The Prezwalski’s horse is an endangered equid native to the steppes of Central Asia. Named after the Russian explorer Nikolai Przewalski, who first described them in the late 19th century, these horses have a robust build, a thick, upright mane, and a dun coat with dark legs.

Recognized as the last surviving wild horse, Przewalski’s horses are genetically distinct from their domesticated relatives. These primitive horses have 66 chromosomes, two more than domestic horses.

While the lineages of modern domesticated horses and Przewalski’s horses diverged before domestication, recent research has sparked a debate over the true ‘wild’ status of the Przewalski’s bloodline.

Hunting, habitat loss, and capture have led to the extinction of the wild population. Today, captive breeding programs aim to preserve this ancient equid and reintroduce Przewalski’s herds to their native habitat.

This article will discuss the history, characteristics, and conservation of Przewalski’s horses. Keep reading to learn what makes these horses different from domestic breeds and the importance of conserving their unique lineage.

Przewalski’s Horse History

Throughout history, Przewalski’s horses remained wild, even as their domesticated counterparts spread across the globe and transformed human civilizations.

These rare horses roamed the earth for millennia, but were relatively unknown until their first formal scientific description in the 19th century. Today, Prezwalski’s horses are classified as critically endangered, representing an important conservation priority for humankind.

Preserving this species is especially important because they are considered by many to be the last remaining type of wild horse in existence. The “wild” Mustangs and Brumbies of North America and Australia actually descend from feral domestic horses, and are not truly wild.

Taxonomy

These primitive horses get their name from the Russian colonel and explorer Nikolai Przhevalsky, whose last name is pronounced “sheh-VAHL-skee.”

In 1881, Western scientists used the description and specimens provided by Przhevalsky to classify the wild horses he observed near the modern Chinese-Mongolian border. They named the species Equus przewalskii based on the Polish spelling of Przhevalsky’s name. [1] Today, depending on the source, the main variants of the name we see are Przhevalski, Przewalski, Prejevalsky and Prjevalsky.

The American Society of Mammalogists classifies the Przewalski’s horse as a subspecies of Equus ferus, the scientific name for undomesticated horses. In trinomial nomenclature, they are referred to as Equus ferus przewalskii.

In Mongolia, Przewalski’s horses are known as takhi, a name reflecting their revered status in the region’s culture and ecosystem.

Evolution

Research suggests domesticated horses and Prezwalski’s horses share a common ancestor. [2] DNA analysis from ancient horse bones and whole genome sequencing indicates these two groups diverged between 38,000 – 72,000 years ago, with later genomic studies estimating that this divergence occurred 45,000 years ago. [2][3]

The first signs of horse domestication trace back to around 3500 BC, with archaeological findings at an ancient Botai settlement in what is now northern Kazakhstan. These findings include evidence of horse harnessing, milking, and corralling. [4]

Intriguingly, a genomic study conducted in 2018 discovered that ancient Botai horses shared DNA markers with the modern Przewalski’s lineage, while domestic breeds only had minimal (about 2.7%) Botai-related ancestry. [5] These results suggest Przewalski’s horses may descend from horses once domesticated by the Botai people.

If the Botai people had indeed briefly domesticated the ancestors of Przewalski’s horses, this means that a truly wild horse lineage no longer exists.

However, one study provided a different perspective on the domestication status Botai horses. It suggested that the dental wear found in horse remains was likely caused by natural factors, not by bridle equipment. This discovery implies that the Botai people might have used Przewalski’s horses primarily for consumption, rather than for riding or as pulling animals. [6]

Range and Habitat

Archeological remains suggest horses from the Przewalski’s lineage lived throughout Central Asia between the 5th and 3rd millennia BC. [7] These horses remained elusive, only appearing sporadically in the historical record.

