Editing Przewalski's horse (section)

==Population==
===History===
[[File:Anneau, M.C. 8756.jpg|thumb|upright|Przewalski's horse on bronze ring made in Northern [[Hebei]] and Western [[Liaoning]]. 6th-5th century BCE. [[Musée Cernuschi]]]]
Przewalski's-type wild horses appear in European cave art dating as far back as 20,000 years ago,<ref name=IUCN/> but genetic investigation of a 35,870-year-old specimen from one such cave instead showed an affinity with extinct Iberian horse lineage and the modern domestic horse, suggesting that it was not Przewalski's horse being depicted in this art.<ref>{{cite journal|first1=Antoine |last1=Fages |first2=Kristian |last2=Hanghøj |first3=Naveed |last3=Khan |display-authors=etal |title=Tracking Five Millennia of Horse Management with Extensive Ancient Genome Time Series |journal=Cell |year=2019 |volume=177 |issue=6 |pages=1419–1435 |doi=10.1016/j.cell.2019.03.049|pmid=31056281 |pmc=6547883 |doi-access=free }}</ref> Horse skeletons dating to the fifth to the third millennia BCE, found in Central Asia, with a range extending to the southern [[Ural Mountains|Urals]] and the [[Altai Mountains|Altai]], belong to the genetic lineage of Przewalski's horse.<ref>{{cite journal |last1=Librado |first1=Pablo |last2=Khan |first2=Naveed |last3=kusliy |first3=Mariya A.|display-authors=etal |title=The origins and spread of domestic horses from the Western Eurasian steppes |journal=Nature |year=2021 |volume=596 |issue=7882 |pages=634–640 |doi=10.1038/s41586-021-04018-9|pmid=34671162 |pmc=8550961 |bibcode=2021Natur.598..634L |s2cid=239050837 }}</ref> Of particular note are the horses of this lineage found in the archaeological sites of the [[Chalcolithic]] Botai culture. Sites dating from the mid-fourth-millennium BCE show evidence of horse domestication.<ref>{{cite journal|first1=Alan K |last1=Outram |first2=Natalie A |last2=Stear |first3=Robin |last3=Bendrey |first4=Sandra |last4=Olsen |first5=Alexei |last5=Kasparov |first6=Victor |last6=Zaibert |first7=Nick |last7=Thorpe |first8=Richard P |last8=Evershed |title=The Earliest Horse Harnessing and Milking |journal=Science |volume=323 |pages=1332–1335 |year=2009 |issue=5919 |doi=10.1126/science.1168594|pmid=19265018 |bibcode=2009Sci...323.1332O |s2cid=5126719 }}</ref> Analysis of ancient DNA from Botai horse specimens from about 3000 BCE reveals them to have DNA markers consistent with the lineage of modern Przewalski's horses.<ref name="sciencemag.org"/>

There are sporadic reports of Przewalski's horse in the historical record before its formal characterization. The Buddhist monk Bodowa wrote a description of what is thought to have been Przewalski's horse about AD 900,<ref name=isotope /> and an account from 1226 reports an incident involving wild horses during [[Genghis Khan]]'s campaign against the [[Western Xia|Tangut empire]].<ref name=IUCN/>  In the fifteenth century, [[Johann Schiltberger]] recorded one of the first European sightings of the horses in the journal recounting his trip to Mongolia as a prisoner of the [[Mongol]] [[Khan (title)|Khan]].<ref>{{cite web |url=http://afs.okstate.edu/breeds/horses/przewalski |series=Breeds of Livestock |title=Przewalski Horse |website=Breeds of Livestock, Department of Animal Science |publisher= Oklahoma State University |access-date=2019-04-29 |url-status=live |archive-url=https://web.archive.org/web/20141017090523/http://www.ansi.okstate.edu/breeds/horses/przewalski/index.htm |archive-date=17 October 2014 |df=dmy-all}}</ref> Another was recorded as a gift to the Manchurian emperor around 1630, its value as a gift suggesting a difficulty in obtaining them.<ref name=boyd94/> [[John Bell (traveller)|John Bell]], a Scottish doctor in service to [[Peter the Great]] from 1719 to 1722, observed a horse in Russia's [[Tomsk Oblast]] that was apparently this species,<ref name=isotope /> and a few decades later in 1750, a large hunt with thousands of beaters organized by the Manchurian emperor killed between two and three hundred of these horses.<ref name=boyd94/>
[[File:Przewalski horse skull 01.JPG|thumb|Przewalski's horse skull, Brno museum]]
The species is named after a Russian colonel of Polish descent, [[Nikolai Przhevalsky]] (1839–1888) (Nikołaj Przewalski in Polish). An explorer and naturalist, he obtained the skull and hide of an animal shot in 1878 in the Gobi near today's China–Mongolia border. He would travel to the Dzungarian Basin to observe it in the wild.<ref name=isotope /> In 1881, the horse received a formal scientific description and was named ''Equus przevalskii'' by Ivan Semyonovich Polyakov, based on Przewalski's collection and description,<ref name=isotope /><ref name=Nature /> while in 1884, the sole exemplar of the horse in Europe was a preserved specimen in the [[Zoological Museum of the Zoological Institute of the Russian Academy of Sciences|Museum of the Russian Academy of Sciences]] in [[St. Petersburg]].<ref name=Nature /> This was supplemented in 1894 when the brothers Grum-Grzhimailo returned several hides and skulls to St. Petersburg and described the horse's behavior in the wild.<ref name=boyd94/> A number of these horses were captured around 1900 by [[Carl Hagenbeck]] and placed in zoos, and these, along with one later captive, reproduced to give rise to today's population.

