbn_9780716718116/page/90 90] |url= https://archive.org/details/isbn_9780716718116/page/90}}</ref> A significant difference between the horse skeleton and that of a human is the lack of a [[Clavicle|collarbone]]—the horse's [[Equine forelimb anatomy|forelimbs]] are attached to the [[Vertebral column|spinal column]] by a powerful set of muscles, tendons, and ligaments that attach the [[Scapula|shoulder blade]] to the torso. The horse's four legs and hooves are also unique structures. Their leg bones are proportioned differently from those of a human. For example, the body part that is called a horse's "knee" is actually made up of the [[carpal bones]] that correspond to the human [[wrist]]. Similarly, the [[hock (anatomy)|hock]] contains bones equivalent to those in the human [[ankle]] and [[heel]]. The lower leg bones of a horse correspond to the bones of the human hand or foot, and the [[Equine anatomy|fetlock]] (incorrectly called the "ankle") is actually the proximal [[sesamoid bone]]s between the [[Equine anatomy|cannon]] bones (a single equivalent to the human [[Metacarpus|metacarpal]] or [[metatarsal bones]]) and the [[proximal phalanges]], located where one finds the "knuckles" of a human. A horse also has no muscles in its legs below the knees and hocks, only skin, hair, bone, [[tendon]]s, [[ligament]]s, [[cartilage]], and the assorted specialized tissues that make up the [[horse hoof|hoof]].<ref name=Ensminger21>[[#Ensminger|Ensminger]], pp. 21–25</ref>

====Hooves====
{{Main|Horse hoof|Horseshoe|Farrier}}

The critical importance of the feet and legs is summed up by the traditional adage, "no foot, no horse".<ref name=Ensminger367>[[#Ensminger|Ensminger]], p. 367</ref> The [[horse hoof]] begins with the [[distal phalanges]], the equivalent of the human fingertip or tip of the toe, surrounded by [[cartilage]] and other specialized, blood-rich soft tissues such as the [[Horse hoof#Internal structures|laminae]]. The exterior hoof wall and horn of the sole is made of [[keratin]], the same material as a human [[Nail (anatomy)|fingernail]].<ref>[[#Giffin|Giffin]], p. 304</ref> The result is that a horse, weighing on average {{convert|500|kg}},<ref>[[#Giffin|Giffin]], p. 457</ref> travels on the same bones as would a human on tiptoe.<ref>{{cite web |url= http://www.cvm.uiuc.edu/petcolumns/showarticle_pf.cfm?id=118|title= Yes, The Shin Bone Is Connected to the Ankle Bone |access-date=2008-04-05 |author= Fuess, Theresa A.|website= Pet Column |publisher= University of Illinois |archive-url = https://web.archive.org/web/20060909161307/http://www.cvm.uiuc.edu/petcolumns/showarticle_pf.cfm?id=118 |archive-date = September 9, 2006}}</ref> For the protection of the hoof under certain conditions, some horses have [[horseshoe]]s placed on their feet by a professional [[farrier]]. The hoof continually grows, and in most domesticated horses needs to be trimmed (and [[horseshoe]]s reset, if used) every five to eight weeks,<ref>[[#Giffin|Giffin]], pp. 310–312</ref> though the hooves of horses in the wild wear down and regrow at a rate suitable for their terrain.

====Teeth====
{{Main|Horse teeth}}

Horses are adapted to [[grazing]]. In an adult horse, there are 12&nbsp;[[incisor]]s at the front of the mouth, adapted to biting off the grass or other vegetation. There are 24&nbsp;teeth adapted for chewing, the [[premolar]]s and [[Molar (tooth)|molars]], at the back of the mouth. Stallions and geldings have four additional teeth just behind the incisors, a type of [[Canine tooth|canine teeth]] called "tushes". Some horses, both male and female, will also develop one to four very small [[Vestigiality|vestigial]] teeth in front of the molars, known as "wolf" teeth, which are generally removed because they can interfere with the [[bit (horse)|bit]]. There is an empty interdental space between the incisors and the molars where the bit rests directly on the gums, or "bars" of the horse's mouth when the horse is [[bridle]]d.<ref>{{cite book |last=Kreling |first=Kai |title=Horses' Teeth and Their Problems: Prevention, Recognition, and Treatment |chapter-url=https://books.google.com/books?id=3q1LINmOkOIC&pg=PA117-IA1 |year=2005 |publisher=Globe Pequot |location=Guilford, CT |isbn=1-59228-696-8 |chapter=The Horse's Teeth |oclc=59163221 |pages=12–13 }}{{Dead link|date=April 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

An estimate of a horse's age can be made from looking at its teeth. The teeth continue to erupt throughout life and are worn down by grazing. Therefore, the incisors show changes as the horse ages; they develop a distinct wear pattern, changes in tooth shape, and changes in the angle at which the chewing surfaces meet. This allows a very rough estimate of a horse's age, although diet and veterinary care can also affect the rate of tooth wear.<ref name=Ensminger46>[[#Ensminger|Ensminger]], pp. 46–50</ref>

====Digestion====
{{Main|Equine anatomy#Digestive system|Equine nutrition|l1=Equine digestive system}}
Horses are [[herbivore]]s with a digestive system adapted to a [[forage]] diet of grasses and other plant material, consumed steadily throughout the day. Therefore, compared to humans, they have a relatively small stomach but very long intestines to facilitate a steady flow of nutrients. A {{convert|450|kg|adj=on}} horse will eat {{convert|7|to|11|kg}} of food per day and, under normal use, drink {{convert|38|to|45|L}} of [[water]]. Horses are not [[ruminant]]s, having only one stomach, like humans. But unlike humans, they can digest [[cellulose]], a major component of grass, through the process of  [[hindgut fermentation]]. Cellulose fermentation by symbiotic bacteria and other microbes occurs in the [[cecum]] and the [[large intestine]]. Horses cannot [[Vomiting|vomit]], so digestion problems can quickly cause [[horse colic|colic]], a leading cause of death.<ref>[[#Giffin|Giffin]], p. 175</ref> Although horses do not have a [[gallbladder]], they tolerate high amounts of fat in their diet.<ref>{{Cite journal |date=2001 |title=Role of dietary carbohydrate and fat in horses with equine polysaccharide storage myopathy |journal=Journal of the American Veterinary Medical Association |doi=10.2460/javma.2001.219.1537 |last1=Valentine |first1=Beth A. |last2=Van Saun |first2=Robert J. |last3=Thompson |first3=Kent N. |last4=Hintz |first4=Harold F. |volume=219 |issue=11 |pages=1537–1544 |pmid=11759989 |doi-access=free }}</ref><ref>{{Cite journal |date=2010 |title=The gall bladder and bile ducts |url=https://www.sciencedirect.com/science/article/abs/pii/S0263931910000542 |journal=Surgery (Oxford) |doi=10.1016/j.mpsur.2010.02.007 |last1=Ellis |first1=Harold |volume=28 |issue=5 |pages=218–221 |access-date=2021-05-11 |archive-date=2021-05-12 |archive-url=https://web.archive.org/web/20210512150222/https://www.sciencedirect.com/science/article/abs/pii/S0263931910000542 |url-status=live }}</ref>

====Senses====
[[File:Pferdeauge.jpg|thumb|A horse's eye|alt=Close up of a horse eye, which is dark brown with lashes on the top eyelid]]
{{See also|Equine vision}}
The horses' senses are based on their status as [[predation|prey animals]], where they must be aware of their surroundings at all times.<ref name=Ensminger309>[[#Ensminger|Ensminger]], pp. 309–310</ref> They are lateral-eyed, meaning that their eyes are positioned on the sides of their heads.<ref>{{cite journal |url = http://www.thehorse.com/ViewArticle.aspx?ID=15938 |title = Eye Position and Animal Agility Study Published |journal = The Horse |date = March 7, 2010 |access-date = 2010-03-11 |archive-date = 2015-07-23 |archive-url = https://web.archive.org/web/20150723214909/http://www.thehorse.com/articles/25141/eye-position-and-animal-agility-study-published |url-status = live }} Press Release, citing February 2010 Journal of Anatomy, Dr. Nathan Jeffery, co-author, University of Liverpool.</ref> This means that horses have a range of vision of more than 350°, with approximately 65° of this being [[binocular vision]] and the remaining 285° [[monocular vision]].<ref name="Sellnow">{{cite book |author=Sellnow, Les |url=https://archive.org/details/happytrailsyourc00sell/page/46 |title=Happy Trails: Your Complete Guide to Fun and Safe Trail Riding |publisher=Eclipse Press |year=2004 |isbn=1-58150-114-5 |page=[https://archive.org/details/happytrailsyourc00sell/page/46 46] |oclc=56493380}}</ref> Horses have excellent day and [[night vision]], but they have two-color, or [[Dichromacy|dichromatic vision]]; their [[color vision]] is somewhat like [[color blindness|red-green color blindness]] in humans, where certain colors, especially red and related colors, appear as a shade of green.<ref>{{cite journal |url= http://www.thehorse.com/viewarticle.aspx?ID=9670 |title= In Living Color |url-access= registration |access-date= 2007-07-27 |author= McDonnell, Sue |journal= The Horse |date= June 1, 2007 |archive-date= 2007-09-27 |archive-url= https://web.archive.org/web/20070927223341/http://www.thehorse.com/viewarticle.aspx?ID=9670 |url-status= live }}</ref>

Their [[Olfaction|sense of smell]], while much better than that of humans, is not quite as good as that of a dog. It is believed to play a key role in the social interactions of horses as well as detecting other key scents in the environment. Horses have two olfactory centers. The first system is in the nostrils and nasal cavity, which analyze a wide range of odors. The second, located under the nasal cavity, are the [[vomeronasal organ]]s, also called Jacobson's organs. These have a separate nerve pathway to the brain and appear to primarily analyze [[pheromone]]s.<ref name="Briggs smell">{{cite web |last=Briggs |first=Karen |title=Equine Sense of Smell |url=http://www.thehorse.com/articles/10055/equine-sense-of-smell |publisher=The Horse |access-date=2013-12-15 |date=2013-12-11 |archive-date=2018-02-01 |archive-url=https://web.archive.org/web/20180201013608/http://www.thehorse.com/articles/10055/equine-sense-of-smell |url-status=live }}</ref>

A horse's hearing is good,<ref name=Ensminger309/> and the [[Auricle (anatomy)|pinna]] of each ear can rotate up to 180°, giving the potential for 360° hearing without having to move the head.<ref>{{cite book |author=Myers, Jane |url=https://books.google.com/books?id=-gAgchKMXdkC |title=Horse Safe: A Complete Guide to Equine Safety |publisher=CSIRO Publishing |location=Collingwood, UK |year=2005 |isbn=0-643-09245-5 |oclc=65466652 |page=7 |access-date=2020-09-28 |archive-date=2023-03-20 |archive-url=https://web.archive.org/web/20230320223812/https://books.google.com/books?id=-gAgchKMXdkC |url-status=live }}</ref> Noise affects the behavior of horses and certain kinds of noise may contribute to stress—a 2013 study in the UK indicated that stabled horses were calmest in a quiet setting, or if listening to country or classical music, but displayed signs of nervousness when listening to jazz or rock music. This study also recommended keeping music under a volume of 21 [[decibel]]s.<ref name="Music">{{cite web |url=http://www.thehorse.com/articles/31229/music-genres-effect-on-horse-behavior-evaluated |title=Music Genre's Effect on Horse Behavior Evaluated |last=Lesté-Lasserre |first=Christa |date=January 18, 2013 |website=The Horse |publisher=Blood Horse Publications |access-date=23 January 2013 |archive-date=10 October 2017 |archive-url=https://web.archive.org/web/20171010200000/http://www.thehorse.com/articles/31229/music-genres-effect-on-horse-behavior-evaluated |url-status=live }}</ref> An Australian study found that stabled racehorses listening to talk radio had a higher rate of gastric ulcers than horses listening to music, and racehorses stabled where a radio was played had a higher overall rate of ulceration than horses stabled where there was no radio playing.<ref name="EquiNews">{{cite web |url=http://www.equinews.com/article/radios-causing-gastric-ulcers |title=Radios Causing Gastric Ulcers |author=Kentucky Equine Research Staff |date=February 15, 2010 |website=EquiNews |publisher=Kentucky Equine Research |access-date=23 January 2013 |archive-date=10 October 2017 |archive-url=https://web.archive.org/web/20171010200000/http://www.equinews.com/article/radios-causing-gastric-ulcers |url-status=live }}</ref>

Horses have a great sense of balance, due partly to their ability to feel their footing and partly to highly developed [[proprioception]]—the unconscious sense of where the body and limbs are at all times.<ref>{{cite web|url= http://www.thoroughbredtimes.com/horse-health/1998/October/17/True-horse-sense.aspx|title= True Horse Sense |access-date= 2008-07-08 |author= Thomas, Heather Smith |website= Thoroughbred Times |publisher= Thoroughbred Times Company |archive-date= 2012-11-02 |archive-url= https://web.archive.org/web/20121102020057/http://www.thoroughbredtimes.com/horse-health/1998/october/17/true-horse-sense.aspx |url-status= dead}}</ref> A horse's [[Somatosensory system|sense of touch]] is well-developed. The most sensitive areas are around the eyes, ears, and nose.<ref>{{cite web |url=http://www.unce.unr.edu/publications/files/ag/other/fs9829.pdf |title=Horse Handling and Riding Guidelines Part 1: Equine Senses |access-date=2008-07-09 |author1=Cirelli, Al Jr. |author2=Brenda Cloud |website=Cooperative Extension |page=4 |publisher=University of Nevada |archive-date=2015-09-08 |archive-url=https://web.archive.org/web/20150908031752/http://www.unce.unr.edu/publications/files/ag/other/fs9829.pdf |url-status=live }}</ref> Horses are able to sense contact as subtle as an insect landing anywhere on the body.<ref>{{cite book|author1= Hairston, Rachel|author2= Madelyn Larsen |title= The Essentials of Horsekeeping |publisher= Sterling Publishing Company, Inc. |year= 2004 |isbn= 0-8069-8817-7 |location= New York |url= https://archive.org/details/essentialsofhors00rach/page/77 |oclc= 53186526 |page= [https://archive.org/details/essentialsofhors00rach/page/77 77]}}</ref>

Horses have an advanced sense of taste, which allows them to sort through [[fodder]] and choose what they would most like to eat,<ref>[[#Miller|Miller]], p. 28</ref> and their [[Prehensility|prehensile]] lips can easily sort even small grains. Horses generally will not eat poisonous plants, however, there are exceptions; horses will occasionally eat toxic amounts of poisonous plants even when there is adequate healthy food.<ref>{{cite web |url= http://www.cvm.uiuc.edu/petcolumns/showarticle.cfm?id=16|title= Horse Pasture is No Place for Poisonous Plants |access-date=2008-07-09 |author= Gustavson, Carrie |website= Pet Column July 24, 2000 |publisher= University of Illinois |archive-url = https://web.archive.org/web/20070809051147/http://www.cvm.uiuc.edu/petcolumns/showarticle.cfm?id=16 |archive-date = August 9, 2007}}</ref>