The Buddhist Monk Bodowa wrote about them in the 9th century AD. Ghengis Khan reportedly encountered wild horses during his conquest of Mongolia in the 13th century. [8]

The Scottish doctor John Bell claimed he saw these wild horses in present-day Siberia in the early 18th century. By their first scientific characterization, wild Przewalski’s horses only lived in the Dzungarian Basin of the Gobi Desert. [8]

The wild animal merchant Carl Hagenbeck captured Przewalski’s horses in the Gobi to transport them back to Europe. The last recorded wild Przewalski’s horses inhabited this region until the late 1960s. [8]

Research suggests hunting and habitat loss from agricultural grazing drove Przewalski’s off their natural habitat on the steppe and into the inhospitable desert environment. [8]

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Przewalski’s Horse Characteristics

Przewalski’s horses retained more wild and primitive traits than their domestic cousins.

The Prezwalski’s horse’s unique genetic origin is evident in their physical appearance and behaviour. While selective breeding influenced traits found in modern domestic breeds, natural selection is responsible for the evolution of Przewalski’s horses.

Appearance

Przewalski’s horses have stockier builds and shorter legs than domestic horses. They typically stand between 12 and 14 hands tall and weigh between 550 to 800 pounds.

These horses also have a large head and thick neck. Their manes are erect with no forelock. Primitive markings in Przewalski’s horses include a dark dorsal stripe and leg stripes.

Most Przewalski’s horses have dun coats with dark manes, tails, and lower legs. The muzzle, flanks, and belly are pale. These pale areas are called pangarè, or mealy, markings.

Prezwalski’s horses have longer hooves than domestic horses, with significantly thicker soles. Firmer hooves and thicker soles are advantageous for hoof integrity. Studies have also identified seasonal differences in hoof horn firmness in these equines. [9]

Genetics

The entirety of the current Przewalski’s horse population descends from twelve wild-caught horses. Genetic studies identified domestic alleles in Przewalski’s horses resulting from interbreeding in early captive breeding programs. [3]

This small founding population created a genetic bottleneck, increasing inbreeding and reducing genetic diversity in Prezwalski’s horses. [3]

Hybrids

All domestic horses (Equus ferus caballus) have 64 chromosomes carrying their genetic material. Instead, Przewalski’s horses have 66 chromosomes. When Przewalski’s horses mate with domestic horses, they produce hybrids with 65 chromosomes. [10]

Unlike most equid hybrids with an odd number of chromosomes, these hybrids are fertile. Research suggests chromosome differences between Przewalski’s and domestic horses don’t disrupt sex cell production. [11]

Social Structure

Przewalski’s horses went extinct in the wild before scientists could study their natural social structure and behaviour.

Studies in captive and reintroduced Przewalski’s horses found their social structure resembles feral horses. They live in two types of highly socialized groups: [12]

  • Harems: Breeding units with one stallion, mares, and foals
  • Bachelor groups: Stallions living without mares

Behaviour

In captivity, research shows that male Przewalski’s horses are more active than females. Research suggests males devote more time to defense and acquiring mares in the wild. Mares prioritize foraging to get the energy needed for pregnancy and lactation. [12]

Time budget studies found that all Przewalski’s horses spend most of their time grazing. They have similar social communication and behaviours to horses. Aggressive behaviour within social groups is rare, but the frequency of aggressions increases with proximity. [13]

Przewalski’s horses are wild animals and cannot be handled like domesticated horses. This species is not accustomed to close human contact, and caretakers typically limit their interactions with these horses to reduce stress and avoid altering their natural lifestyle.

In managing captive Przewalski’s horses, professionals use specialized techniques that don’t require intense handling to complete husbandry work. For example, zoo keepers may train a Przewalski’s horse to place their hoof on a block for trimming without being haltered.

This method not only facilitates essential care but also helps to preserve the normal wild behaviour of Przewalski’s horses.

Przewalski’s Horse Diet

Like domestic horses, Przewalski’s horses evolved to graze constantly on roughage. In the wild, horses spend between 60 – 70% of their time foraging a variety of grasses and plants available in their natural habitat. [14]

However, research into the dietary habits of Przewalski’s horses before they went extinct in the wild reveals an interesting adaptation: these horses shifted to a mixed browsing and grazing diet during the winter when grass was sparse. [15]

Browsing refers to eating parts of woody plants and shrubs, such as leaves, tender shoots, and twigs. This dietary flexibility helped them survive in environments where their preferred food source became limited due to seasonal changes.