After 1903, there were no reports of the wild population until 1947, when several isolated groups were observed and a lone [[filly]] captured. Although local herdsmen reported seeing as many as 50 to 100 takhis grazing in small groups then, there were only sporadic sightings of single groups of two or three animals after that, mostly near natural wells.<ref name=boyd94/> Two scientific expeditions in 1955 and 1962 failed to find any. After herders and naturalists reported single harem groups in 1966 and 1967, the last observation of the wild horse in its native habitat was of a single stallion in 1969.<ref name=boyd94/><ref name=Fijn /> Expeditions after this failed to locate any horses, and the species would be designated "extinct in the wild" for over 30&nbsp;years.<ref name=boyd94/> Competition with livestock, hunting, capture of foals for zoological collections, military activities, and harsh winters recorded in 1945, 1948, and 1956 are considered to be main causes of the decline in Przewalski's horse population.<ref name=GBE2011 />

The wild population was already rare at its first scientific characterization. Przewalski reported seeing them only from a distance and may have instead sighted herds of local [[onager]] Mongolian wild asses. He was only able to obtain specimens of the type from Kirghiz hunters.<ref name=Fijn />  The range of Przewalski's horse was limited to the arid [[Gobi Desert#Dzungaria Basin semi-desert|Dzungarian Basin]] in the [[Gobi Desert]].<ref name=Nature>"Przevalsky's Wild Horse", ''Nature'', 30:391-392 (1884).</ref> It has been suggested that this was not their natural habitat, but, like the onager, they were a steppe animal driven to this barren last refuge by the dual pressures of hunting and habitat loss to agricultural grazing.<ref name=isotope>{{cite journal |first1=Petra |last1=Kaczensky |first2=Martina |last2=Burnik Šturm |first3=Mikhail V. |last3=Sablin |first4=Christian C. |last4=Voigt |first5=Steve |last5=Smith |first6=Oyunsaikhan |last6=Ganbaatar |first7=Boglarka |last7=Balint |first8=Chris |last8=Walzer |first9=Natalia N. |last9=Spasskaya |title=Stable isotopes reveal diet shift from pre-extinction to reintroduced Przewalski's horses |journal=Scientific Reports |volume=7 |page=5950 |year=2017 |issue=1 |doi=10.1038/s41598-017-05329-6|pmid=28729625 |pmc=5519547 |bibcode=2017NatSR...7.5950K }}</ref> There were two distinct populations recognized by local Mongolians, a lighter steppe variety and a darker mountain one. This distinction is seen in early twentieth-century descriptions. Their mountainous habitat included the ''Takhiin Shar Nuruu'' (The Yellow Wild-Horse Mountain Range).<ref name=Fijn>{{cite book |last=Fijn |first=Natasha |chapter=13. The domestic and the wild in the Mongolian horse and the takhi |title= Taxonomic Tapestries: The Threads of Evolutionary, Behavioural and Conservation Research |editor1-last=Behie |editor1-first=Alison M |editor2-last=Ozenham |editor2-first=Marc F |year=2015 |publisher=ANU Press, The Australian National University |location=Canberra |pages=279–298 |doi=10.22459/TT.05.2015.13 |doi-access=free }}</ref> In their last decades in the wild, the remnant population was limited to the small region between the Takhiin Shar Nuruu and Bajtag-Bogdo mountain ridges.<ref name=boyd94 />

===Captivity===
[[File:Equus ferus przewalskii 2.jpg|thumb|Vaska, a Przewalski horse trained to be ridden]]
Attempts to obtain specimens for exhibit and [[captive breeding]] were largely unsuccessful until 1902, when 28&nbsp;captured foals were brought to Europe. These and a small number of additional captives would be distributed among zoos and breeding centers in Europe and the United States. Many facilities failed in their attempts at captive breeding, but a few programs were established. However, by the mid-1930s, inbreeding had caused reduced fertility, and the captive population experienced a [[genetic bottleneck]], with the surviving captive breeding stock descended from only 11 of the founder captives.<ref name=boyd94/> In addition, in at least one instance, the progeny of interbreeding with a domestic horse was bred back into the captive Przewalski's horse population. However, recent studies have shown only minimal genetic contribution of this domestic horse to the captive population.<ref name=Bowling>{{cite journal |last1=Bowling |first1=Ann T. |last2=Ryder |first2=Oliver A. |title=Genetic studies of blood markers in Przewalski's horse |journal=The Journal of Heredity |volume=78 |issue=2 |pages=75–80 |year=1987 |url=http://cricket.biol.sc.edu/papers/horses/Genetic%20studies%20of%20blood%20markers%20in%20przewalski%27s%20horses.pdf |doi=10.1093/oxfordjournals.jhered.a110340 |pmid=3584938 |archive-date=18 May 2021 |access-date=21 April 2019 |archive-url=https://web.archive.org/web/20210518235306/http://cricket.biol.sc.edu/papers/horses/Genetic%20studies%20of%20blood%20markers%20in%20przewalski%27s%20horses.pdf |url-status=live }}</ref>