===Movement===
{{Main|Horse gait|Trot|Canter|Ambling}}
<gallery>
File:Muybridge horse walking animated.gif|''Walk'' {{convert|5|–|8|km/h|mph|abbr=on}}
File:Trot animated.gif|''Trot'' {{convert|8|–|13|km/h|mph|abbr=on}}
File:Muybridge_horse_pacing_animated.gif|''Pace'' {{convert|8|–|13|km/h|mph|abbr=on}}
File:Canter animated.gif|''Canter'' {{convert|16|–|27|km/h|mph|abbr=on}}
File:Muybridge race horse animated.gif|''Gallop'' {{convert|40|–|48|km/h|mph|abbr=on}}, record: {{convert|70.76|km/h|abbr=on|sortable=on}}
</gallery>
All horses move naturally with four basic [[horse gait|gaits]]:<ref name=HorseGaits32>[[#Harris|Harris]], p. 32</ref>
*the four-beat [[Horse gait#Walk|walk]], which averages {{convert|6.4|km/h}}; 
*the two-beat [[Trot|trot or jog]] at {{convert|13|to|19|km/h}} (faster for [[harness racing]] horses);
*the [[Canter and gallop|canter or lope]], a three-beat gait that is {{convert|19|to|24|km/h}}; 
*the [[Canter and gallop|gallop]], which averages {{convert|40|to|48|km/h}},<ref name=Harris47>[[#Harris|Harris]], pp.&nbsp;47–49</ref> but the world record for a horse galloping over a short, sprint distance is {{convert|70.76|km/h}}.<ref name=guinness>{{cite web|title = Fastest speed for a race horse|website = Guinness World Records| date=14 May 2008 |access-date = 8 January 2013|url = http://www.guinnessworldrecords.com/world-records/fastest-speed-for-a-race-horse/|archive-date = 28 August 2017|archive-url = https://web.archive.org/web/20170828102736/http://www.guinnessworldrecords.com/world-records/fastest-speed-for-a-race-horse|url-status = live}}</ref> 
Besides these basic gaits, some horses perform a two-beat [[horse gait|pace]], instead of the trot.<ref name=HorseGaits50>[[#Harris|Harris]], p. 50</ref> There also are several four-beat '[[ambling]]' gaits that are approximately the speed of a trot or pace, though smoother to ride. These include the lateral [[Ambling#Rack|rack]], [[Ambling|running walk]], and [[tölt]] as well as the diagonal [[Ambling gait|fox trot]].<ref name="Lieberman">{{cite journal |author=Lieberman, Bobbie | year=2007 |title=Easy Gaited Horses|journal=Equus|issue= 359|pages=47–51}}</ref> Ambling gaits are often genetic in some breeds, known collectively as [[gaited horse]]s.<ref>{{cite journal |author=Equus Staff | year=2007 |title=Breeds that Gait|journal=Equus |issue= 359|pages=52–54}}</ref> These horses replace the trot with one of the ambling gaits<!--but some horses both trot and amble, can the Harris book support adding this?-->.<ref name=HorseGaits51>[[#Harris|Harris]], pp. 50–55</ref>

===Behavior===
{{Main|Horse behavior|Stable vices}}
[[File:Wiehern.ogg|thumb|right|Horse neigh]]
Horses are prey animals with a strong [[fight-or-flight response]]. Their first reaction to a threat is to startle and usually flee, although they will stand their ground and defend themselves when flight is impossible or if their young are threatened.<ref>{{cite web |url=http://www.extension.org/pages/23342/horse-fight-vs-flight-instinct |title=Horse Fight vs Flight Instinct |publisher=eXtension |date=2009-09-24 |access-date=2013-04-17 |archive-date=2013-05-15 |archive-url=https://web.archive.org/web/20130515125847/http://www.extension.org/pages/23342/horse-fight-vs-flight-instinct |url-status=dead }}</ref> They also tend to be curious; when startled, they will often hesitate an instant to ascertain the cause of their fright, and may not always flee from something that they perceive as non-threatening. Most light horse riding breeds were developed for speed, agility, alertness and endurance; natural qualities that extend from their wild ancestors. However, through selective breeding, some breeds of horses are quite docile, particularly certain draft horses.<ref name=Natural226>{{cite book|ref=McBane |author= McBane, Susan |title= A Natural Approach to Horse Management |publisher= Methuen |location= London |year= 1992|isbn= 0-413-62370-X |oclc= 26359746|pages= 226–228}}</ref>

[[File:Garranos fight.jpg|thumb|right|Horses fighting as part of herd dominance behaviour]]
Horses are [[herd animal]]s, with a clear hierarchy of rank, led by a dominant individual, usually a mare. They are also social creatures that are able to form companionship attachments to their own species and to other animals, including humans. They communicate in various ways, including vocalizations such as nickering or whinnying, mutual [[Social grooming|grooming]], and [[body language]]. Many horses will become difficult to manage if they are isolated, but with training, horses can learn to accept a human as a companion, and thus be comfortable away from other horses.<ref name=Ensminger305>[[#Ensminger|Ensminger]], pp. 305–309</ref> However, when confined with insufficient companionship, exercise, or stimulation, individuals may develop [[stable vices]], an assortment of bad habits, mostly [[Stereotypy (non-human)|stereotypies]] of psychological origin, that include wood chewing, wall kicking, "weaving" (rocking back and forth), and other problems.<ref name=Prince214>{{cite book|author1= Prince, Eleanor F. |author2= Gaydell M. Collier |title= Basic Horsemanship: English and Western |publisher= Doubleday |location= New York |year= 1974|isbn= 0-385-06587-6|oclc= 873660|pages= [https://archive.org/details/basichorsemanshi00prin/page/214 214–223]|url= https://archive.org/details/basichorsemanshi00prin/page/214}}</ref>

====Intelligence and learning====
Studies have indicated that horses perform a number of [[Cognition|cognitive]] tasks on a daily basis, meeting mental challenges that include [[foraging|food procurement]] and identification of individuals within a [[Social structure|social system]]. They also have good [[Spatial visualization ability|spatial discrimination]] abilities.<ref name=Hanggi>{{cite web |url=http://www.horsetalk.co.nz/features/horseintelligence-119.shtml |title=Understanding horse intelligence |author=Clarkson, Neil |date=2007-04-16 |access-date=2008-09-16 |website=Horsetalk 2007 |publisher=Horsetalk |archive-date=2013-01-24 |archive-url=https://web.archive.org/web/20130124164951/http://horsetalk.co.nz/2012/10/11/understanding-horse-intelligence/ |url-status=live }}</ref> They are naturally curious and apt to investigate things they have not seen before.<ref>{{Cite book |title=True horsemanship through feel |last=Dorrance |first=Bill |publisher=The Lion Press|year=1999|isbn=1-58574-321-6|location=Guilford, CT |pages=1}}</ref> Studies have assessed equine intelligence in areas such as [[problem solving]], speed of learning, and [[memory]]. Horses excel at simple learning, but also are able to use more advanced cognitive abilities that involve [[categorization]] and [[concept learning]]. They can learn using [[habituation]], [[Desensitization (psychology)|desensitization]], [[classical conditioning]], and [[operant conditioning]], and positive and negative [[reinforcement]].<ref name=Hanggi/> One study has indicated that horses can differentiate between "more or less" if the quantity involved is less than four.<ref name="count">{{cite web |url=http://www.thehorse.com/ViewArticle.aspx?ID=15396 |title=Horses Demonstrate Ability to Count in New Study |author=Lesté-Lasserre, Christa |access-date=2009-12-06 |website=The Horse |archive-date=2016-01-01 |archive-url=https://web.archive.org/web/20160101025607/http://www.thehorse.com/articles/24628/horses-demonstrate-ability-to-count-in-new-study |url-status=live }}</ref>

Domesticated horses may face greater mental challenges than wild horses, because they live in artificial environments that prevent [[instinct]]ive behavior whilst also learning tasks that are not natural.<ref name=Hanggi/> Horses are animals of [[habit]] that respond well to regimentation, and respond best when the same routines and techniques are used consistently. One trainer believes that "intelligent" horses are reflections of intelligent trainers who effectively use response conditioning techniques and positive reinforcement to train in the style that best fits with an individual animal's natural inclinations.<ref>{{cite web |url=http://cs.bloodhorse.com/blogs/nicanor/archive/2008/06/17/equine-iq-what-big-brown-couldn-t-tell-you-and-mr-ed-kept-to-himself.aspx |title=What Big Brown Couldn't Tell You and Mr. Ed Kept to Himself (part 1) |author=Coarse, Jim |date=2008-06-17 |access-date=2008-09-16 |website=The Blood Horse |archive-date=2012-05-21 |archive-url=https://web.archive.org/web/20120521084441/http://cs.bloodhorse.com/blogs/nicanor/archive/2008/06/17/equine-iq-what-big-brown-couldn-t-tell-you-and-mr-ed-kept-to-himself.aspx |url-status=live }}</ref>

====Temperament====<!--[[cold blooded (horse)]] and [[hot blooded (horse)]] redirect to this section so if the section name is changed change the redirects-->
{{Main|Draft horse|Warmblood|Oriental horse|Hot-blooded horse}}
Horses are [[mammal]]s. As such, they are [[warm-blooded]], or [[endotherm]]ic creatures, as opposed to cold-blooded, or [[poikilotherm]]ic animals. However, these words have developed a separate meaning in the context of equine terminology, used to describe temperament, not [[Thermoregulation|body temperature]]. For example, the "[[Hot-blooded horse|hot-bloods]]", such as many [[horse racing|race horses]], exhibit more sensitivity and energy,<ref name="Belknap255">[[#Belknap|Belknap]], p. 255</ref> while the "cold-bloods", such as most [[draft horse|draft breeds]], are quieter and calmer.<ref name="Belknap112">[[#Belknap|Belknap]], p. 112</ref> Sometimes "hot-bloods" are classified as "light horses" or "riding horses",<ref name="Ensminger71">[[#Ensminger|Ensminger]], pp. 71–73</ref> with the "cold-bloods" classified as "draft horses" or "work horses".<ref name="Ensminger84">[[#Ensminger|Ensminger]], p. 84</ref>

[[File:Brockhaus and Efron Encyclopedic Dictionary b35 043-0.jpg|thumb|upright=1.5|Illustration of assorted breeds; slim, light hotbloods, medium-sized warmbloods and draft and pony-type coldblood breeds|alt=a sepia-toned engraving from an old book, showing 11 horses of different breeds and sizes in nine different illustrations]]
"Hot blooded" breeds include "[[oriental horse]]s" such as the [[Akhal-Teke]], [[Arabian horse]], [[Barb horse|Barb]], and now-extinct [[Turkoman horse]], as well as the [[Thoroughbred]], a breed developed in England from the older oriental breeds.<ref name=Belknap255/> Hot bloods tend to be spirited, bold, and learn quickly. They are bred for agility and speed.<ref name=Catalog18/> They tend to be physically refined—thin-skinned, slim, and long-legged.<ref>{{cite book |author=DeFilippis, Chris |title=The Everything Horse Care Book |publisher=Adams Media |location= Avon, MA |year=2006 |isbn=978-1-59337-530-0 |oclc=223814651|page=4}}</ref> The original oriental breeds were brought to Europe from the Middle East and North Africa when European breeders wished to infuse these traits into racing and light [[cavalry]] horses.<ref name=Whitaker43>[[#Whitaker|Whitaker]], p. 43</ref><ref name=Whitaker194>[[#Whitaker|Whitaker]], pp. 194–197</ref>

Muscular, heavy [[draft horse]]s are known as "cold bloods." They are bred not only for strength, but also to have the calm, patient temperament needed to pull a plow or a heavy carriage full of people.<ref name=Belknap112/> They are sometimes nicknamed "gentle giants".<ref name=Catalog15>[[#Price|Price]], p. 15</ref> Well-known draft breeds include the [[Belgian Draught|Belgian]] and the [[Clydesdale horse|Clydesdale]].<ref name=Catalog15/> Some, like the [[Percheron]], are lighter and livelier, developed to pull carriages or to plow large fields in drier climates.<ref name=Guide87>[[#Bongianni|Bongianni]], entry 87</ref> Others, such as the [[Shire horse|Shire]], are slower and more powerful, bred to plow fields with heavy, clay-based soils.<ref name=Ens124>[[#Ensminger|Ensminger]], pp. 124–125</ref> The cold-blooded group also includes some pony breeds.<ref name="Bennett7" />

"[[Warmblood]]" breeds, such as the [[Trakehner]] or [[Hanoverian horse|Hanoverian]], developed when European carriage and [[horses in warfare|war horses]] were crossed with Arabians or Thoroughbreds, producing a riding horse with more refinement than a draft horse, but greater size and milder temperament than a lighter breed.<ref>[[#Edwards|Edwards]], pp. 122–123</ref> Certain [[pony]] breeds with warmblood characteristics have been developed for smaller riders.<ref>Examples are the [[Australian Riding Pony]] and the [[Connemara pony|Connemara]], see [[#Edwards|Edwards]], pp. 178–179, 208–209</ref> Warmbloods are considered a "light horse" or "riding horse".<ref name=Ensminger71/>

Today, the term "Warmblood" refers to a specific subset of [[sport horse]] breeds that are used for competition in [[dressage]] and [[show jumping]].<ref name=Lyons231>{{cite book |author=Price, Steven D. |author2=Shiers, Jessie |title=The Lyons Press Horseman's Dictionary |publisher=Lyons Press |location=Guilford, CT |year=2007 |edition=Revised |isbn=978-1-59921-036-0|page=231}}</ref> Strictly speaking, the term "[[Warmblood|warm blood]]" refers to any [[crossbreeding|cross]] between cold-blooded and hot-blooded breeds.<ref name=Belknap523>[[#Belknap|Belknap]], p. 523</ref> Examples include breeds such as the [[Irish Draught]] or the [[Cleveland Bay]]. The term was once used to refer to breeds of light riding horse other than Thoroughbreds or Arabians, such as the [[Morgan horse]].<ref name=Catalog18>[[#Price|Price]], p. 18</ref>