Human activities further influenced these dietary habits. Historically, humans often competed with wild horses for pasture lands, pushing horses away from their traditional grazing areas. This displacement likely played a role in their need to adapt to different food sources. [15]

Interestingly, reintroduced Przewalski’s horses only consume grass and do not exhibit browsing behaviours.

Przewalski’s Horse Conservation

A concerted effort to restore genetic diversity in Przewalski’s horses and preserve this endangered equid began in the 1970s. An exchange program helped reduce inbreeding, and the population of Przewalski’s horses rapidly grew.

Population

The demand for Przewalski’s horses in Western countries for captive breeding programs played a role in their extinction in the wild. European collectors trafficked dozens of foals to the West before 1930. [12]

After World War II, only 31 Przewalski’s horses remained alive in western zoos and animal parks. Only nine of these horses could breed. [12]

The last of the wild Przewalski’s horses were captured in 1947. Scientists declared Przewalski’s horses extinct in the wild when expeditions after 1969 failed to locate any horses. [12]

Today, the global population of Przewalski’s horses is estimated at 2,500, with 900 horses living in zoos and wildlife parks in Europe. Over 120 Przewalski’s horses live in captive breeding programs in North America. [16]

Thanks to conservation efforts, hundreds of Przewalski’s horses recently returned to the wild at reintroduction sites throughout Central Asia. [16]

Captive Breeding

Captive breeding programs saved Przewalski’s horses from extinction, yet the conditions of captivity and the issue of limited genetic diversity present challenges to maintaining a healthy population. Modern reproductive technologies are helping to overcome some of these challenges.

Health Problems in Captivity

Several common health problems in domesticated horses can also affect captive Przewalski’s horses, such as laminitis. [17]

Stress from poor conditions in captivity can adversely affect growth, disease resistance, and reproduction in Przewalski’s horses. [12] To maintain a healthy captive herd, enclosures should:

  • Mimic the Przewalski’s horse’s natural habitat
  • Enable normal feeding patterns
  • Provide adequate space to limit aggressive behavior

Reproduction

Captive populations of Przewalski’s horses have a low foaling rate. Research suggests a lack of gene diversity may reduce fertility in Przewalski’s mares. [18]

Conservation programs use advanced reproductive techniques developed for domestic horses to increase breeding success and genetic variability in Przewalski’s horses. The first Przewalski’s horse foal produced by artificial insemination was born in 2013.

In 2020, scientists used a cryopreserved cell line from a deceased stallion to produce the first cloned Przewalski’s horse. A second clone from the same living cell line was born in 2023. Domesticated surrogate mares birthed and raised both foals.

Cloning can help revive lost genetic diversity in endangered species, which supports resilience in reintroduced populations.

Reintroduction

Reintroduction programs aim to reestablish a wild population of Przewalski’s horses in their native habitat.

The European Conservation Project created semi-reserves in Europe to prepare Przewalski’s horses for reintroduction. A population of over 100 free-roaming Przewalski’s horses also inhabits the Chernobyl exclusion zone. [19]

Extensive research on the free-ranging population at Hortobagy National Park in Hungary helped improve conservation and reintroduction efforts in China, Mongolia, and Russia. [16]

The Przewalski’s Horse Reintroduction Project of China began in 1985. Cooperations between captive breeding programs and Mongolian scientists have enabled the successful reintroduction of Przewalski’s to Mongolia since 1986. [12]

Mortality in the Wild

The success of captive breeding programs in producing healthy Przewalski’s horses plays a key role in lowering mortality rates among these horses reintroduced to the wild.

Extreme weather and predation are significant concerns for free-ranging wild horses. Wolves are natural predators of Przewalski’s horses in their native habitat.