The situation was improved when the exchange of breeding animals among facilities increased genetic diversity and there was a consequent improvement in fertility, but the population experienced another genetic bottleneck when many of the horses failed to survive World War&nbsp;II. The most valuable group, in [[Askania Nova]], [[Ukraine]], was shot by German soldiers during [[World War&nbsp;II]] occupation, and the group in the United States had died out.<ref name=GBE2011 /> Only two captive populations in zoos remained, in [[Tierpark Hellabrunn|Munich]] and in [[Prague Zoo|Prague]], and of the 31&nbsp;remaining horses at war's end, only 9 became ancestors of the subsequent captive population.<ref name=boyd94/> By the end of the 1950s, only 12&nbsp;individual horses were left in the world's zoos.<ref name=GBE2011 />

A wild-caught mare captured as a foal a decade earlier was introduced into the Ukrainian captive population in 1957. This would prove the last wild-caught horse, and with the presumed extinction of the wild population, last sighted in Mongolia in the late 1960s, the captive population became the sole representatives of Przewalski's horse.<ref name=boyd94/>  Genetic diversity received a much-needed boost from this new source, with the spread of her bloodline through the inbred captive groups leading to their increased reproductive success, and by 1965, there were more than 130 animals spread among thirty-two zoos and parks.

===Conservation efforts===
[[File:Przewalski's Horse (02710137).jpg|thumb|Przewalski's horse in the Chernobyl Exclusion Zone]]

In 1977, the Foundation for the Preservation and Protection of the Przewalski Horse was founded in [[Rotterdam]], the Netherlands, by Jan and Inge Bouman. The foundation started a program of exchange between captive populations in zoos worldwide to reduce [[inbreeding]] and later began its own breeding program. As a result of such efforts, the extant herd has retained a far greater genetic diversity than its [[Population bottleneck|genetic bottleneck]] made likely.<ref name=GBE2011 />  By 1979, when this concerted program of population management to maximize [[genetic diversity]] was begun, there were almost four hundred horses in sixteen facilities,<ref name=boyd94/> a number that had grown by the early 1990s to over 1,500.<ref name=ZSL051219/>

While dozens of zoos worldwide have Przewalski's horses in small numbers, specialized reserves are also dedicated primarily to the species. The world's largest captive-breeding program for Przewalski's horses is at the [[Askania Nova]] preserve in Ukraine. From 1998, thirty-one horses were also released in the unenclosed [[Chernobyl Exclusion Zone]] in [[Ukraine]] and [[Belarus]]. People evacuated the zone after the [[Chernobyl accident]], so now it serves as a deserted ''[[de facto]]'' nature reserve.<ref name=bbc060420/> Though poaching has taken a toll on numbers,<ref>{{cite web |last=Gill |first=Victoria |date=27 July 2011 |title=Chernobyl's Przewalski's horses are poached for meat |url=http://www.bbc.co.uk/nature/14277058 |website=[[BBC|BBC Nature]] |access-date=2 May 2016 |df=dmy-all|archive-url=https://web.archive.org/web/20180427213925/http://www.bbc.co.uk/nature/14277058 |archive-date=27 April 2018}}</ref> as of 2019 the estimated population in the Chernobyl zone was over 100 individuals.<ref>{{Cite web|url=https://glavcom.ua/kyiv/news/u-chornobilskiy-zoni-prizhilisya-koni-przhevalskogo-foto-539517.html|title=У Чорнобильській зоні прижилися коні Пржевальського|date=26 October 2018|access-date=26 April 2020|archive-date=11 April 2021|archive-url=https://web.archive.org/web/20210411144702/https://glavcom.ua/kyiv/news/u-chornobilskiy-zoni-prizhilisya-koni-przhevalskogo-foto-539517.html|url-status=live}}</ref><ref>{{cite web | url=http://dazv.gov.ua/novini-ta-media/vsi-novyny/chornobilskij-zapovidnik-spilno-z-kijivskim-zooparkom-vivchayut-dikikh-konej-przhevalskogo-u-zoni-vidchuzhennya.html | title=Чорнобильський заповідник спільно з Київським зоопарком вивчають диких коней Пржевальського у зоні відчуження | access-date=3 September 2022 | archive-date=26 July 2019 | archive-url=https://web.archive.org/web/20190726144020/http://dazv.gov.ua/novini-ta-media/vsi-novyny/chornobilskij-zapovidnik-spilno-z-kijivskim-zooparkom-vivchayut-dikikh-konej-przhevalskogo-u-zoni-vidchuzhennya.html | url-status=bot: unknown }}</ref><ref>{{Cite news|url = https://www.bbc.com/ukrainian/news-52400959|title = У Чорнобилі знайшли обгоріле лоша. Тепер лікують у притулку|newspaper = BBC News Україна|archive-date = 7 November 2021|access-date = 26 April 2020|archive-url = https://web.archive.org/web/20211107151201/https://www.bbc.com/ukrainian/news-52400959|url-status = live}}</ref><ref>{{cite web|url=https://zora-irpin.info/zavezeni-z-mongoliyi-koni-przhevalskogo-prizhilisya-u-zoni-vidchuzhennya-chaes/|website=zora-irpin.info|title=Завезені з Монголії коні Пржевальського прижилися у зоні відчуження ЧАЕС|date=19 February 2020|language=uk}}</ref><ref name="ngWJ">{{cite web|last1=Wendle |first1=John |title=Animals Rule Chernobyl 30 Years After Nuclear Disaster |url=http://news.nationalgeographic.com/2016/04/060418-chernobyl-wildlife-thirty-year-anniversary-science/ |archive-url=https://web.archive.org/web/20160418224940/http://news.nationalgeographic.com/2016/04/060418-chernobyl-wildlife-thirty-year-anniversary-science/ |url-status=dead |archive-date=18 April 2016 |website=National Geographic |date=18 April 2016 |access-date=2 May 2016}}</ref>