====Sleep patterns====
{{See also|Horse behavior#Sleep patterns|l1=Horse sleep patterns|Sleep in non-human animals|l2=Sleep in non-humans}}
[[File:Biandintz eta zaldiak - modified2.jpg|thumb|left|When horses lie down to sleep, others in the herd remain standing, awake, or in a light doze, keeping watch.|alt=Two horses in a pasture, one is standing beside the other that is laying down.]]
Horses are able to sleep both standing up and lying down. In an adaptation from life in the wild, horses are able to enter light sleep by using a "[[stay apparatus]]" in their legs, allowing them to doze without collapsing.<ref>{{cite web|url= http://equisearch.com/horses_care/health/behavior/eqzzz629/ |title= How Horses Sleep |access-date= 2007-03-23 |author= Pascoe, Elaine |website= Equisearch.com |url-status=dead |archive-url= https://web.archive.org/web/20070927193341/http://equisearch.com/horses_care/health/behavior/eqzzz629/ |archive-date= 2007-09-27}}</ref> Horses sleep better when in groups because some animals will sleep while others stand guard to watch for predators. A horse kept alone will not sleep well because its [[instinct]]s are to keep a constant eye out for danger.<ref name="Horse sleep pt. 2"/>

Unlike humans, horses do not sleep in a solid, unbroken period of time, but take many short periods of rest. Horses spend four to fifteen hours a day in standing rest, and from a few minutes to several hours lying down. Total sleep time in a 24-hour period may range from several minutes to a couple of hours,<ref name="Horse sleep pt. 2">{{cite web |url= http://equisearch.com/horses_care/health/behavior/eqpowernap1771/ |title= How Horses Sleep, Pt. 2&nbsp;– Power Naps |access-date= 2007-03-23|author= Pascoe, Elaine |website= Equisearch.com |date= 2002-03-12 |url-status=dead |archive-url= https://web.archive.org/web/20070927193158/http://equisearch.com/horses_care/health/behavior/eqpowernap1771/ |archive-date= 2007-09-27}}</ref> mostly in short intervals of about 15&nbsp;minutes each.<ref name=Ensminger310>[[#Ensminger|Ensminger]], p. 310.</ref> The average sleep time of a domestic horse is said to be 2.9 hours per day.<ref>{{cite journal|title=40 Winks? |author=Holland, Jennifer S. |journal=National Geographic |volume=220 |date=July 2011 |issue=1}}</ref>

Horses must lie down to reach [[Rapid eye movement sleep|REM sleep]]. They only have to lie down for an hour or two every few days to meet their minimum REM sleep requirements.<ref name="Horse sleep pt. 2"/> However, if a horse is never allowed to lie down, after several days it will become sleep-deprived, and in rare cases may suddenly collapse because it slips, involuntarily, into REM sleep while still standing.<ref>{{cite web|url= http://equisearch.com/horses_care/health/behavior/sleepdisorder_121506/ |title= Equine Sleep Disorder Videos |access-date= 2007-03-23 |author= EQUUS Magazine Staff |website= Equisearch.com |url-status=dead |archive-url= https://web.archive.org/web/20070510051620/http://equisearch.com/horses_care/health/behavior/sleepdisorder_121506/ |archive-date= 2007-05-10}}</ref> This condition differs from [[narcolepsy]], although horses may also suffer from that disorder.<ref name="Smith">{{cite book |author=Smith, BP |title=Large Animal Internal Medicine |publisher=Mosby |location=St. Louis, MO |year=1996 |edition=Second |isbn=0-8151-7724-0 |oclc=33439780|pages= 1086–1087}}</ref>

==Taxonomy and evolution==
[[File:Equine evolution.jpg|thumb|upright=1.5|Diagram of evolution in horses showing size development, biometrical changes in the cranium and reduction of toes (left forefoot)]]
{{Main|Evolution of the horse|Equus (genus)|Equidae}}
The horse [[Adaptation|adapted]] to survive in areas of wide-open terrain with sparse vegetation, surviving in an [[ecosystem]] where other large grazing animals, especially [[ruminant]]s, could not.<ref name="Budiansky">{{cite book|author= Budiansky, Stephen |title= The Nature of Horses |publisher= Free Press |location= New York |year= 1997 |isbn= 0-684-82768-9 |oclc= 35723713 |page= [https://archive.org/details/natureofhorsesex00budi/page/31 31] |url=https://archive.org/details/natureofhorsesex00budi/page/31}}</ref> Horses and other equids are [[odd-toed ungulate]]s of the [[Order (biology)|order]] [[Perissodactyla]], a group of mammals dominant during the [[Tertiary]] period. In the past, this order contained 14&nbsp;[[Family (biology)|families]], but only three—[[Equidae]] (the horse and related species), [[Tapiridae]] (the [[tapir]]), and [[Rhinocerotidae]] (the [[rhinoceros]]es)—have survived to the present day.<ref>{{cite web |url= http://animaldiversity.ummz.umich.edu/site/accounts/information/Perissodactyla.html |title= Order Perissodactyla |access-date= 2008-07-09 |author= Myers, Phil |website= Animal Diversity Web |publisher= University of Michigan |archive-date= 2013-01-22 |archive-url= https://web.archive.org/web/20130122033502/http://animaldiversity.ummz.umich.edu/site/accounts/information/Perissodactyla.html |url-status= live }}</ref>

The earliest known member of the family Equidae was the ''[[Hyracotherium]]'', which lived between 45 and 55&nbsp;million years ago, during the [[Eocene]] period. It had 4&nbsp;toes on each front foot, and 3&nbsp;toes on each back foot.<ref>{{cite web|url= http://www.flmnh.ufl.edu/fhc/hyraco1.htm|title= Hyracotherium|access-date= 2008-07-09|website= Fossil Horses in Cyberspace|publisher= [[Florida Museum of Natural History]]|archive-date= 2013-01-31|archive-url= https://web.archive.org/web/20130131105733/http://www.flmnh.ufl.edu/fhc/hyraco1.htm|url-status= live}}</ref> The extra toe on the front feet soon disappeared with the ''[[Mesohippus]]'', which lived 32 to 37&nbsp;million years ago.<ref>{{cite web|url= http://www.flmnh.ufl.edu/fhc/mesoh1.htm|title= Mesohippus|access-date= 2008-07-09|website= Fossil Horses in Cyberspace|publisher= Florida Museum of Natural History|archive-date= 2013-01-22|archive-url= https://web.archive.org/web/20130122033356/http://www.flmnh.ufl.edu/fhc/mesoh1.htm|url-status= live}}</ref> Over time, the extra side toes shrank in size until they vanished. All that remains of them in modern horses is a set of small [[Vestigiality|vestigial]] bones on the leg below the knee,<ref name=Natural>{{cite web |url= http://www.amnh.org/exhibitions/horse/?section=evolution&page=evolution_b |title= The Evolution of Horses |access-date= 2008-07-09 |website= The Horse |publisher= American Museum of Natural History |archive-date= 2013-01-28 |archive-url= https://web.archive.org/web/20130128123829/http://www.amnh.org/exhibitions/past-exhibitions/horse |url-status= live }}</ref> known informally as splint bones.<ref>[[#Miller|Miller]], p. 20</ref> Their legs also lengthened as their toes disappeared until they were a hooved animal capable of running at great speed.<ref name=Natural/> By about 5&nbsp;million years ago, the modern ''Equus'' had evolved.<ref name=Florida>{{cite web |url= http://www.flmnh.ufl.edu/fhc/equus1.htm |title= Equus |access-date= 2008-07-09 |website= Fossil Horses in Cyberspace |publisher= Florida Museum of Natural History |archive-date= 2013-01-22 |archive-url= https://web.archive.org/web/20130122033350/http://www.flmnh.ufl.edu/fhc/equus1.htm |url-status= live }}</ref> Equid teeth also evolved from browsing on soft, tropical plants to adapt to browsing of drier plant material, then to grazing of tougher plains grasses. Thus proto-horses changed from leaf-eating forest-dwellers to grass-eating inhabitants of semi-arid regions worldwide, including the [[steppe]]s of Eurasia and the [[Great Plains]] of North America.

By about 15,000 years ago, ''Equus ferus'' was a widespread [[holarctic]] species. Horse bones from this time period, the late [[Pleistocene]], are found in Europe, Eurasia, [[Beringia]], and North America.<ref name = Weinstock>{{cite journal|last1=Weinstock|first1=J.|year=2005|title=Evolution, Systematics, and Phylogeography of Pleistocene Horses in the New World: A Molecular Perspective |journal=[[PLOS Biology]] |pmid=15974804 |volume=3 |issue=8 |pmc=1159165 |pages=e241 | doi=10.1371/journal.pbio.0030241 |display-authors=1 |last2=Willerslev |first2=Eske |last3=Sher |first3=Andrei |last4=Tong |first4=Wenfei |last5=Ho |first5=Simon Y.W. |last6=Rubenstein |first6=Dan |last7=Storer |first7=John |last8=Burns |first8=James |last9=Martin |first9=Larry |doi-access=free }}</ref> Yet between 10,000 and 7,600 years ago, the horse became extinct in North America.<ref name = VilaWidespreadOrigins>{{cite journal|last=Vila |first=C.|year=2001|title=Widespread Origins of Domestic Horse Lineages |journal=[[Science (journal)|Science]] |volume=291 |doi=10.1126/science.291.5503.474 |url=http://www.uky.edu/Ag/Horsemap/Maps/VILA.PDF |pages=474–477 |pmid=11161199 |issue=5503 |display-authors=etal |bibcode=2001Sci...291..474V |access-date=2009-03-17 |archive-date=2012-10-13 |archive-url=https://web.archive.org/web/20121013082210/http://www.uky.edu/Ag/Horsemap/Maps/VILA.PDF |url-status=dead}}</ref><ref name = IberianOrigins>{{cite journal|last=Luís |first= Cristina |year=2006 |title=Iberian Origins of New World Horse Breeds |journal=Quaternary Science Reviews |volume=97 |issue=2 | pages=107–113 |doi=10.1093/jhered/esj020 |pmid=16489143 |display-authors=etal |doi-access=free}}</ref><ref name=Haile>{{cite journal|title=Ancient DNA reveals late survival of mammoth and horse in interior Alaska |doi=10.1073/pnas.0912510106 |author=Haile, James |journal=PNAS |year=2009 |volume=106|issue= 52 |pages=22352–22357 |display-authors=1 |last2=Froese |first2=D. G. |last3=MacPhee |first3=R. D. E. |last4=Roberts |first4=R. G. |last5=Arnold |first5=L. J. |last6=Reyes |first6=A. V. |last7=Rasmussen |first7=M. |last8=Nielsen |first8=R. |last9=Brook |first9=B. W. |pmid=20018740 |pmc=2795395 |bibcode=2009PNAS..10622352H |doi-access=free}}</ref> The reasons for this extinction are not fully known, but one theory notes that extinction in North America paralleled human arrival.<ref name = Buck>{{cite journal |last=Buck |first=Caitlin E. |author2=Bard, Edouard |year=2007 |title=A calendar chronology for Pleistocene mammoth and horse extinction in North America based on Bayesian radiocarbon calibration |journal=Quaternary Science Reviews |volume=26 |issue=17–18 |doi=10.1016/j.quascirev.2007.06.013 |pages=2031–2035 |bibcode=2007QSRv...26.2031B |url=https://zenodo.org/record/886512 |access-date=2017-09-06 |archive-date=2018-11-06 |archive-url=https://web.archive.org/web/20181106193405/https://zenodo.org/record/886512 |url-status=live }}</ref> Another theory points to [[climate change]], noting that approximately 12,500 years ago, the grasses characteristic of a [[steppe]] ecosystem gave way to shrub [[tundra]], which was covered with unpalatable plants.<ref name="LeQuire">{{cite web | url=http://www.thehorse.com/ViewArticle.aspx?ID=4849 | author=LeQuire, Elise | title=No Grass, No Horse | publisher=The Horse | url-access=registration | date=2004-01-04 | access-date=2009-06-08 | archive-date=2013-01-09 | archive-url=https://web.archive.org/web/20130109101503/http://www.thehorse.com/articles/14327/no-grass-no-horse | url-status=live }}</ref>

===Wild species surviving into modern times===
[[File:France Lozère Causse Méjean Chevaux de Przewalski 20.jpg|thumb|A small herd of Przewalski's Horses|alt=Three tan-colored horses with upright manes. Two horses nip and paw at each other, while the third moves towards the camera. They stand in an open, rocky grassland, with forests in the distance.]]
{{Main|Wild horse}}
A truly [[wild horse]] is a species or subspecies with no ancestors that were ever successfully domesticated. Therefore, most "wild" horses today are actually [[feral horse]]s, animals that escaped or were turned loose from domestic herds and the descendants of those animals.<ref name=Olsen46>{{cite book|author= Olsen, Sandra L.|chapter= Horse Hunters of the Ice Age |title= Horses Through Time |edition= First |publisher= Roberts Rinehart Publishers |location= Boulder, CO |year= 1996 |isbn= 1-57098-060-8 |oclc=36179575 |page= [https://archive.org/details/horsesthroughtim00olse/page/46 46] |chapter-url= https://archive.org/details/horsesthroughtim00olse/page/46}}</ref> Only two wild subspecies, the [[tarpan]] and the [[Przewalski's horse]], survived into recorded history and only the latter survives today.

The [[Przewalski's horse]] (''Equus ferus przewalskii''), named after the Russian explorer [[Nikolai Przhevalsky]], is a rare Asian animal. It is also known as the Mongolian wild horse; [[Mongolia]]n people know it as the ''taki'', and the [[Kyrgyz people]] call it a ''kirtag''. The subspecies was presumed extinct in the wild between 1969 and 1992, while a small breeding population survived in zoos around the world. In 1992, it was reestablished in the wild by the conservation efforts of numerous zoos.<ref>{{cite web|url= http://www.zsl.org/about-us/media/press-releases/null,1790,PR.html |title= An extraordinary return from the brink of extinction for world's last wild horse |date= 2005-12-19 |access-date= 2012-06-06 |website= ZSL Press Releases |publisher= Zoological Society of London |url-status=dead |archive-url= https://web.archive.org/web/20130516230420/http://www.zsl.org/about-us/media/press-releases/null,1790,PR.html |archive-date= 2013-05-16}}</ref> Today, a small wild breeding population exists in Mongolia.<ref>{{cite web|url= http://www.treemail.nl/takh/ |title= Home |access-date= 2008-04-03 |publisher= The Foundation for the Preservation and Protection of the Przewalski Horse |archive-url= https://web.archive.org/web/20171010200000/http://www.treemail.nl/takh/ |archive-date=2017-10-10 |url-status=dead}}</ref><ref name=Dohner298>[[#Dohner|Dohner]], pp. 298–299</ref> There are additional animals still maintained at zoos throughout the world.