Common equine infectious diseases can weaken free-ranging horses and make them easy targets for predators. Studies of reintroduced Przewalski’s horses identified strangles lesions in a herd with several deaths linked to wolf predation. [20]

Other causes of death in reintroduced Przewalski’s horses identified in the study include: [20]

One study reported a mortality rate of 26.6% in a free-roaming Przewalski’s horse population during a year with extreme cold weather and heavy snowfall. [16]

Shifting Human Attitudes

Historically, human activities posed a greater threat to wild horse populations than natural predators like wolves. However, shifts in local attitudes towards wild horses have enabled reintroduced populations to thrive.

Farmers once viewed wild horses as unwelcome pasture competition for their domesticated livestock. They drove the horses away from the steppe and hunted them to feed their families. [15]

Today, Przwalski’s horses are legally protected in Mongolia. Hunting wild horses has been prohibited since 1930 and these horses are now considered a national flagship animal.

Such protections have enabled reintroduced herds to share the limited pastures of the Gobi Desert with local communities and their livestock. This access to grazing lands is vital for the survival of wild Przewalski’s horse populations.

The combined preservation efforts of local communities and innovative scientists helped Przewalski’s horses rebound from the brink of extinction and return to the wild. With continued collaboration, these last surviving wild horse have a promising future.

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References

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  2. Orlando, L. et al. Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse. Nature. 2013. View Summary
  3. Sarkissian, C. et al. Evolutionary Genomics and Conservation of the Endangered Przewalski’s Horse. Curr Biol. 2015. View Summary
  4. Outram, A. et al. The Earliest Horse Harnessing and Milking. Science. 2009. View Summary
  5. Gauntz, C. et al. Ancient genomes revisit the ancestry of domestic and Przewalski’s horses. Science. 2018.View Summary
  6. Taylor, W. et al. Rethinking the evidence for early horse domestication at Botai. Sci Rep. 2021. View Summary
  7. Librado, P. et al. The origins and spread of domestic horses from the Western Eurasian steppes. Nature. 2021. View Summary
  8. Kaczensky, P. et al. Stable isotopes reveal diet shift from pre-extinction to reintroduced Przewalski’s horses. Sci Rep. 2017. View Summary
  9. Pafon-Zugal, B. et al. History of the Przewalski’s horse (Equus Przewalskii) and morphological examination of seasonal changes of the hoof in Przewalski’s and feral horses. Pferdeheilkunde. 2013.
  10. Benirschke, K. et al. Chromosome Complement: Differences between Equus caballus and Equus przewalskii, Poliakoff. Science. 1965.View Summary
  11. Lau, A. et al. Horse Domestication and Conservation Genetics of Przewalski’s Horse Inferred from Sex Chromosomal and Autosomal Sequences. Mol Biol Evol. 2009.View Summary
  12. Turghan, M. et al. An Update on Status and Conservation of the Przewalski’s Horse (Equus ferus przewalskii): Captive Breeding and Reintroduction Projects. Animals. 2022.
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  14. Boyd, L. The behaviour of Przewalski’s horses and its importance to their management. Applied Animal Behaviour Science. 1991.
  15. Kaczensky, P. et al. Stable isotopes reveal diet shift from pre-extinction to reintroduced Przewalski’s horses. Scient Rep. 2017.
  16. Kerekes, V. et al. Trends in demography, genetics, and social structure of Przewalski’s horses in the Hortobagy National Park, Hungary over the last 22 years. Glob Ecol Conserv. 2021.
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  18. Collins, W. et al. Abnormal Reproductive Patterns in Przewalski’s Mares Are Associated with a Loss in Gene Diversity. Biol Reprod. 2012.
  19. Slivinska, K. et al. The Effects of Seasonality and Group Size on Fecal Egg Counts in Wild Przewalski’s Horses ( Equus Ferus Przewalskii, Poljakov, 1881) in The Chernobyl Exclusion Zone, Ukraine During 2014 – 2018. Helminthologia. 2020. View Summary
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