Le Villaret, located in the Cevennes National Park in southern France and run by the Association Takh, is a breeding site for Przewalski's horses that was created to allow the free expression of natural Przewalski's horse behaviors. In 1993, eleven zoo-born horses were brought to Le Villaret. Horses born there are adapted to life in the wild, free to choose their mates, and required to forage independently. This was intended to produce individuals capable of being reintroduced into Mongolia. In 2012, 39 individuals were at Le Villaret.<ref name=takhleaflet/> An intensely researched population of free-ranging animals was also introduced to the [[Hortobágy National Park]] ''[[puszta]]'' in Hungary; data on social structure, behavior, and diseases gathered from these animals are used to improve the Mongolian conservation effort.<ref name=Kerekes /> An additional breeding population of Przewalski's horses roams the former Döberitzer Heide military [[proving ground]], now a nature reserve in [[Dallgow-Döberitz]], Germany. Established in 2008, this population comprised 24 horses in 2019.<ref>{{Cite web|date=2019-03-25|title=Die Przewalski-Pferde in der Döberitzer Heide|url=https://www.doris-semmelmann.de/die-przewalski-pferde-in-der-doeberitzer-heide-2627/|access-date=2021-01-18|language=de-DE|archive-date=24 January 2021|archive-url=https://web.archive.org/web/20210124155955/https://www.doris-semmelmann.de/die-przewalski-pferde-in-der-doeberitzer-heide-2627/|url-status=live}}</ref> Another population is being established in the [[Sistema Ibérico|Iberian System]] in Spain, the first free-roaming Przewalski’s horses in Western Europe.<ref>{{Cite web |date=2023-11-30 |title=La renaturalización trae al Alto Tajo los únicos caballos Przewalski que pastarán en libertad en Europa Occidental |url=https://rewilding-spain.com/en/news/rewilding-brings-to-the-iberian-highlands-the-first-free-roaming-przewalskis-horses-in-western-europe/ |access-date=2024-05-05 |website=Rewilding Spain |language=en-GB}}</ref>

In 2024, a [[Colorado]] rancher discovered what appears to be a Przewalski's horse at a [[Kansas]] livestock auction,<ref>{{Cite news|date=2023-11-30|title='Ferrari in a junkyard': Mules sold at auction are rare, endangered horses|url=https://www.washingtonpost.com/climate-environment/2024/08/09/przewalskis-horses-rescued-dna-shrek-fiona/|access-date=2024-08-10|newspaper=Washington Post|language=en-US|archive-date=11 August 2024|archive-url=https://web.archive.org/web/20240811122911/https://www.washingtonpost.com/climate-environment/2024/08/09/przewalskis-horses-rescued-dna-shrek-fiona/|url-status=live}}</ref> mistakenly identified as a mule. Another similar horse was found at a [[Utah]] sanctuary. Genetic tests suggest both are Przewalski's horses, raising concerns about how they ended up in U.S. auctions.<ref name=":2">{{Cite web |url=https://www.nytimes.com/2024/10/23/nyregion/rare-horses-przewalski.html |title=How Two of the Rarest Horses on Earth Got Lost |work=The New York Times |date=23 October 2024 |access-date=23 October 2024 |archive-date=28 October 2024 |archive-url=https://web.archive.org/web/20241028014537/https://www.nytimes.com/2024/10/23/nyregion/rare-horses-przewalski.html/ |url-status=live |last1=Nir |first1=Sarah Maslin }}</ref> One horse, Fiona, was euthanized following apparent organ failure, while the other's fate is unreported.<ref name=":2" />