Their status as a truly wild horse was called into question when domestic horses of the 5,000-year-old [[Botai culture]] of Central Asia were found more closely related to Przewalski's horses than to ''E. f. caballus''. The study raised the possibility that modern Przewalski's horses could be the feral descendants of the domestic Botai horses. However, it remains possible that both the Botai horses and the modern Przewalski's horses descend separately from the same ancient wild Przewalski's horse population.<ref name="Pennisi">{{cite web |author=Pennisi, Elizabeth |author-link=Elizabeth Pennisi |title=Ancient DNA upends the horse family tree |website=sciencemag.org |date=22 February 2018 |url=https://www.science.org/content/article/ancient-dna-upends-horse-family-tree |access-date=30 June 2022 |archive-date=21 September 2022 |archive-url=https://web.archive.org/web/20220921222121/https://www.science.org/content/article/ancient-dna-upends-horse-family-tree |url-status=live }}</ref><ref name=Orlando>{{Cite journal |last1=Orlando |first1=Ludovic |last2=Outram |first2=Alan K. |last3=Librado| first3=Pablo |last4=Willerslev |first4=Eske |last5=Zaibert |first5=Viktor |last6=Merz |first6=Ilja |last7=Merz |first7=Victor |last8=Wallner |first8=Barbara |last9=Ludwig |first9=Arne |date=2018-04-06 |df=dmy-all |title=Ancient genomes revisit the ancestry of domestic and Przewalski's horses |journal=Science |language=en |volume=360 |issue=6384 |pages=111–114 |doi=10.1126/science.aao3297 |issn=0036-8075 |pmid=29472442|bibcode=2018Sci...360..111G |doi-access=free|hdl=10871/31710 |hdl-access=free }}</ref><ref>{{cite web|url=https://arstechnica.com/science/2018/02/ancient-dna-rules-out-archeologists-best-bet-for-horse-domestication/|date=February 25, 2018|title=Ancient DNA rules out archeologists' best bet for horse domestication|publisher=[[ArsTechnica]]|access-date=24 June 2020|archive-date=25 June 2020|archive-url=https://web.archive.org/web/20200625064751/https://arstechnica.com/science/2018/02/ancient-dna-rules-out-archeologists-best-bet-for-horse-domestication/|url-status=live}}</ref>

The [[tarpan]] or European wild horse (''Equus ferus ferus'') was found in Europe and much of Asia. It survived into the historical era, but became [[Extinction|extinct]] in 1909, when the last captive died in a Russian zoo.<ref name=Dohner300>[[#Dohner|Dohner]], p. 300</ref> Thus, the genetic line was lost. Attempts have been made to recreate the tarpan,<ref name=Dohner300/><ref name=OSU>{{cite web|url=http://www.ansi.okstate.edu/breeds/horses/tarpan/ |title=Tarpan |publisher=Oklahoma State University |website=Breeds of Livestock |access-date=2009-01-13 |archive-url=https://web.archive.org/web/20090116022102/http://www.ansi.okstate.edu/breeds/horses/TARPAN/ |archive-date=2009-01-16}}</ref><ref>{{cite journal |url=https://news.google.com/newspapers?nid=894&dat=20020621&id=YiALAAAAIBAJ&pg=6481,3069519 |journal=The Daily Courier |date=June 21, 2002 |access-date=2009-10-21 |title=Ponies from the past?: Oregon couple revives prehistoric Tarpan horses |archive-date=2021-04-17 |archive-url=https://web.archive.org/web/20210417182639/https://news.google.com/newspapers?nid=894&dat=20020621&id=YiALAAAAIBAJ&pg=6481,3069519 |url-status=live }}</ref> which resulted in horses with outward physical similarities, but nonetheless descended from domesticated ancestors and not true wild horses.

Periodically, populations of horses in isolated areas are speculated to be [[Relict (biology)|relict]] populations of wild horses, but generally have been proven to be feral or domestic. For example, the [[Riwoche horse]] of Tibet was proposed as such,<ref name=Dohner298/> but testing did not reveal genetic differences from domesticated horses.<ref name=Tibet>{{cite book |title=Tibet: The Secret Continent |author=Peissel, Michel |year=2002 |publisher=Macmillan |isbn=0-312-30953-8 |url=https://books.google.com/books?id=6sFWvuBug8IC&pg=PA36 |page=36 |access-date=2020-09-28 |archive-date=2023-03-20 |archive-url=https://web.archive.org/web/20230320223812/https://books.google.com/books?id=6sFWvuBug8IC&pg=PA36 |url-status=live }}</ref> Similarly, the [[Sorraia]] of Portugal was proposed as a direct descendant of the [[Tarpan]] on the basis of shared characteristics,<ref name="Royo">{{cite journal|author1=Royo, L.J. |author2=Álvarez, I. |author3=Beja-Pereira, A. |author4=Molina, A. |author5=Fernández, I. |author6=Jordana, J. |author7=Gómez, E. |author8=Gutiérrez, J. P. |author9=Goyache, F. |year=2005 |title=The Origins of Iberian Horses Assessed via Mitochondrial DNA |journal=Journal of Heredity |volume=96 |issue=6 |pages=663–669 |doi=10.1093/jhered/esi116|pmid=16251517|doi-access=free}}<!--|access-date=2008-12-15--></ref><ref name=Edwards>[[#Edwards|Edwards]], pp. 104–105</ref> but genetic studies have shown that the Sorraia is more closely related to other horse breeds, and that the outward similarity is an unreliable measure of relatedness.<ref name=Royo/><ref name=Lira/>

===Other modern equids===
{{Main|Equus (genus)}}
Besides the horse, there are six other species of [[genus]] ''Equus'' in the Equidae [[family (biology)|family]]. These are the ass or [[donkey]], ''Equus asinus''; the [[mountain zebra]], ''Equus zebra''; [[plains zebra]], ''Equus quagga''; [[Grévy's zebra]], ''Equus grevyi''; the [[kiang]], ''Equus kiang''; and the [[onager]], ''Equus hemionus''.<ref>{{cite web |url=https://www.departments.bucknell.edu/biology/resources/msw3/browse.asp?id=14100020 |title=Equus hemionus |author=Pallas |year=1775 |website=Wilson & Reeder's mammal species of the world |publisher=[[Bucknell University]] |access-date=September 1, 2010 |archive-date=September 26, 2013 |archive-url=https://web.archive.org/web/20130926213002/http://www.departments.bucknell.edu/biology/resources/msw3/browse.asp?id=14100020 |url-status=live }}</ref>

Horses can [[crossbreed]] with other members of their genus. The most common [[Hybrid (biology)|hybrid]] is the [[mule]], a cross between a "jack" (male donkey) and a [[mare]]. A related hybrid, a [[hinny]], is a cross between a stallion and a "jenny" (female donkey).<ref>{{cite web|url= http://www.britishmulesociety.org.uk/|title= Mule Information |access-date= 2008-07-10 |website= BMS Website |publisher= British Mule Society |archive-url= https://web.archive.org/web/20171010200000/http://www.britishmulesociety.org.uk/ |archive-date= 2017-10-10 |url-status= dead}}</ref> Other hybrids include the [[zorse]], a cross between a zebra and a horse.<ref>{{cite news|url=http://news.bbc.co.uk/2/hi/science/nature/1408717.stm|title=Zebra hybrid is cute surprise|date=June 26, 2001|access-date=2010-02-06|work=BBC News|archive-date=2017-06-14|archive-url=https://web.archive.org/web/20170614032715/http://news.bbc.co.uk/2/hi/science/nature/1408717.stm|url-status=live}}</ref> With rare exceptions, most hybrids are [[infertility|sterile]] and cannot reproduce.<ref>{{cite news |url=https://www.npr.org/templates/story/story.php?storyId=12260255 |title=Befuddling Birth: The Case of the Mule's Foal |access-date=2008-08-16 |newspaper=NPR.org |publisher=National Public Radio |archive-date=2008-12-06 |archive-url=https://web.archive.org/web/20081206052236/http://www.npr.org/templates/story/story.php?storyId=12260255 |url-status=live }}</ref>

==Domestication and history==
{{Main|History of horse domestication theories|Domestication of the horse}}{{Anchor|Domestication}}[[File:Bhimbetka rock paintng1.jpg|thumb|[[Bhimbetka rock shelters|Bhimbetka]] rock painting showing a man riding on a horse, India]]
Domestication of the horse most likely took place in central Asia prior to 3500 BCE. Two major sources of information are used to determine where and when the horse was first domesticated and how the domesticated horse spread around the world. The first source is based on [[Paleontology|palaeological]] and archaeological discoveries; the second source is a comparison of DNA obtained from modern horses to that from bones and teeth of ancient horse remains.

The horse was domesticated by the Indo-Europeans in Eurasia.<ref>{{Cite journal |last1=Librado |first1=Pablo |last2=Khan |first2=Naveed |last3=Fages |first3=Antoine |last4=Kusliy |first4=Mariya A. |last5=Suchan |first5=Tomasz |last6=Tonasso-Calvière |first6=Laure |last7=Schiavinato |first7=Stéphanie |last8=Alioglu |first8=Duha |last9=Fromentier |first9=Aurore |last10=Perdereau |first10=Aude |last11=Aury |first11=Jean-Marc |last12=Gaunitz |first12=Charleen |last13=Chauvey |first13=Lorelei |last14=Seguin-Orlando |first14=Andaine |last15=Der Sarkissian |first15=Clio |date=2021 |title=The origins and spread of domestic horses from the Western Eurasian steppes |journal=Nature |language=en |volume=598 |issue=7882 |pages=634–640 |doi=10.1038/s41586-021-04018-9 |pmid=34671162 |issn=1476-4687|pmc=8550961 |bibcode=2021Natur.598..634L }}</ref><ref>{{Cite journal |last=Chakravarthy |first=R. S. |date=1975 |title=Ṛgvedic India, a Centre of Domestication of the Horse |url=https://www.jstor.org/stable/41691555 |journal=Annals of the Bhandarkar Oriental Research Institute |volume=56 |issue=1/4 |pages=129–139 |jstor=41691555 |issn=0378-1143}}</ref> The earliest archaeological evidence for the [[domestication of the horse]] comes from sites in [[Ukraine]] and [[Kazakhstan]], dating to approximately 4000–3500 BCE.<ref>{{Cite journal | pmid = 19265018| year = 2009| last1 = Outram| first1 = A. K.| title = The earliest horse harnessing and milking| journal = Science| volume = 323| issue = 5919| pages = 1332–1335| last2 = Stear| first2 = N. A.| last3 = Bendrey| first3 = R| last4 = Olsen| first4 = S| last5 = Kasparov| first5 = A| last6 = Zaibert| first6 = V| last7 = Thorpe| first7 = N| last8 = Evershed| first8 = R. P.| doi = 10.1126/science.1168594| bibcode = 2009Sci...323.1332O| s2cid = 5126719}}</ref><ref>{{cite book |author= Matossian, Mary Kilbourne |url= https://books.google.com/books?id=LkRATLisN0sC&pg=PA43 |title= Shaping World History: Breakthroughs in Ecology, Technology, Science, and Politics |publisher= M.E. Sharpe |location= Armonk, NY |year= 1997 |isbn= 0-585-02397-2 |oclc= 156944228 |page= 43 |access-date= 2020-09-28 |archive-date= 2023-03-20 |archive-url= https://web.archive.org/web/20230320223830/https://books.google.com/books?id=LkRATLisN0sC&pg=PA43 |url-status= live }}</ref><ref>{{cite news|title=Horsey-aeology, Binary Black Holes, Tracking Red Tides, Fish Re-evolution, Walk Like a Man, Fact or Fiction|url=http://www.cbc.ca/quirks/episode/2009/03/07/horsey-aeology-binary-black-holes-tracking-red-tides-fish-re-evolution-walk-like-a-man-fact-or-ficti/|work=Quirks and Quarks Podcast with Bob Macdonald|publisher=[[CBC Radio]]|date=2009-03-07|access-date=2010-09-18|archive-date=2014-10-07|archive-url=https://web.archive.org/web/20141007100308/http://www.cbc.ca/quirks/episode/2009/03/07/horsey-aeology-binary-black-holes-tracking-red-tides-fish-re-evolution-walk-like-a-man-fact-or-ficti/|url-status=live}}</ref>  However the horses domesticated at the Botai culture in Kazakhstan were Przewalski's horses and not the ancestors of modern horses.<ref>{{Cite journal |last1=Taylor |first1=William Timothy Treal |last2=Barrón-Ortiz |first2=Christina Isabelle |date=2021-04-02 |title=Rethinking the evidence for early horse domestication at Botai |journal=Scientific Reports |language=en |volume=11 |issue=1 |pages=7440 |doi=10.1038/s41598-021-86832-9 |pmid=33811228 |pmc=8018961 |bibcode=2021NatSR..11.7440T |issn=2045-2322}}</ref><ref>{{Cite journal |last1=Librado |first1=Pablo |last2=Khan |first2=Naveed |last3=Fages |first3=Antoine |last4=Kusliy |first4=Mariya A. |last5=Suchan |first5=Tomasz |last6=Tonasso-Calvière |first6=Laure |last7=Schiavinato |first7=Stéphanie |last8=Alioglu |first8=Duha |last9=Fromentier |first9=Aurore |last10=Perdereau |first10=Aude |last11=Aury |first11=Jean-Marc |last12=Gaunitz |first12=Charleen |last13=Chauvey |first13=Lorelei |last14=Seguin-Orlando |first14=Andaine |last15=Der Sarkissian |first15=Clio |date=2021 |title=The origins and spread of domestic horses from the Western Eurasian steppes |journal=Nature |language=en |volume=598 |issue=7882 |pages=634–640 |doi=10.1038/s41586-021-04018-9 |issn=1476-4687 |pmc=8550961 |pmid=34671162|bibcode=2021Natur.598..634L }}</ref>

By 3000 BCE, the horse was completely domesticated and by 2000 BCE there was a sharp increase in the number of horse bones found in human settlements in northwestern Europe, indicating the spread of domesticated horses throughout the continent.<ref>{{cite book |author=Evans, James Warren |url=https://books.google.com/books?id=QofYEVPeIBUC&pg=PA56 |title=Horse Breeding and Management |publisher=Elsevier Health Sciences |location=Amsterdam |year=1992 |isbn=0-444-88282-0 |oclc=243738023 |page=56 }}{{Dead link|date=April 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> The most recent, but most irrefutable evidence of domestication comes from sites where horse remains were interred with chariots in graves of the Indo-European [[Sintashta]] and [[Petrovka settlement|Petrovka]] cultures {{circa}} 2100 BCE.<ref name="Kuznetsov2006">{{cite journal | last = Kuznetsov | first = P. F. | year = 2006 | title = The emergence of Bronze Age chariots in eastern Europe | journal = [[Antiquity (journal)|Antiquity]] | volume = 80 | issue = 309 | pages = 638–645 | doi=10.1017/S0003598X00094096| s2cid = 162580424 }}</ref>

A 2021 genetic study suggested that most modern domestic horses descend from the lower [[Volga region|Volga-Don region]]. [[Ancient DNA|Ancient horse genomes]] indicate that these populations influenced <!--mostly stallions crossed on local mares-->almost all local populations as they expanded rapidly throughout [[Eurasia]], beginning about 4,200 years ago. It also shows that certain adaptations were strongly selected due to [[equestrianism|riding]], and that [[Horse culture|equestrian material culture]], including [[Sintashta culture|Sintashta]] spoke-wheeled [[chariot]]s spread with the horse itself.<ref>{{cite news |author-first1=Jonathan |author-last1=Lambert |title=Scientists found modern domestic horses' homeland in southwestern Russia |url=https://www.sciencenews.org/article/dna-genes-modern-domestic-horses-origin-russia |access-date=14 November 2021 |work=Science News |date=20 October 2021 |archive-date=14 November 2021 |archive-url=https://web.archive.org/web/20211114232955/https://www.sciencenews.org/article/dna-genes-modern-domestic-horses-origin-russia |url-status=live }}</ref><ref>{{cite journal |author=Pablo Librado |display-authors=et al. |title=The origins and spread of domestic horses from the Western Eurasian steppes |journal=Nature |date=October 2021 |volume=598 |issue=7882 |pages=634–640 |doi=10.1038/s41586-021-04018-9 |pmid=34671162 |pmc=8550961 |bibcode=2021Natur.598..634L |language=en |issn=1476-4687}}</ref>

Domestication is also studied by using the genetic material of present-day horses and comparing it with the genetic material present in the bones and teeth of horse remains found in archaeological and palaeological excavations. The variation in the genetic material shows that very few wild stallions contributed to the domestic horse,<ref name=Lau>{{cite journal|doi=10.1093/molbev/msn239|author1=Lau, A. N. |author2= Peng, L.|author3= Goto, H.|author4= Chemnick, L.|author5= Ryder, O. A. |author6= Makova, K. D. |year= 2009 |title= Horse Domestication and Conservation Genetics of Przewalski's Horse Inferred from Sex Chromosomal and Autosomal Sequences| journal= Molecular Biology and Evolution |volume=26 |issue=1 |pages= 199–208 |pmid=18931383 |doi-access= free}}</ref><ref name="Lindgren2004">{{cite journal | last = Lindgren | first = Gabriella |author2=Niclas Backström |author3=June Swinburne |author4=Linda Hellborg |author5=Annika Einarsson |author6=Kaj Sandberg |author7=Gus Cothran |author8=Carles Vilà |author9=Matthew Binns |author10=Hans Ellegren | year =2004 | title = Limited number of patrilines in horse domestication | journal = [[Nature Genetics]] | pmid = 15034578 | volume = 36 | issue = 4 | pages = 335–336 | doi = 10.1038/ng1326| doi-access =free}}</ref> while many mares were part of early domesticated herds.<ref name=Lira>{{cite journal | title=Ancient DNA reveals traces of Iberian Neolithic and Bronze Age lineages in modern Iberian horses | author=Lira, Jaime | journal=Molecular Ecology | volume=19 | issue=1 | pages=64–78 | year=2010 | pmid=19943892 | doi=10.1111/j.1365-294X.2009.04430.x | bibcode=2010MolEc..19...64L | s2cid=1376591 | display-authors=etal | url=http://eprints.ucm.es/10548/2/Mol_Ecol_2009_Lira_et_al_Ancient_Iberian_horses.pdf | access-date=2018-04-20 | archive-date=2017-08-10 | archive-url=https://web.archive.org/web/20170810142737/http://eprints.ucm.es/10548/2/Mol_Ecol_2009_Lira_et_al_Ancient_Iberian_horses.pdf | url-status=live }}</ref><ref name="Vila2001">{{cite journal | last1 = Vilà | first1 = C. | year = 2001 | title = Widespread origins of domestic horse lineages | journal = [[Science (journal)|Science]] | volume = 291 | issue = 5503 | pages = 474–477 | doi = 10.1126/science.291.5503.474 | pmid = 11161199 | display-authors = 1 | last2 = Leonard | first2 = JA | last3 = Gotherstrom | first3 = A | last4 = Marklund | first4 = S | last5 = Sandberg | first5 = K | last6 = Liden | first6 = K | last7 = Wayne | first7 = RK | last8 = Ellegren | first8 = H| bibcode = 2001Sci...291..474V}}</ref><ref name=Cai>{{cite journal | doi = 10.1016/j.jas.2008.11.006 | last1 = Cai | first1 = D. W. | last2 = Tang | first2 = Z. W. | last3 = Han | first3 = L. | last4 = Speller | first4 = C. F. | last5 = Yang | first5 = D. Y. Y. | last6 = Ma | first6 = X. L. | last7 = Cao | first7 = J. E. | last8 = Zhu | first8 = H. | last9 = Zhou | first9 = H. | year = 2009 | title = Ancient DNA provides new insights into the origin of the Chinese domestic horse | url = https://www.sfu.ca/~donyang/adnaweb/Cai%20DW%20JAS2009.pdf | access-date = 17 January 2011 | journal = Journal of Archaeological Science | volume = 36 | issue = 3 | pages = 835–842 | bibcode = 2009JArSc..36..835C | display-authors = etal | archive-date = 29 June 2011 | archive-url = https://web.archive.org/web/20110629014405/http://www.sfu.ca/~donyang/adnaweb/Cai%20DW%20JAS2009.pdf | url-status = live }}</ref> This is reflected in the difference in genetic variation between the DNA that is passed on along the paternal, or sire line ([[Y-chromosome]]) versus that passed on along the maternal, or dam line ([[mitochondrial DNA]]). There are very low levels of Y-chromosome variability,<ref name=Lau/><ref name="Lindgren2004" /> but a great deal of genetic variation in mitochondrial DNA.<ref name=Lira/><ref name="Vila2001"/><ref name=Cai/> There is also regional variation in mitochondrial DNA due to the inclusion of wild mares in domestic herds.<ref name=Lira/><ref name="Vila2001"/><ref name=Cai/><ref>{{cite encyclopedia |author=Olsen, Sandra L.|title=Early Horse Domestication: Weighing the Evidence| encyclopedia=Horses & Humans: The Evolution of Human-Equine Relationships |editor1=Olsen, Sandra L |editor2=Grant, Susan |editor3=Choyke, Alice M. |editor4=Bartosiewicz, Laszlo |publisher=Archaeopress |location=Oxford, UK |year=2006 |pages=81–113 |isbn=978-1-84171-990-0}}</ref> Another characteristic of domestication is an increase in coat color variation.<ref>{{cite journal |author=Epstein, H. |year=1955 |title=Domestication Features in Animals as Functions of Human Society |journal=Agricultural History Society |volume= 29|issue=4|pages= 137–146 |jstor=3740046}}</ref> In horses, this increased dramatically between 5000 and 3000 BCE.<ref name=coatColor>{{cite journal | doi = 10.1126/science.1172750 | last1 = Ludwig | first1 = A. | last2 = Pruvost | first2 = M. | last3 = Reissmann | first3 = M. | last4 = Benecke | first4 = N. | last5 = Brockmann | first5 = G.A. | last6 = Castanos | first6 = P. | last7 = Cieslak | first7 = M. | last8 = Lippold | first8 = S. | last9 = Llorente | first9 = L.| year = 2009 | title = Coat Color Variation at the Beginning of Horse Domestication |journal = Science | volume = 324 | issue = 5926| pages = 485 | pmid=19390039|display-authors=etal | pmc=5102060| bibcode = 2009Sci...324..485L}}</ref>

Before the availability of DNA techniques to resolve the questions related to the domestication of the horse, various hypotheses were proposed. One classification was based on body types and conformation, suggesting the presence of four basic prototypes that had adapted to their environment prior to domestication.<ref name="Bennett7">{{cite book |author= Bennett, Deb |title= Conquerors: The Roots of New World Horsemanship |edition= First |publisher= Amigo Publications, Inc. |location= Solvang, CA |year= 1998 |isbn=0-9658533-0-6 |oclc= 39709067|page=7}}</ref> Another hypothesis held that the four prototypes originated from a single wild species and that all different body types were entirely a result of [[selective breeding]] after domestication.<ref>{{cite book |author=Edwards, Gladys Brown |title=The Arabian: War Horse to Show Horse |publisher=Rich Publishing |year=1973 |edition=Revised Collectors |pages= 1, 3}}</ref> However, the lack of a detectable substructure <!--huh? what's that? Can we explain in everyday language?--> in the horse has resulted in a rejection of both hypotheses.<!--I will add the ref for it once I find the book back--><!--OK-->

===Feral populations===
{{Main|Feral horse}}
[[Feral]] horses are born and live in the wild, but are descended from domesticated animals.<ref name=Olsen46/> Many populations of [[feral horse]]s exist throughout the world.<ref>[[#Edwards|Edwards]], p. 291</ref><ref>{{cite book|author= Anthony, David W. |chapter= Bridling Horse Power: The Domestication of the Horse |title= Horses Through Time |edition= First |publisher= Roberts Rinehart Publishers| location= Boulder, CO |year= 1996 |isbn= 1-57098-060-8 |oclc= 36179575 |pages= [https://archive.org/details/horsesthroughtim00olse/page/66 66–67] |chapter-url= https://archive.org/details/horsesthroughtim00olse/page/66}}</ref> Studies of feral herds have provided useful insights into the behavior of prehistoric horses,<ref>{{cite web |url=http://www.carnegiemnh.org/anthro/olsen_horse.html | author=Olsen, Sandra L. |title= Horses in Prehistory |website=Anthropology Research | publisher=Carnegie Museum of Natural History |access-date=2008-08-16 |archive-url = https://web.archive.org/web/20080525183100/http://www.carnegiemnh.org/anthro/olsen_horse.html |archive-date = May 25, 2008}}</ref> as well as greater understanding of the instincts and behaviors that drive horses that live in domesticated conditions.<ref>{{cite web|url=http://www.thehorse.com/ViewArticle.aspx?ID=15037 |title=Mares' Social Bonds Might Enhance Reproductive Success |date=October 7, 2009 |access-date=2009-10-21 |website=The Horse |url-access=registration | author=Lesté-Lasserre, Christa |archive-url=https://web.archive.org/web/20120415005227/http://www.thehorse.com/ViewArticle.aspx?ID=15037 |archive-date=April 15, 2012 |url-status=dead}}</ref>

There are also [[semi-feral]] horses in many parts of the world, such as [[Dartmoor]] and the [[New Forest]] in the UK, where the animals are all privately owned but live for significant amounts of time in "wild" conditions on undeveloped, often public, lands. Owners of such animals often pay a fee for grazing rights.<ref>{{cite web |url=http://www.dartmoorcommonerscouncil.org.uk/menu_page.php?id=53 |publisher=Dartmoor Commoners' Council |title=Animals on the Moor |access-date=2012-03-29 |archive-date=2017-10-10 |archive-url=https://web.archive.org/web/20171010200000/http://www.dartmoorcommonerscouncil.org.uk/menu_page.php?id=53 |url-status=live }}</ref><ref name=Fear75>{{cite book |author=Fear, Sally |title=New Forest Drift: A Photographic Portrait of Life in the National Park |publisher= Perspective Photo Press |year= 2006 |isbn=978-0-9553253-0-4 |page= 75}}</ref><!-- could also include Carmarque horse of France and a lot of the big QH ranches in Texas-->

===Breeds===
{{Main|Horse breed||List of horse breeds|Horse breeding}}

The concept of [[purebred]] bloodstock and a controlled, written [[breed registry]] has come to be particularly significant and important in modern times. Sometimes purebred horses are incorrectly or inaccurately called "thoroughbreds". [[Thoroughbred]] is a specific breed of horse, while a "purebred" is a horse (or any other animal) with a defined [[Pedigree chart|pedigree]] recognized by a breed registry.<ref name=Ensminger424>[[#Ensminger|Ensminger]], p. 424</ref> Horse breeds are groups of horses with distinctive characteristics that are transmitted consistently to their offspring, such as [[equine conformation|conformation]], color, performance ability, or disposition. These inherited traits result from a combination of natural crosses and [[artificial selection]] methods. Horses have been [[Selective breeding|selectively bred]] since their [[domestication of the horse|domestication]]. An early example of people who practiced selective [[horse breeding]] were the [[Bedouin]], who had a reputation for careful practices, keeping extensive pedigrees of their [[Arabian horse]]s and placing great value upon pure bloodlines.<ref>{{cite book |author=Edwards, Gladys Brown |title=The Arabian: War Horse to Show Horse |publisher=Rich Publishing |year=1973 |edition=Revised Collectors |pages=22–23}}</ref> These pedigrees were originally transmitted via an [[oral tradition]].<ref>{{cite web|url=http://www.waho.org/History.html |title=Is Purity the Issue? |access-date=2008-04-29 |website=WAHO Publication Number 21 January 1998 |publisher=World Arabian Horse Organization |url-status=dead |archive-url=https://web.archive.org/web/20080705105054/http://www.waho.org/Purityissue.html |archive-date=5 July 2008 }}</ref>

Breeds developed due to a need for "form to function", the necessity to develop certain characteristics in order to perform a particular type of work.<ref name=Sponenberg155>[[#Sponenberg|Sponenberg]], p. 155</ref> Thus, a powerful but refined breed such as the Andalusian developed as riding horses with an aptitude for [[dressage]].<ref name=Sponenberg155/> Heavy draft horses were developed out of a need to perform demanding [[farm]] work and pull heavy wagons.<ref>[[#Sponenberg|Sponenberg]], pp. 156–157</ref> Other horse breeds had been developed specifically for light agricultural work, carriage and road work, various sport disciplines, or simply as pets.<ref name=Spon162>[[#Sponenberg|Sponenberg]], p. 162</ref> Some breeds developed through centuries of crossing other breeds, while others descended from a single [[foundation stock|foundation sire]], or other limited or restricted foundation bloodstock. One of the earliest formal registries was [[General Stud Book]] for Thoroughbreds, which began in 1791 and traced back to the [[foundation bloodstock]] for the breed.<ref>{{cite web|url=http://www.britishhorseracing.com/goracing/racing/racehorses/history.asp |title=History of Thoroughbreds |access-date=2008-04-03 |website=Britishhorseracing.com |publisher=British Horseracing Authority |url-status=dead |archive-url=https://web.archive.org/web/20140201154621/http://www.britishhorseracing.com/goracing/racing/racehorses/history.asp |archive-date=2014-02-01 }}</ref> There are more than 300&nbsp;horse breeds in the world today.<ref>{{cite book |author1=Hedge, Juliet |author2=Don M. Wagoner |title= Horse Conformation: Structure, Soundness and Performance |publisher= Globe Pequot |location=Guilford, CT |year= 2004|isbn= 1-59228-487-6 |oclc= 56012597|pages=307–308}}</ref>