===Reintroduction===
[[File:Group of Takhi at Hustai.jpg|thumb|Przewalski's horses in Hustai Nuruu National Park]]
The Przewalski's Horse Reintroduction Project of China was initiated in 1985 when 11&nbsp;wild horses were imported from overseas. After more than two decades of effort, the [[Xinjiang]] Wild Horse Breeding Centre has bred a large number of horses, 55 of which were released into the [[Kalamely Mountain]] area. The animals quickly adapted to their new environment. In 1988, six foals were born and survived, and by 2001, over 100&nbsp;horses were at the centre. {{As of|2013}}, the center hosted 127 horses divided into 13&nbsp;breeding herds and three bachelor herds.{{cn|date=June 2024}} 

Reintroductions organized by Western European countries started in the 1990s. Several populations have now been released into the wild. A cooperative venture between the [[Zoological Society of London]] and Mongolian scientists has successfully reintroduced these horses from zoos into their natural habitat in Mongolia.  In 1992, 16 horses were released into the wild in Mongolia, followed by additional animals later. One of the areas to which they were reintroduced became [[Khustain Nuruu National Park]] in 1998. Another reintroduction site is [[Great Gobi&nbsp;B Strictly Protected Area]], located at the fringes of the [[Gobi Desert]].{{cn|date=June 2024}} 

In 2001, Przewalski's horses were reintroduced into the [[Kalamaili Nature Reserve]] in [[Xinjiang]], China.<ref name=Xinjiang>{{cite journal | last1=Chen | first1=Jinliang | last2=Weng | first2=Qiang | last3=Chao| first3=Jie | last4=Hu| first4=Defu | last5=Taya | first5=Kazuyoshi | title=Reproduction and Development of the Released Przewalski's Horses (''Equus przewalskii'') in Xinjiang, China | journal=Journal of Equine Science | volume=19 | issue=1 | pages=1–7 | year=2008 | doi=10.1294/jes.19.1 | pmid=24833949 | pmc=4019202}}</ref>  

Since 2004, there has been a program to reintroduce Przewalski's horses that were bred in France into Mongolia.<ref>{{cite web |url=https://news.nationalgeographic.com/2016/11/Claudia-Feh-explorer-moments-reintroducing-endangered-Przewalski-horses-into-the-wild/ |archive-url=https://web.archive.org/web/20161118125158/http://news.nationalgeographic.com/2016/11/Claudia-Feh-explorer-moments-reintroducing-endangered-Przewalski-horses-into-the-wild/ |url-status=dead |archive-date=18 November 2016 |title=A Wild Horse on the Comeback Trail |first=Gary |last=Strauss |work=National Geographic |date=2016-11-17 |access-date=2019-04-14 |df=dmy-all}}</ref> Instrumental to that 2004 reintroduction was [[Claudia Feh]], a Swiss equine specialist and conservation biologist, Feh led an effort to bring together animals that zoos had conserved to create a breeding population in southern France. Then, after it was established, three family groups were relocated to [[Khovd Province|Khovd]] in western Mongolia. At a site on the northern edge of the [[Gobi Desert]], Feh worked in cooperation with local people to ensure the horses survived and flourished. For this work, Feh received a [[Rolex Awards for Enterprise#2004|Rolex Award]] in 2004.<ref>{{cite web
	| url = https://www.rolex.org/rolex-awards/environment/claudia-feh
	| title = Claudia Feh: Wild Horses And Nomads
	| date = 2004
	| website = Rolex Awards
	| access-date = April 15, 2024
	| quote = Przewalski's horses had disappeared from the Mongolian steppes by the 1970s but Claudia Feh led one of several initiatives reintroducing them to the habitat they had ranged for centuries – and improved the lives of local nomads in the process.
	| archive-date = 3 March 2024
	| archive-url = https://web.archive.org/web/20240303054147/https://www.rolex.org/rolex-awards/environment/claudia-feh
	| url-status = live
	}}</ref>

In 2004 and 2005, 22&nbsp;horses were released by the Association Takh to a third reintroduction site in the buffer zone of the [[Khar Us Nuur National Park]], in the northern edge of the Gobi ecoregion. In the winter of 2009–2010, one of the worst ''[[dzud]]'' or snowy winter conditions ever hit Mongolia. The population of Przewalski's horse in the Great Gobi B SPA was drastically affected, providing clear evidence of the risks associated with reintroducing small and sequestered species in unpredictable and unfamiliar environments.{{citation needed|date=March 2021|reason=According to whom?}} 

After reintroduced horses had successfully reproduced, the status of the animal was changed from "extinct in the wild" to "[[endangered species |endangered]]" in 2005,<ref name=ZSL051219/> while on the [[IUCN Red List]] they were reclassified from "extinct in the wild" to "[[critically endangered]]", after a reassessment in 2008,<ref name=IUCN/> and from "critically endangered" to "endangered" after a 2011 reassessment.<ref name=IUCN2011/> 