==Interaction with humans==
[[File:Murron-Ryhti pulling.png|thumb|[[Finnhorse]] pulling a heavy wagon.]]
Worldwide, horses play a role within human cultures and have done so for millennia. Horses are used for leisure activities, sports, and working purposes. The [[Food and Agriculture Organization]] (FAO) estimates that in 2008, there were almost 59,000,000 horses in the world, with around 33,500,000 in the Americas, 13,800,000 in Asia and 6,300,000 in Europe and smaller portions in Africa and Oceania. There are estimated to be 9,500,000 horses in the United States alone.<ref>{{cite web |url=http://faostat.fao.org/site/573/DesktopDefault.aspx?PageID=573#ancor |publisher=Food and Agriculture Organization |date=December 16, 2009 |access-date=2010-02-05 |title=FAO Stat&nbsp;– Live Animals |archive-date=2013-01-19 |archive-url=https://web.archive.org/web/20130119095737/http://faostat.fao.org/site/573/DesktopDefault.aspx?PageID=573#ancor |url-status=live }}</ref> The [[American Horse Council]] estimates that horse-related activities have a direct impact on the economy of the United States of over $39 billion, and when indirect spending is considered, the impact is over $102 billion.<ref>{{cite press release |url= http://www.cthorsecouncil.org/AHC2005JuneEconStudy.pdf|title= Most Comprehensive Horse Study Ever Reveals A Nearly $40 Billion Impact On The U.S. Economy |access-date=2005-06-20 |publisher= American Horse Council |archive-url = https://web.archive.org/web/20060625083812/http://www.cthorsecouncil.org/AHC2005JuneEconStudy.pdf |archive-date = June 25, 2006}}</ref> In a 2004 "poll" conducted by [[Animal Planet]], more than 50,000 viewers from 73 countries voted for the horse as the world's 4th favorite animal.<ref name=IOL>{{cite web|url= http://www.iol.co.za/news/back-page/tiger-tops-dog-as-world-s-favourite-animal-1.228797|title= Tiger tops dog as world's favourite animal|access-date= 2011-06-01|website= Independent Online|publisher= Independent|archive-date= 2012-10-28|archive-url= https://web.archive.org/web/20121028071911/http://www.iol.co.za/news/back-page/tiger-tops-dog-as-world-s-favourite-animal-1.228797|url-status= live}}</ref>

Communication between human and horse is paramount in any equestrian activity;<ref name="Olsen"/> to aid this process horses are usually ridden with a [[saddle]] on their backs to assist the rider with balance and positioning, and a [[bridle]] or related headgear to assist the rider in maintaining control.<ref>{{cite book |author=Edwards, Elwyn Hartley |title=Horses |edition=Second American |publisher=Dorling Kindersley |location= New York |year=2002 |isbn=0-7894-8982-1 |oclc=50798049|pages= 32–34}}</ref> Sometimes horses are ridden without a saddle,<ref>{{cite book|author=Self, Margaret Cabell|title=Riding Simplified|url=https://books.google.com/books?id=iUTm7aD1Mf8C&pg=PA55|publisher=Kessinger Publishing|year=2005|isbn=1-4191-0087-4|page=55}}{{Dead link|date=March 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> and occasionally, horses are trained to perform without a bridle or other headgear.<ref>{{cite encyclopedia |author=Thorson, Juli S. |title=Rugged Lark |editor= Martindale, Cathy and Kathy Swan |encyclopedia= Legends 7: Outstanding Quarter Horse Stallions and Mares |publisher=Western Horseman |location= Colorado Springs, CO |year=2006 |isbn=978-0-911647-79-2 |page=218}}</ref> Many horses are also [[Driving (horse)|driven]], which requires a [[horse harness|harness]], bridle, and some type of [[horse-drawn vehicle|vehicle]].<ref>{{cite book |author= Mettler, John J Jr.|title= Horse Sense: A Complete Guide to Horse Selection and Care |url= https://archive.org/details/horsesensecomple00mett|url-access= registration |publisher= Storey Communications, Inc. |location= Pownal, VT |year= 1989 |isbn=0-88266-549-9 |oclc= 19324181 |pages=[https://archive.org/details/horsesensecomple00mett/page/47 47–54]}}</ref>

===Sport===
<!-- There is a whole article about Equestrianism for all details about every possible sport. This article should only give the bare summary. So, please do not add elaborate sections of your own favorite horse sport here. -->
[[File:Beijing2008 HOKETSU Hiroshi.JPG|thumb|upright 1.2|A horse and rider in [[dressage]] competition at the [[Equestrian at the Summer Olympics|Olympics]]|alt=A chestnut (reddish-brown) horse being ridden by a rider in a black coat and top hat. They are stopped in a riding arena with the rider tipping his hat.]]
{{Main|Equestrianism|Horse racing|Horse training|Horse tack}}
Historically, equestrians honed their skills through games and races. Equestrian sports provided entertainment for crowds and honed the excellent horsemanship that was needed in battle. Many sports, such as [[dressage]], [[eventing]], and [[show jumping]], have origins in [[horses in warfare|military training]], which were focused on control and balance of both horse and rider. Other sports, such as [[rodeo]], developed from practical skills such as those needed on working [[ranch]]es and [[Station (Australian agriculture)|stations]]. Sport hunting from horseback evolved from earlier practical hunting techniques.<ref name="Olsen">{{cite book|author= Olsen, Sandra L. |chapter= In the Winner's Circle: The History of Equestrian Sports |title= Horses Through Time |edition= First |publisher= Roberts Rinehart Publishers |location= Boulder, CO |year= 1996 |isbn= 1-57098-060-8 |oclc= 36179575 |pages= [https://archive.org/details/horsesthroughtim00olse/page/105 105, 111–113, 121] |chapter-url= https://archive.org/details/horsesthroughtim00olse/page/105}}</ref> [[Horse racing]] of all types evolved from impromptu competitions between riders or drivers. All forms of competition, requiring demanding and specialized skills from both horse and rider, resulted in the systematic development of specialized breeds and equipment for each sport. The popularity of equestrian sports through the centuries has resulted in the preservation of skills that would otherwise have disappeared after horses stopped being used in combat.<ref name="Olsen"/>

Horses are trained to be ridden or driven in a variety of sporting competitions. Examples include [[show jumping]], [[dressage]], three-day [[eventing]], [[combined driving|competitive driving]], [[endurance riding]], [[Gymkhana (equestrian)|gymkhana]], [[rodeo]]s, and [[fox hunting]].<ref>[[#Edwards|Edwards]], pp. 346–356, 366–371</ref> [[Horse show]]s, which have their origins in medieval European fairs, are held around the world. They host a huge range of classes, covering all of the mounted and harness disciplines, as well as [[halter (horse show)|"In-hand"]] classes where the horses are led, rather than ridden, to be evaluated on their conformation. The method of judging varies with the discipline, but winning usually depends on style and ability of both horse and rider.<ref>[[#Edwards|Edwards]], pp. 376–377</ref>
Sports such as [[polo]] do not judge the horse itself, but rather use the horse as a partner for human competitors as a necessary part of the game. Although the horse requires specialized training to participate, the details of its performance are not judged, only the result of the rider's actions—be it getting a ball through a goal or some other task.<ref name=Edwards360>[[#Edwards|Edwards]], p. 360</ref> Examples of these sports of partnership between human and horse include [[jousting]], in which the main goal is for one rider to unseat the other,<ref>{{cite book|author1=Collins, Tony|author2=Martin, John|author3=Vamplew, Wray|title=Encyclopedia of Traditional British Rural Sports|url=https://books.google.com/books?id=NWu6sLJn7-kC&pg=PA174|publisher=Routledge|year=2005|location=London|isbn=0-415-35224-X|oclc=57005595|pages=173–174|access-date=2020-09-28|archive-date=2023-03-20|archive-url=https://web.archive.org/web/20230320223813/https://books.google.com/books?id=NWu6sLJn7-kC&pg=PA174|url-status=live}}</ref> and [[buzkashi]], a team game played throughout [[Central Asia]], the aim being to capture a goat carcass while on horseback.<ref name=Edwards360/>

[[Horse racing]] is an equestrian sport and major international industry, watched in almost every nation of the world. There are three types: "flat" racing; [[Steeplechase (horse racing)|steeplechasing]], i.e. racing over jumps; and [[harness racing]], where horses trot or pace while pulling a driver in a small, light cart known as a [[sulky]].<ref>[[#Edwards|Edwards]], pp. 332–337</ref> A major part of horse racing's economic importance lies in the [[Gambling#Parimutuel betting|gambling]] associated with it.<ref>{{cite book |author=Campbell, B.N. |url=https://books.google.com/books?id=-p7ZF9KW8-MC |title=National Gambling Impact Study Commission Final Report (1999) |publisher=DIANE Publishing |location=Darby, PA |year=2001 |isbn=0-7567-0701-3 |page=111 |access-date=2015-11-15 |archive-date=2023-03-20 |archive-url=https://web.archive.org/web/20230320223813/https://books.google.com/books?id=-p7ZF9KW8-MC |url-status=live }}</ref>

===Work===
 {{multiple image
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 | image1 = Tanga (carriage) at Darbhanga Bihar.jpg
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 | alt1 = Tired-looking bay horse hitched to a rustic cart
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| image2 = Policja konna Poznań.jpg
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 | alt2 = A mounted man in a blue uniform on a dark brown horse
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There are certain jobs that horses do very well, and no technology has yet developed to fully replace them. For example, [[mounted police]] horses are still effective for certain types of patrol duties and crowd control.<ref>{{cite web|url=http://www.nps.gov/uspp/fhorsepage.htm |title=Horse Mounted Unit |access-date=2008-04-07 |website=United States Park Police |publisher=National Park Service |url-status=dead |archive-url=https://web.archive.org/web/20080218130631/http://www.nps.gov/uspp/fhorsepage.htm |archive-date=February 18, 2008}}</ref> Cattle [[ranch]]es still require riders on horseback to round up cattle that are scattered across remote, rugged terrain.<ref>[[#Edwards|Edwards]], pp. 226–227</ref> [[Search and rescue]] organizations in some countries depend upon [[mounted search and rescue|mounted]] teams to locate people, particularly hikers and children, and to provide disaster relief assistance.<ref>{{cite web|url= http://www.sbcsheriff.org/msru_job.html|title= Volunteer Mounted Search and Rescue Unit |access-date= 2008-07-08 |website= Employment |publisher= San Benito County Sheriff's Office |archive-url= https://web.archive.org/web/20080509194223/http://www.sbcsheriff.org/msru_job.html |archive-date= 2008-05-09|url-status= dead}}</ref> Horses can also be used in areas where it is necessary to avoid vehicular disruption to delicate soil, such as nature reserves. They may also be the only form of transport allowed in [[wilderness area]]s. Horses are quieter than motorized vehicles. [[Law enforcement officer]]s such as [[park ranger]]s or [[game warden]]s may use horses for patrols, and horses or mules may also be used for clearing trails or other work in areas of rough terrain where vehicles are less effective.<ref>{{cite book |chapter-url=http://www.fs.fed.us/r9/publications/success_story_updates/2003-05.pdf |title=Success Stories |access-date=2008-04-20 |author=US Forest Service |date=May 2003 |chapter=Mules Key in Accomplishing Trail Work |publisher=US Department of Agriculture |page=4 |archive-date=2008-05-27 |archive-url=https://web.archive.org/web/20080527220145/http://www.fs.fed.us/r9/publications/success_story_updates/2003-05.pdf |url-status=live }}</ref>

Although machinery has replaced horses in many parts of the world, an estimated 100&nbsp;million horses, donkeys and mules are still used for agriculture and transportation in less developed areas. This number includes around 27&nbsp;million [[working animal]]s in Africa alone.<ref>{{cite journal |url=http://www.thehorse.com/ViewArticle.aspx?ID=7001 |title=At Work in Morocco |url-access=registration |author=Brown, Kimberly S. |journal=The Horse |date=June 1, 2006 |access-date=2009-10-21 |archive-date=2007-12-22 |archive-url=https://web.archive.org/web/20071222073228/http://www.thehorse.com/ViewArticle.aspx?ID=7001 |url-status=live }}</ref> Some land management practices such as cultivating and logging can be efficiently performed with horses. In agriculture, less fossil fuel is used and increased environmental conservation occurs over time with the use of [[working animal|draft animals]] such as horses.<ref>{{cite book|author=Gifford, Angela |chapter=Working Draught Horses as Singles and Pairs |title=The Working Horse Manual |publisher=Farming Press |location=Tonbridge, UK |isbn=0-85236-401-6|orig-year=1998|year=2000|oclc=40464050|page=85}}</ref><ref>{{cite book|author=Miller, Lynn R. |title=Work Horse Handbook |publisher=Small Farmer's Journal Inc. |location=Sisters, OR |orig-year=1981 |year=2000 |edition=First Edition, Fifteenth Impression |isbn=0-9607268-0-2 |oclc=234277549 |page=13}}</ref> Logging with horses can result in reduced damage to soil structure and less damage to trees due to more selective logging.<ref>{{cite book|author=Gifford, Angela |chapter=Working Horses in Forestry |title=The Working Horse Manual |publisher=Farming Press |location= Tonbridge, UK |isbn=0-85236-401-6|orig-year=1998|year=2000|oclc=40464050|page=145}}</ref>

===Warfare===
{{Main|Horses in warfare}}
[[File:Bundesarchiv Bild 146-1970-073-17, Türkische Kavallerie südlich von Jerusalem.jpg|thumb|[[Ottoman Empire|Ottoman]] cavalry, 1917|alt=Black-and-white photo of mounted soldiers with middle eastern headwraps, carrying rifles, walking down a road away from the camera]]
Horses have been used in warfare for most of recorded history. The first archaeological evidence of horses used in warfare dates to between 4000 and 3000 BCE,<ref name="Science Show">{{cite web |url=http://www.abc.net.au/radionational/programs/scienceshow/the-horse-in-history/3556066 |title=The Horse in History |access-date=2012-01-04 |author1=Newby, Jonica |author2=Diamond, Jared |author3=Anthony, David |website=The Science Show |date=1999-11-13 |publisher=Radio National |archive-date=2013-01-19 |archive-url=https://web.archive.org/web/20130119105447/http://www.abc.net.au/radionational/programs/scienceshow/the-horse-in-history/3556066 |url-status=live }}</ref> and the use of horses in warfare was widespread by the end of the [[Bronze Age]].<ref name="Hartwick">{{cite web|url=http://users.hartwick.edu/anthonyd/harnessing%20horsepower.html |title=The Earliest Horseback Riding and its Relation to Chariotry and Warfare|author1=Anthony, David W.|author2=Dorcas R. Brown |website=Harnessing Horsepower |publisher=Institute for Ancient Equestrian Studies|access-date=2007-10-09|archive-url=https://web.archive.org/web/20171010200000/http://users.hartwick.edu/anthonyd/harnessing%20horsepower.html |archive-date=2017-10-10|url-status=dead}}</ref><ref name=Whitaker30>[[#Whitaker|Whitaker]], pp. 30–31</ref> Although mechanization has largely replaced the horse as a weapon of war, horses are still seen today in limited military uses, mostly for ceremonial purposes, or for reconnaissance and transport activities in areas of rough terrain where motorized vehicles are ineffective. Horses have been used in the 21st century by the [[Janjaweed]] militias in the [[War in Darfur]].<ref>{{cite news |url= https://www.nytimes.com/2004/05/04/international/africa/04DARF.html |title= In Sudan, Militiamen on Horses Uproot a Million |access-date= 2011-01-04 |author= Lacey, Marc |work= The New York Times |date= 2004-05-04 |archive-date= 2009-04-23 |archive-url= https://web.archive.org/web/20090423111741/http://www.nytimes.com/2004/05/04/international/africa/04DARF.html |url-status= live }}</ref>

===Entertainment and culture===
[[File:Hayagreeva.jpg|thumb|upright|The horse-headed deity in [[Hinduism]], [[Hayagriva]]]]
{{See also|Horse symbolism|Horses in art|Horse worship}}
Modern horses are often used to reenact many of their historical work purposes. Horses are used, complete with equipment that is authentic or a meticulously recreated replica, in various live action [[historical reenactment]]s of specific periods of history, especially recreations of famous battles.<ref>{{cite web |url= http://www.blackhorsetroop.org/activities/ |title= Unit Activities |access-date= 2008-04-29 |author= Stoddard, Samuel |website= Co H, 4th Virginia Cavalry |publisher= Washington Webworks, LLC |archive-date= 2008-01-18 |archive-url= https://web.archive.org/web/20080118205712/http://blackhorsetroop.org/activities/ |url-status= live }}</ref> Horses are also used to preserve cultural traditions and for ceremonial purposes. Countries such as the United Kingdom still use horse-drawn carriages to convey royalty and other VIPs to and from certain culturally significant events.<ref>{{cite web |url= http://www.royal.gov.uk/TheRoyalHousehold/Transport/Transport.aspx |title= Transport |access-date= 2009-08-30 |publisher= British Monarchy |archive-date= 2009-02-16 |archive-url= https://web.archive.org/web/20090216150048/http://www.royal.gov.uk/TheRoyalHousehold/Transport/Transport.aspx |url-status= live }}</ref> Public exhibitions are another example, such as the [[Budweiser Clydesdales]], seen in parades and other public settings, a team of [[draft horse]]s that pull a beer wagon similar to that used before the invention of the modern motorized truck.<ref>{{cite news |title=Anheuser-Busch gives face time to Budweiser Clydesdales |work=St. Louis Post-Dispatch |author=McWilliams, Jeremiah |access-date=2010-09-18 |date=December 3, 2008 |url=http://www.stltoday.com/business/columns/lager-heads/article_98704685-a144-52b1-aba7-7b580e8f8c08.html |archive-date=2012-05-14 |archive-url=https://web.archive.org/web/20120514075122/http://www.stltoday.com/business/columns/lager-heads/article_98704685-a144-52b1-aba7-7b580e8f8c08.html |url-status=live }}</ref>

Horses are frequently used in television, films and literature. They are sometimes featured as a major character in films about particular animals, but also used as visual elements that assure the accuracy of historical stories.<ref>{{cite journal|url=http://www.thehorse.com/ViewArticle.aspx?ID=6630|title=Hollywood Horses|author=Sellnow, Les|date=March 1, 2006|access-date=2009-10-21|url-access=registration|journal=The Horse|archive-date=2011-09-05|archive-url=https://web.archive.org/web/20110905044227/http://www.thehorse.com/ViewArticle.aspx?ID=6630|url-status=live}}</ref> Both live horses and [[Cultural icon|iconic]] images of horses are used in [[advertising]] to promote a variety of products.<ref>{{cite web|url=http://www.hippomaxx-muenster.de/english/sonderausstellung.php?navid=7|title=Trademark Horse&nbsp;– Horses as advertising mediums |publisher=Westfälische Pferdemuseum (Westphalian Horse Museum) |access-date=2008-08-16 |archive-url= https://web.archive.org/web/20081011201036/http://www.hippomaxx-muenster.de/english/sonderausstellung.php?navid=7|archive-date=2008-10-11 |url-status=dead}}</ref> The horse frequently appears in coats of arms in [[heraldry]], in a variety of poses and equipment.<ref>{{cite book|author=Fox-Davies, Arthur Charles|title=A Complete Guide to Heraldry|url=https://books.google.com/books?id=xSeEWjQCTIAC&pg=PA202|publisher=Skyhorse Publishing Inc|year=2007|isbn=978-1-60239-001-0|page=201|access-date=2020-09-28|archive-date=2023-03-20|archive-url=https://web.archive.org/web/20230320223813/https://books.google.com/books?id=xSeEWjQCTIAC&pg=PA202|url-status=live}}</ref> The [[mythology|mythologies]] of many cultures, including [[Greco-Roman mythology|Greco-Roman]], [[Hindu mythology|Hindu]], [[Islamic mythology|Islamic]], and [[Horses in Germanic paganism|Germanic]], include references to both normal horses and those with wings or additional limbs, and multiple myths also call upon the horse to draw the chariots of the Moon and Sun.<ref>{{cite book|author=Tozer, Basil |title=The Horse in History |url=https://archive.org/details/TheHorseInHistory |publisher=Methuen |year=1908 |location=London |oclc=2484673 |pages=[https://archive.org/details/TheHorseInHistory/page/n134 94], 98–100}}</ref> The horse also appears in the 12-year cycle of animals in the [[Chinese astrology|Chinese zodiac]] related to the [[Chinese calendar]].<ref>{{cite web |url= http://www.c-c-c.org/chineseculture/zodiac/Horse.html|archive-url= https://web.archive.org/web/20110716104433/http://www.c-c-c.org/chineseculture/zodiac/Horse.html|archive-date= 2011-07-16|title= Year of the Horse |access-date=2007-07-22|publisher= Chinese Culture Center of San Francisco}}</ref>

Horses serve as the inspiration for many modern automobile names and logos, including the [[Ford Pinto]], [[Ford Bronco]], [[Ford Mustang]], [[Hyundai Equus]], [[Hyundai Pony]], [[Mitsubishi Starion]], [[Subaru BRAT|Subaru Brumby]], [[Mitsubishi Colt]]/[[Dodge Colt]], [[Steyr-Puch Pinzgauer|Pinzgauer]], [[Steyr-Puch Haflinger]], [[Pegaso]], [[Porsche]], [[Rolls-Royce Camargue]], [[Ferrari]], [[Carlsson (car company)|Carlsson]], [[Kamaz]], [[Corre La Licorne]], [[Iran Khodro]], [[Eicher Motors|Eicher]], and [[Baojun]].<ref>{{cite web |url=https://www.autoguide.com/auto-news/2016/02/top-10-horse-themed-cars.html |title=Giddy Up: Top 10 Horse-Themed Cars |work=Autoguide.com |last=Cole |first=Craig |date=8 November 2021 |access-date=7 July 2022 |archive-date=25 May 2022 |archive-url=https://web.archive.org/web/20220525011426/https://www.autoguide.com/auto-news/2016/02/top-10-horse-themed-cars.html |url-status=live }}</ref><ref>{{cite web | url=https://www.globalcarsbrands.com/cars-with-horse-logos/ | title=Cars with Horse Logos: How Many of Them do You Know? | date=9 January 2022 | access-date=18 June 2022 | archive-date=28 May 2022 | archive-url=https://web.archive.org/web/20220528160402/https://www.globalcarsbrands.com/cars-with-horse-logos/ | url-status=live }}</ref><ref>{{cite web | url=https://journal.classiccars.com/2021/05/08/top-11-cars-named-after-horses-which-is-your-favorite/ | title=Top 11 cars named after horses, which is your favorite? | date=8 May 2021 | access-date=18 June 2022 | archive-date=16 August 2022 | archive-url=https://web.archive.org/web/20220816110754/https://journal.classiccars.com/2021/05/08/top-11-cars-named-after-horses-which-is-your-favorite/ | url-status=live }}</ref> Indian [[TVS Motor Company]] also uses a horse on their motorcycles & scooters.

===Therapeutic use===
{{See also|Equine-assisted therapy|Therapeutic horseback riding}}
People of all ages with physical and mental disabilities obtain beneficial results from an association with horses. Therapeutic riding is used to mentally and physically stimulate disabled persons and help them improve their lives through improved balance and coordination, increased self-confidence, and a greater feeling of freedom and independence.<ref>{{cite book |author1=Bush, Karen |author2=Julian Marczak |title=The Principles of Teaching Riding: The Official Manual of the Association of British Riding Schools |publisher=David & Charles |year=2005 |isbn=0-7153-1902-7 |url=https://books.google.com/books?id=uCQYEduHy8cC&pg=PA58 |oclc=224946044 |page=58 }}{{Dead link|date=April 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> The benefits of equestrian activity for people with disabilities has also been recognized with the addition of equestrian events to the [[Paralympic Games]] and recognition of [[para-equestrian]] events by the [[International Federation for Equestrian Sports]] (FEI).<ref>{{cite web|url=http://www.fei.org/disciplines/dressage/about-para-equestrian-dressage |title=About Para Equestrian Dressage |access-date=2010-03-07 |publisher=Federation Equestre Internationale |url-status=dead |archive-url= https://web.archive.org/web/20130508135709/http://www.fei.org/disciplines/dressage/about-para-equestrian-dressage |archive-date=2013-05-08 }}</ref> Hippotherapy and therapeutic horseback riding are names for different physical, occupational, and speech therapy treatment strategies that use equine movement. In hippotherapy, a therapist uses the horse's movement to improve their patient's cognitive, coordination, balance, and fine motor skills, whereas therapeutic horseback riding uses specific riding skills.<ref>{{cite web |url= http://www.narha.org/PDFFiles/FAQ_Hippotherapy.pdf|title= Frequently Asked Questions About Hippotherapy |access-date=2008-07-08 |website= FAQ&nbsp;– AHA, April 2005|publisher= American Hippotherapy Association |archive-url = https://web.archive.org/web/20070919090815/http://www.narha.org/PDFFiles/FAQ_Hippotherapy.pdf |archive-date = September 19, 2007}}</ref>

Horses also provide psychological benefits to people whether they actually ride or not. "Equine-assisted" or "equine-facilitated" therapy is a form of experiential [[psychotherapy]] that uses horses as companion animals to assist people with mental illness, including anxiety disorders, psychotic disorders, mood disorders, behavioral difficulties, and those who are going through major life changes.<ref>{{cite web |url=http://www.narha.org/SecEFMHA/FactSheet.asp|title=Equine Facilitated Psychotherapy (EFP) Fact Sheet |access-date=2008-07-08 |publisher= Equine Facilitated Mental Health Association |archive-url = https://web.archive.org/web/20080430025532/http://www.narha.org/SecEFMHA/FactSheet.asp |archive-date = April 30, 2008}}</ref> There are also experimental programs using horses in [[prison]] settings. Exposure to horses appears to improve the behavior of inmates and help reduce [[recidivism]] when they leave.<ref>{{cite news |author= Wise, Mike |date=2003-08-10|title= Partners, Horse and Man, in Prison Pasture |work= New York Times |url= https://query.nytimes.com/gst/fullpage.html?res=9404E6D91331F933A2575BC0A9659C8B63 |access-date=2008-07-08}}</ref>

===Products===
Horses are raw material for many products made by humans throughout history, including byproducts from the [[horse slaughter|slaughter]] of horses as well as materials collected from living horses.

Products collected from living horses include mare's milk, used by people with large horse herds, such as the [[Mongols]], who let it ferment to produce [[kumis]].<ref name=NewYorker>{{cite magazine |url= http://www.newyorker.com/archive/2005/04/25/050425fa_fact4 |title= Invaders: Destroying Baghdad |access-date= 2008-04-03 |author= Frazier, Ian |magazine= The New Yorker |date= 2005-04-18 |archive-date= 2017-10-10 |archive-url= https://web.archive.org/web/20171010200000/http://www.newyorker.com/archive/2005/04/25/050425fa_fact4 |url-status= live }}</ref> Horse blood was once used as food by the Mongols and other [[nomad]]ic tribes, who found it a convenient source of nutrition when traveling. Drinking their own horses' blood allowed the Mongols to ride for extended periods of time without stopping to eat.<ref name=NewYorker/> The drug [[Premarin]] is a mixture of [[estrogen]]s extracted from the urine of pregnant mares ('''pre'''gnant '''mar'''es' ur'''in'''e), and was previously a widely used drug for [[hormone replacement therapy]].<ref>{{cite web|url= http://www.humanesociety.org/news/news/2009/08/a_good_life_for_horses_at_duchess_sanctuary.html|title= A Good Life for Horses at the Duchess Sanctuary|access-date= 2011-06-01|date= August 19, 2001|author= Ballard, Pepper|publisher= The Humane Society of the United States|archive-date= 2013-01-28|archive-url= https://web.archive.org/web/20130128074914/http://www.humanesociety.org/news/news/2009/08/a_good_life_for_horses_at_duchess_sanctuary.html|url-status= dead}}</ref> The tail hair of horses can be used for making [[bow (music)|bows]] for [[string instrument]]s such as the [[violin]], [[viola]], [[cello]], and [[double bass]].<ref>{{cite book |title=Descriptionary: A Thematic Dictionary |author=McCutcheon, Marc |publisher=Checkmark Books (Facts On File imprint) |location=New York |edition=Second |isbn=0-8160-4105-9 |page=[https://archive.org/details/descriptionary00mccu_0/page/285 285] |year=2000 |url=https://archive.org/details/descriptionary00mccu_0/page/285}}</ref>