In 2011, [[Prague Zoo]] started a new project, [[Return of the Wild Horses]]. With the support of public and many strategic partners, yearly transports of captive-bred horses into the [[Great Gobi B Strictly Protected Area]] continued.<ref>{{cite web |title=Return of the Przewalski's Horse to Mongolia |url=https://www.zoopraha.cz/en/animals/we-help-them-to-survive/projects/7678-return-of-the-przewalski-s-horse-to-mongolia |website=Zoo Praha |access-date=2019-06-27 |df=dmy-all |language=en}}</ref>  {{As of|2011|lc=y}}, an estimated total of almost 400&nbsp;horses existed in three free-ranging populations in the wild.<ref name=IUCN2011/> Prague Zoo has transported horses to Mongolia in several rounds in cooperation with partners (Czech Air Force, European Breeding Programme for Przewalski's Horses, Association pour le cheval de Przewalski: Takh, Czech Development Agency, Czech Embassy in Mongolia, and others). The zoo has the longest uninterrupted history of breeding Przewalski's horses in the world and keeps the studbook of this species.{{cn|date=June 2024}} 

The first reintroduction into the [[Orenburg Oblast|Orenburg]] region on the Russian steppe occurred in 2016.<ref>{{cite news| last=Blua | first=Antoine | title=Endangered Przewalski's Horses Back On Russian Steppe | date=13 March 2016 | access-date=17 December 2020 | publisher=RadioFreeEurope | url=https://www.rferl.org/a/endangered-horses-back-on-russian-steppe/27607786.html}}</ref><ref>{{cite journal | last1=Bakirova | first1=Rafilia T | last2=Sharkikh | first2=Tatjana | title=Programme on establishing a semi-free population of Przewalski's horse in Orenburg State Nature Reserve: the first successful project on the reintroduction of the species in Russia | journal=Nature Conservation Research | volume=4 | issue=Supplement 2 | pages=57–64  | year=2019| doi=10.24189/ncr.2019.025| doi-access=free | url=https://cyberleninka.ru/article/n/programme-on-establishing-a-semi-free-population-of-przewalski-s-horse-in-orenburg-state-nature-reserve-the-first-successful-project-on-the/pdf }}</ref> 

In May 2023, a herd of ten Przewalski's horses obtained from [[Monts D'Azur Biological Reserve]] in France was introduced by [[Rewilding Europe]] to the Iberian Highlands rewilding landscape in Spain, near [[Villanueva de Alcorón]]. Following an acclimatization period, the horses were released into the reserve proper in September. This introduction was intended to address the buildup of dense scrub caused by the decrease in traditional sheep grazing due to rural depopulation. The horses are intended to fill a niche similar to that of the extinct European wild horse and of contemporary domesticated [[herbivore]]s by opening the landscape through low-intensity grazing and browsing, thereby enhancing biodiversity and lowering the risk of [[forest fire]]s. Future introductions are planned.<ref>{{cite news | title=How an Iberian rewilding plan aims to repopulate 'empty Spain' | date=7 July 2023 | access-date=29 October 2023 | work=[[The Guardian]] | url=https://www.theguardian.com/world/2023/jul/07/iberian-rewilding-project-aims-repopulate-empty-spain | archive-date=4 August 2023 | archive-url=https://web.archive.org/web/20230804042614/https://www.theguardian.com/world/2023/jul/07/iberian-rewilding-project-aims-repopulate-empty-spain | url-status=live }}</ref><ref>{{cite news | title=Western Europe's first free-roaming herd of Przewalski's horses to enhance Iberian Highland rewilding | date=8 July 2023 | access-date=29 October 2023 | publisher=[[Rewilding Europe]] | url=https://rewildingeurope.com/news/western-europes-first-free-roaming-herd-of-przewalskis-horses-to-enhance-iberian-highland-rewilding/ | archive-date=10 July 2023 | archive-url=https://web.archive.org/web/20230710092015/https://rewildingeurope.com/news/western-europes-first-free-roaming-herd-of-przewalskis-horses-to-enhance-iberian-highland-rewilding/ | url-status=live }}</ref> 

In June 2024 six mares and a stallion were reintroduced to [[Kazakhstan]] from zoos in Europe,<ref name="Grdn2024">{{cite news |last1=Kevany |first1=Sophie |title=Wild horses return to Kazakhstan steppes after absence of two centuries |url=https://www.theguardian.com/environment/article/2024/jun/10/przewalskis-horses-only-wild-species-return-central-asian-steppes-kazakhstan |access-date=12 June 2024 |work=The Guardian |date=10 June 2024}}</ref> ten years after plans were announced to do so.<ref>{{cite news |last=Rutz |first=Julia |title=Effort Begins to Revive Endangered Przewalski Horse Population in Kazakhstan |date=11 November 2014 |access-date=18 December 2020 |publisher=Astana Times |url=https://astanatimes.com/2014/11/effort-begins-revive-endangered-przewalski-horse-population-kazakhstan/ |archive-date=14 May 2021 |archive-url=https://web.archive.org/web/20210514184846/https://astanatimes.com/2014/11/effort-begins-revive-endangered-przewalski-horse-population-kazakhstan/ |url-status=live }}</ref> The operation was organised by [[Prague Zoo]], which selected horses from various programs in Europe, which were housed at [[Tierpark Berlin]] for some months before being transported to Kazakhstan in Czech army planes.<ref>{{cite web | last=Mao | first=Frances | title=Przewalski's horses return to Kazakhstan steppes after 200 years | website=BBC News | date=13 June 2024 | url=https://www.bbc.com/news/articles/cljj0y15nnko | access-date=13 June 2024}}</ref>