[[Horse meat]] has been used as food for humans and [[carnivore|carnivorous animals]] throughout the ages. Approximately 5 million horses are slaughtered each year for meat worldwide.<ref>{{Cite web|url=http://www.fao.org/faostat/en/#data/QL|title=FAOSTAT|website=Food and Agriculture Organization of the United Nations|access-date=2019-10-25|archive-date=2019-05-24|archive-url=https://web.archive.org/web/20190524180621/http://www.fao.org/faostat/en/#data/QL|url-status=live}}</ref> It is eaten in many parts of the world, though consumption is [[taboo]] in some cultures,<ref name=USDA>{{cite web|url= http://www.igha.org/USDA.html|title= U.S.D.A. Promotes Horse & Goat Meat |access-date= 2008-04-03 |website= I.G.H.A./HorseAid's U.S.D.A. Report |publisher= U.S. Department of Agriculture |archive-url= https://web.archive.org/web/20171010200000/http://www.igha.org/USDA.html |archive-date= 2017-10-10|url-status= dead}}</ref> and a subject of political controversy in others.<ref>{{cite news |url= http://www.sfgate.com/cgi-bin/article.cgi?file=%2Fc%2Fa%2F2006%2F09%2F08%2FMNGI9L1RMK1.DTL |title= House votes to outlaw slaughter of horses for human consumption |access-date= 2008-04-03 |author= Coile, Zachary |work= SF Gate |publisher= San Francisco Chronicle |date= 2006-09-08 |archive-date= 2012-11-23 |archive-url= https://web.archive.org/web/20121123023618/http://www.sfgate.com/politics/article/House-votes-to-outlaw-slaughter-of-horses-for-2469915.php |url-status= live }}</ref> Horsehide leather has been used for boots, gloves, [[A-2 jacket|jackets]],<ref name="by-product">{{cite book |last=Ockerman |first=Herbert W. |author2=Hansen, Conly L. |title=Animal By-product Processing & Utilization |year=2000|publisher=CRC Press |location= Lancaster, PA |isbn=1-56676-777-6 |oclc=43685745|page=129}}</ref> [[Baseball (ball)|baseballs]],<ref>{{cite web|url= http://www.baseball-fever.com/showthread.php?p=309566|title= Inside a Modern Baseball|access-date= 2008-04-03|website= Baseball Fever|publisher= Baseball Almanac|archive-date= 2013-08-12|archive-url= https://web.archive.org/web/20130812083051/http://www.baseball-fever.com/showthread.php?3886-Inside-A-Modern-Baseball|url-status= live}}</ref> and baseball gloves. Horse hooves can also be used to produce [[animal glue]].<ref>{{cite book|author=Bartlett, Virginia K.|title=Keeping House: Women's Lives in Western Pennsylvania, 1790–1850|url=https://books.google.com/books?id=L2KtMgwNL3cC&pg=PA35|year=1994|publisher=[[University of Pittsburgh Press]]|isbn=0-8229-5538-5|oclc=30978921|pages=34–35|access-date=2020-09-28|archive-date=2023-03-20|archive-url=https://web.archive.org/web/20230320223818/https://books.google.com/books?id=L2KtMgwNL3cC&pg=PA35|url-status=live}}</ref> Horse bones can be used to make implements.<ref>{{cite book |author= MacGregor, Arthur |title= Bone, Antler, Ivory and Horn: Technology of Skeletal Materials Since the Roman Period |publisher= Barnes & Noble |location= Totowa, NJ |year= 1985 |isbn=0-389-20531-1 |oclc= 11090630|page= 31}}</ref> Specifically, in Italian cuisine, the horse [[tibia]] is sharpened into a probe called a ''spinto'', which is used to test the readiness of a (pig) ham as it cures.<ref>{{cite book|author= Fort, Matthew |title= Eating Up Italy: Voyages on a Vespa |publisher= Centro Books |location= London |year= 2005|isbn= 0-00-721481-2|oclc= 60419304|page= [https://archive.org/details/eatingupitalyvoy0000fort/page/171 171]|url= https://archive.org/details/eatingupitalyvoy0000fort/page/171}}</ref> In Asia, the ''saba'' is a horsehide vessel used in the production of [[kumis]].<ref>{{cite book |translator=Hurd, Edward Payson |title=Diseases of the Stomach and Intestines |year=1886|location=New York |publisher=W. Wood & Company|url=https://archive.org/details/diseasesstomach00dujagoog|page=[https://archive.org/details/diseasesstomach00dujagoog/page/n52 29]}}</ref>

===Care===
{{Main|Horse care}}
{{See also|Equine nutrition|Horse grooming|Veterinary medicine|Farrier}}
[[File:Army.mil-2008-04-18-100048.jpg|thumb|left|Checking teeth and other physical examinations are an important part of horse care.|alt=A young man in US military clothing examines the teeth of a bay (dark brown) horse, while another person in military work clothing, partially obscured, holds the horse. Several other people are partially visible in the background.]]
Horses are [[grazing]] animals, and their major source of nutrients is good-quality [[forage]] from [[hay]] or [[pasture]].<ref>{{cite journal|author=Kellon, Eleanor |title=Focus on Feed Costs |journal=Horse Journal |volume= 16| issue = 6|year=2008|pages=11–12}}</ref> They can consume approximately 2% to 2.5% of their body weight in dry feed each day. Therefore, a {{convert|450|kg|adj=on}} adult horse could eat up to {{convert|11|kg}} of food.<ref name="Penn">{{cite web|author1=Hall, Marvin H.|author2=Patricia M. Comerford|url=http://pubs.cas.psu.edu/FreePubs/pdfs/uc099.pdf|title=Pasture and Hay for Horses&nbsp;– Agronomy Facts 32|year=1992|publisher=University of Pennsylvania |website=Cooperative Extension Service|access-date=2007-02-14|archive-date=2012-12-24|archive-url=https://web.archive.org/web/20121224173129/http://pubs.cas.psu.edu/freepubs/pdfs/uc099.pdf|url-status=dead}}</ref> Sometimes, concentrated feed such as [[Cereal|grain]] is fed in addition to pasture or hay, especially when the animal is very active.<ref>[[#Giffin|Giffin]], pp. 476–477</ref> When grain is fed, equine nutritionists recommend that 50% or more of the animal's diet by weight should still be forage.<ref name="Feeding factors">{{cite web|url=http://ohioline.osu.edu/b762/b762_12.html |archive-url=http://arquivo.pt/wayback/20090708015738/http://ohioline.osu.edu/b762/b762_12.html |url-status=dead |archive-date=2009-07-08 |title=Feeding Factors |publisher=Ohio State University |website=Horse Nutrition |access-date=2007-02-09}}</ref>

Horses require a plentiful supply of clean water, a minimum of {{convert|10|to|12|USgal|L|order=flip}} per day.<ref>[[#Giffin|Giffin]], p. 455</ref> Although horses are adapted to live outside, they require shelter from the wind and [[precipitation]], which can range from a simple shed or shelter to an elaborate [[stable]].<ref>[[#Giffin|Giffin]], p. 482</ref>

Horses require routine [[horse hoof|hoof]] care from a [[farrier]], as well as [[vaccination]]s to protect against various diseases, and [[horse teeth|dental]] examinations from a [[veterinarian]] or a specialized equine dentist.<ref>[[#Giffin|Giffin]], pp. 62, 168, 310</ref> If horses are kept inside in a barn, they require regular daily exercise for their physical health and mental well-being.<ref>{{cite book|author=Harris, Susan E.|title=The United States Pony Club Manual of Horsemanship: Basics for Beginners&nbsp;– D Level|publisher=Howell Book House|location=New York|year=1994|isbn=0-87605-952-3|pages= 160–161}}</ref> When turned outside, they require well-maintained, sturdy [[agricultural fencing|fences]] to be safely contained.<ref>{{cite book |last=Wheeler |first=Eileen |title=Horse Stable And Riding Arena Design |chapter-url=https://books.google.com/books?id=c3dGxSY6E54C&pg=PA215 |year=2006 |publisher=Blackwell Publishing |location=Armes, IA |isbn=978-0-8138-2859-6 |chapter=Fence Planning |oclc=224324847 |page=215 |access-date=2020-09-28 |archive-date=2023-03-20 |archive-url=https://web.archive.org/web/20230320224329/https://books.google.com/books?id=c3dGxSY6E54C&pg=PA215 |url-status=live }}</ref> Regular [[horse grooming|grooming]] is also helpful to help the horse maintain good health of the hair coat and underlying skin.<ref>[[#Giffin|Giffin]], p. 90</ref>

===Climate change===
{{excerpt|Effects of climate change on livestock#Equines}}

{{clear}}

==See also==
* [[Glossary of equestrian terms]]
* [[Lists of horse-related topics]]
* [[List of historical horses]]
* [[Dülmener]]
* [[The horse in Nordic mythology]]
* [[Equus gallicus]]
* [[Solutré horse]]
* [[Horse reform]]

==References==
{{Reflist|refs=

<ref name=EnsmingerHT>{{cite book |last=Ensminger |first=M. Eugene |title=Horses and Tack |edition=Revised |publisher=Houghton Mifflin Company |location=Boston, MA |year=1991 |isbn=0395544130 |oclc=21561287 |ol=1877441M}}</ref>

}}

==Sources==
{{Refbegin|60em}}
* {{cite book |ref=Belknap |author=Belknap, Maria |title=Horsewords: The Equine Dictionary |edition=Second |publisher=Trafalgar Square Publishing |location=North Pomfret, VT |year=2004 |isbn=1-57076-274-0}}
* {{cite book |ref=Bongianni |author=Bongianni, Maurizio |title=Simon & Schuster's Guide to Horses and Ponies |publisher=Fireside |location=New York |year=1987 |isbn=0-671-66068-3 |url=https://archive.org/details/lish00maur }}
* {{cite encyclopedia|ref=Dohner |author=Dohner, Janet Vorwald |editor= Dohner, Janet Vorwald |title=Equines: Natural History |encyclopedia=Historic and Endangered Livestock and Poultry Breeds |year=2001 |publisher=Yale University Press |location=Topeka, KS |pages=400–401 | isbn = 0-300-08880-9}}
* {{cite book|ref=Edwards |author=Edwards, Elwyn Hartley |title=The Encyclopedia of the Horse |publisher=Dorling Kindersley |location= London |year=1994 |isbn=1-56458-614-6 |oclc=29670649}}
* {{cite book |ref=Ensminger |author= Ensminger, M. E.|title= Horses and Horsemanship: Animal Agricultural Series |edition= Sixth |publisher= Interstate Publishers |location= Danville, IN |year= 1990|isbn=0-8134-2883-1 |oclc= 21977751}}
* {{cite book |ref=Giffin |author1=Giffin, James M. |author2=Tom Gore |title=Horse Owner's Veterinary Handbook |edition=Second |publisher=Howell Book House |location=New York |year=1998 |isbn=0-87605-606-0 |oclc=37245445 |url-access=registration |url=https://archive.org/details/horseownersveter0002giff }}
* {{cite book|ref=Harris |author= Harris, Susan E. |title= Horse Gaits, Balance and Movement |publisher= Howell Book House| location= New York |year=1993 |isbn=0-87605-955-8 |oclc= 25873158}}
* {{cite book |ref=McBane |title=The Illustrated Encyclopedia of Horse Breeds |last=McBane |first=Susan |year=1997 |publisher=Wellfleet Press |location=Edison, NJ |isbn=0-7858-0604-0 |oclc=244110821 |url=https://archive.org/details/illustratedencyc00susa }}
* {{cite book|ref=Miller|author=Miller, Robert M.|title=Understanding the Ancient Secrets of the Horse's Mind|publisher=Russell Meerdink Company Ltd|location=Neenah, WI|year=1999|isbn=0-929346-65-3|url=https://books.google.com/books?id=5Qat2gs43owC&pg=PA28|oclc=42389612|access-date=2020-09-28|archive-date=2023-03-20|archive-url=https://web.archive.org/web/20230320224329/https://books.google.com/books?id=5Qat2gs43owC&pg=PA28|url-status=live}}
* {{cite book|ref=Price |editor1= Price, Steven D.|editor2= Spector, David L. |editor3= Rentsch, Gail|editor4= Burn, Barbara B. |title= The Whole Horse Catalog: Revised and Updated |edition=Revised |publisher=Fireside |location=New York |year=1998 |isbn=0-684-83995-4}}
* {{cite book|ref= Sponenberg|author= Sponenberg, D. Phillip|chapter= The Proliferation of Horse Breeds|title= Horses Through Time|edition= First|publisher= Roberts Rinehart Publishers|location= Boulder, CO|year= 1996|isbn= 1-57098-060-8|oclc= 36179575|chapter-url= https://archive.org/details/horsesthroughtim00olse|url-access= registration|url= https://archive.org/details/horsesthroughtim00olse}}
* {{cite book|ref=Whitaker | author=Whitaker, Julie |author2=Whitelaw, Ian |title=The Horse: A Miscellany of Equine Knowledge |publisher=St. Martin's Press |location=New York |year=2007 |isbn=978-0-312-37108-1}}
{{Refend}}

==Further reading==
{{Refbegin}}
* {{cite book |author= Chamberlin, J. Edward |title= Horse: How the Horse Has Shaped Civilizations |publisher= Bluebridge |location= New York |year= 2006|isbn=978-0-9742405-9-6 |oclc= 61704732}}
{{Refend}}

==External links==
{{Wikispecies|Equus caballus}}
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* [https://www.bbc.co.uk/news/science-environment-23060993 "Ancient horse bone yields oldest DNA sequence"]
* {{Cite NIE|wstitle=Horse|short=x}}
* {{Cite EB1911|wstitle=Horse|short=x}}
* [https://www.ensembl.org/Equus_caballus/Info/Index Genome of ''Equus caballus''], via [[Ensembl]]
* [https://genome.ucsc.edu/cgi-bin/hgTracks?db=equCab3&lastVirtModeType=default&lastVirtModeExtraState=&virtModeType=default&virtMode=0&nonVirtPosition=&position=chr11%3A53042266%2D53660035&hgsid=1430148309_s0mIqHUNKBbB06Tlt0mlYt0ZUJqr Genome of ''Equus caballus'' (version EquCab3.0/equCab3)], via [[UCSC Genome Browser]]
* [https://www.ncbi.nlm.nih.gov/genome/145 Data of the genome of ''Equus caballus''], via [[NCBI]]
* [https://www.ncbi.nlm.nih.gov/assembly/GCF_002863925.1/ Data of the genome assembly of ''Equus caballus'' (versión EquCab3.0/equCab3)], via [[NCBI]]

{{Perissodactyla}}
{{Horse topics}}
{{Working animals}}
{{Subject bar |portal1=Horses |commons=y |commons-search=Horses |q=y |q-search=Horses}}
{{Taxonbar|from=Q726}}
{{Authority control}}

[[Category:Horses| ]]
[[Category:Animal-powered transport]]
[[Category:Mammals described in 1758]]
[[Category:Taxa named by Carl Linnaeus]]
[[Category:Equus (genus)]]
[[Category:Herbivorous mammals]]
[[Category:Horse subspecies]]
[[Category:Livestock]]
[[Category:National symbols of Burkina Faso]]
[[Category:National symbols of Lesotho]]
[[Category:National symbols of Mongolia]]
[[Category:National symbols of Nigeria]]
[[Category:National symbols of Turkmenistan]]
[[Category:Pack animals]]
[[Category:Symbols of New Jersey]]