===Assisted reproduction and cloning===
[[File:Przewalski 26-9-2004-3.jpg|thumb|right|Przewalski's horses]]
In the earlier decades of captivity, the insular breeding by individual zoos led to inbreeding and reduced fertility. In 1979, several American zoos began a collaborative breeding-exchange program to maximize genetic diversity.<ref name=BC8204/> Recent advances in equine reproductive science have also been used to preserve and expand the gene pool. Scientists at the [[Smithsonian Institution]]'s [[National Zoological Park (United States)|National Zoo]] successfully reversed a [[vasectomy]] on a Przewalski horse in 2007—the first operation of its kind on this species, and possibly the first ever on any endangered species. While normally, a vasectomy may be performed on an endangered animal under limited circumstances, particularly if an individual has already produced many offspring and its genes are overrepresented in the population, scientists realized the animal in question was one of the most genetically valuable Przewalski's horses in the North American breeding program.<ref name=AP080617/> The first birth by [[artificial insemination]] occurred on 27 July 2013 at the [[Smithsonian Conservation Biology Institute]].<ref name=PHAI/><ref>{{cite magazine |title=First Przewalski's Horse Born Via Artificial Insemination |date=5 August 2013 |url=http://news.nationalgeographic.com/news/2013/13/130805-przewalski-horse-born-artificial-insemination-animal-science/ |archive-url=https://web.archive.org/web/20130807120240/http://news.nationalgeographic.com/news/2013/13/130805-przewalski-horse-born-artificial-insemination-animal-science/ |url-status=dead |archive-date=7 August 2013 |magazine=National Geographic |access-date=14 August 2013 |last=Shenk |first=Emily |df=dmy-all}}</ref>

In 2020, the first cloned Przewalski's horse was born, the result of a collaboration between [[San Diego Zoo Global]], [[ViaGen Pets|ViaGen Equine]] and [[Revive & Restore]].<ref name=":0">{{Cite web|title=Przewalski's Horse (Takhi) Project {{!}} Revive & Restore|url=https://reviverestore.org/projects/przewalskis-horse/|access-date=2020-11-15|language=en-US|archive-date=8 September 2020|archive-url=https://web.archive.org/web/20200908050955/https://reviverestore.org/projects/przewalskis-horse/|url-status=live}}</ref> The [[cloning]] was carried out by [[somatic cell nuclear transfer]] (SCNT), whereby a viable [[embryo]] is created by transplanting the [[DNA]]-containing [[Cell nucleus|nucleus]] of a [[somatic cell]] into an immature egg cell ([[oocyte]]) that has had its nucleus removed, producing offspring genetically identical to the somatic cell donor.<ref>{{Cite journal|last1=Tian|first1=X. Cindy|last2=Kubota|first2=Chikara|last3=Enright|first3=Brian|last4=Yang|first4=Xiangzhong|date=2003-11-13|title=Cloning animals by somatic cell nuclear transfer – biological factors|url= |journal=Reproductive Biology and Endocrinology|volume=1|issue=1|pages=98|doi=10.1186/1477-7827-1-98|issn=1477-7827|pmc=521203|pmid=14614770 |doi-access=free }}</ref> Since the oocyte used was from a domestic horse, this was an example of interspecies SCNT.<ref>{{Cite journal|last1=Lagutina|first1=Irina|last2=Fulka|first2=Helena|last3=Lazzari|first3=Giovanna|last4=Galli|first4=Cesare|date=October 2013|title=Interspecies Somatic Cell Nuclear Transfer: Advancements and Problems|journal=Cellular Reprogramming|volume=15|issue=5|pages=374–384|doi=10.1089/cell.2013.0036|issn=2152-4971|pmc=3787369|pmid=24033141}}</ref>

The somatic cell donor was a Przewalski horse stallion named Kuporovic, born in the UK in 1975 and relocated three years later to the US, where he died in 1998. Due to concerns over the loss of [[genetic variation]] in the captive Przewalski's horse population, and in anticipation of the development of new cloning techniques, tissue from the stallion was [[cryopreserved]] at the San Diego Zoo's [[Frozen zoo|Frozen Zoo]]. Breeding of this individual in the 1980s had already substantially increased the genetic diversity of the captive population after he was discovered to have more unique [[allele]]s than any other horse living at the time, including otherwise lost genetic material from two of the original captive founders.<ref name=":0" /> To produce the clone, frozen skin [[fibroblast]]s were thawed, and grown in [[cell culture]].<ref name=":1">{{Cite web|title=About Cloning {{!}} Revive & Restore|url=https://reviverestore.org/projects/przewalskis-horse/about-cloning/|access-date=2020-11-15|language=en-US|archive-date=30 November 2020|archive-url=https://web.archive.org/web/20201130143403/https://reviverestore.org/projects/przewalskis-horse/about-cloning/|url-status=live}}</ref> An oocyte was collected from a domestic horse, and its nucleus replaced by a nucleus collected from a cultured Przewalski's horse fibroblast. The resulting embryo was induced to begin division. It was cultured until it reached the [[blastocyst]] stage, then implanted into a domestic horse [[Surrogacy|surrogate]] mare,<ref name=":1" /> which carried the embryo to term and delivered a foal with the Przewalski horse DNA of the long-deceased stallion.

The cloned horse was named Kurt, after Dr. [[Kurt Benirschke]], a [[geneticist]] who developed the idea of cryopreserving genetic material from species considered to be endangered. His ideas led to creating the Frozen Zoo as a genetic library.<ref>{{Cite web|title=Kurt Benirschke (1924-) {{!}} The Embryo Project Encyclopedia|url=https://embryo.asu.edu/pages/kurt-benirschke-1924|access-date=2020-11-15|website=embryo.asu.edu|archive-date=30 October 2020|archive-url=https://web.archive.org/web/20201030173303/https://embryo.asu.edu/pages/kurt-benirschke-1924|url-status=live}}</ref> In 2021, Kurt was relocated to the breeding herd at the [[San Diego Zoo Safari Park]].<ref>{{cite web |last1=Beale |first1=Mel |title=Why a cloned foal born at a USA zoo is key to the survival of his endangered breed |url=https://www.yourhorse.co.uk/news/cloned-foal-key-survival-endangered-breed/ |website=Your Horse |language=en |date=10 June 2021}}</ref><ref name="SDZoo 2022">{{cite web |url= https://stories.sandiegozoo.org/2022/10/20/a-clone-and-his-mentor/ |title= A Clone and His Mentor |author= <!--Not stated--> |date= 20 October 2022 |website= sandiegozoo.org |publisher= [[San Diego Zoo]] |access-date= 29 February 2024 |archive-date= 29 February 2024 |archive-url= https://web.archive.org/web/20240229234821/https://stories.sandiegozoo.org/2022/10/20/a-clone-and-his-mentor/ |url-status= dead }}</ref> In order to integrate him into the existing herd, Kurt was partnered with a young female named Holly, a few months older than him, in order to allow him to learn the social and communication behaviors of wild Przewalski's horses. On reaching maturity at three to four years of age, Kurt is intended to become the breeder stallion for the San Diego Zoo herd to pass Kuporovic's genes into the larger captive Przewalski's horse population and thereby increase the genetic variation of the species.<ref name=":0" /><ref name="SDZoo 2022"/>

In 2023, a genetic twin of Kurt, named Ollie, was born from cloning with the help of the San Diego Zoo Global Frozen Zoo. It is the first reported case of any endangered species having more than one clone successfully produced. This individual eventually joins Kurt and Holly at the San Diego Zoo Safari Park.<ref>{{cite web|author=Black, A.|date=April 19, 2023|title=Second Przewalski horse born from cloning|url=https://www.cbs8.com/article/news/local/second-cloned-przewalski-horse/509-4c46e2f6-c583-4cd6-9b51-5065124f3e14|website=CBS News 8|access-date=April 20, 2023}}</ref><ref name="Novak et al">{{cite bioRxiv |biorxiv=10.1101/2023.12.20.572538 |title=Endangered Przewalski's horse, Equus przewalskii, cloned from historically cryopreserved cells |date= 9 January 2024 |last1=Novak |first1=Ben J. |last2=Ryder |first2=Oliver A. |last3=Houck |first3=Marlys L. |last4=Putnam |first4=Andrea S. |last5=Walker |first5=Kelcey |last6=Russell |first6=Lexie |last7=Russell |first7=Blake |last8=Walker |first8=Shawn |last9=Arenivas |first9=Sanaz Sadeghieh |last10=Aston |first10=Lauren |last11=Veneklasen |first11=Gregg |last12=Ivy |first12=Jamie A. |last13=Koepfli |first13=Klaus-Peter |last14=Rusnak |first14=Anna |last15=Simek |first15=Jaroslav |last16=Zhuk |first16=Anna |last17=Phelan |first17=Ryan }}</ref> Due to having been conceived through the transfer of a somatic cell nucleus into an egg cell obtained from a domestic horse donor, Kurt and Ollie both display the mitochondrial genome of domestic horses instead of belonging to a Przewlaski horse mithocondrial clade.<ref name="Novak et al"/> However, as [[Mitochondrial_DNA#Mitochondrial_inheritance|mitochondrial DNA is maternally inherited]], they will not pass on these domestic horse genes.