Przewalski's horse

Przewalski's horse (Equus ferus przewalskii or Equus przewalskii), also called the takhi, Mongolian wild horse or Dzungarian horse, is a rare and endangered wild horse originally native to the steppes of Central Asia. It is named after the Russian geographer and explorer Nikolay Przhevalsky. Once extinct in the wild, since the 1990s it has been reintroduced to its native habitat in Mongolia in the Hustai National Park, Takhin Tal Nature Reserve, Khomiin Tal, and several other locales in Central Asia and Eastern Europe. Several genetic characteristics of Przewalski's horse differ from those seen in modern domestic horses, indicating neither is an ancestor of the other. For example Przewals...

Przewalski reported the horses forming troops of between five and fifteen members, consisting of a mature stallion, his mares and foals. Modern reintroduced populations similarly form family groups of one adult stallion, one to three mares, and their common offspring that stay in the family group until they are no longer dependent, usually at two or three years old. Young females join other harems, while bachelor stallions as well as old stallions who have lost their harems join bachelor groups. Family groups can join to form a herd that moves together. The patterns of their daily lives exhibit horse behavior similar to that of feral horse herds. Stallions herd, drive, and defend all members of their family, while the mares often display leadership in the family. Stallions and mares stay with their preferred partners for years. While behavioral synchronization is high among mares, stallions other than the main harem stallion are generally less stable in this respect. Home range in the wild is little studied, but estimated as 1.2–24 km2 (0.46–9.3 sq mi) in the Hustai National Park and 150–825 km2 (58–319 sq mi) in the Great Gobi B Strictly Protected Area. The ranges of harems are separated, but slightly overlapping. They have few modern predators, but one of the few is the Himalayan wolf. Horses maintain visual contact with their family and herd at all times, and have a host of ways to communicate with one another, including vocalizations, scent marking, and a wide range of visual and tactile signals. Each kick, groom, tilt of the ear, or other contact with another horse is a means of communicating. This constant communication leads to complex social behaviors among Przewalski's horses. The historical population was said to have lived in the "wildest parts of the desert" with a preference for "especially saline districts". They were observed mostly during spring and summer at natural wells, migrating to them by crossing valleys rather than by way of higher mountains.

Russia

Przewalski horse's diet consists of vegetation. In the Chernobyl exclusion zone, Przewalski's horses consume primarily grasses and forbs, including Elymus repens, Carex spp., Fabaceae, and Asteraceae. Looking at the species' diet overall, Przewalski's horses most often eat E. repens, Trifolium pratense, Vicia cracca, Poa trivialis, Dactylis glomerata, and Bromus inermis. While the horses eat a variety of different plant species, they tend to favor different species at different times of year. In the springtime, they favor Elymus repens, Corynephorus canescens, Festuca valesiaca, and Chenopodium album. In early summer, they favor Dactylis glomerata and Trifolium, and in late summer, they gravitate towards E. repens and Vicia cracca. In winter the horses eat Salix spp., Pyrus communis, Malus sylvatica, Pinus sylvestris, Rosa spp., and Alnus spp. Additionally, Przewalski's horses may dig for Festuca spp., Bromus inermis, and E. repens that grow beneath the ice and snow. Their winter diet is very similar to the winter diet of domestic horses, but differs from that revealed by isotope analysis of the historical (pre-captivity) population, which switched in winter to browsing shrubs, though the difference may be due to the extreme habitat pressure the historical population was under. In the wintertime, they eat their food more slowly than they do during other times of the year. Przewalski's horses seasonally display a set of changes collectively characteristic of physiologic adaptation to starvation, with their basal metabolic rate in winter being half what it is during springtime. This is not a direct consequence of decreased nutrient intake, but rather a programmed response to predictable seasonal dietary fluctuation.

Przewalski reported the horses forming troops of between five and fifteen members, consisting of a mature stallion, his mares and foals. Modern reintroduced populations similarly form family groups of one adult stallion, one to three mares, and their common offspring that stay in the family group until they are no longer dependent, usually at two or three years old. Young females join other harems, while bachelor stallions as well as old stallions who have lost their harems join bachelor groups. Family groups can join to form a herd that moves together. The patterns of their daily lives exhibit horse behavior similar to that of feral horse herds. Stallions herd, drive, and defend all members of their family, while the mares often display leadership in the family. Stallions and mares stay with their preferred partners for years. While behavioral synchronization is high among mares, stallions other than the main harem stallion are generally less stable in this respect. Home range in the wild is little studied, but estimated as 1.2–24 km2 (0.46–9.3 sq mi) in the Hustai National Park and 150–825 km2 (58–319 sq mi) in the Great Gobi B Strictly Protected Area. The ranges of harems are separated, but slightly overlapping. They have few modern predators, but one of the few is the Himalayan wolf. Horses maintain visual contact with their family and herd at all times, and have a host of ways to communicate with one another, including vocalizations, scent marking, and a wide range of visual and tactile signals. Each kick, groom, tilt of the ear, or other contact with another horse is a means of communicating. This constant communication leads to complex social behaviors among Przewalski's horses. The historical population was said to have lived in the "wildest parts of the desert" with a preference for "especially saline districts". They were observed mostly during spring and summer at natural wells, migrating to them by crossing valleys rather than by way of higher mountains.

Mating occurs in late spring or early summer. Mating stallions do not start looking for mating partners until the age of five. Stallions assemble groups of mares or challenge the leader of another group for dominance. Females are able to give birth at the age of three and have a gestation period of 11–12 months. Foals are able to stand about an hour after birth. The rate of infant mortality among foals is 25%, with 83.3% of these deaths resulting from leading stallion infanticide. Foals begin grazing within a few weeks but are not weaned for 8–13 months after birth. They reach sexual maturity at two years of age.

Przewalski's horse was formally described as a novel species in 1881 by Ivan Semyonovich Polyakov. The taxonomic position of Przewalski's horse remains controversial, and no consensus exists about whether it is a full species (as Equus przewalskii); a subspecies of Equus ferus, the wild horse, (as Equus ferus przewalskii in trinomial nomenclature, along with two other subspecies, the domestic horse E. f. caballus, and the extinct tarpan E. f. ferus); or even a subpopulation of the domesticated horse. The American Society of Mammalogists considers both Przewalski's horse and the tarpan to be subspecies of Equus ferus and classifies the domesticated horse as a separate species, Equus caballus.

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 genetic bottleneck made likely. By 1979, when this concerted program of population management to maximize genetic diversity was begun, there were almost four hundred horses in sixteen facilities, a number that had grown by the early 1990s to over 1,500. 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. Though poaching has taken a toll on numbers, as of 2019 the estimated population in the Chernobyl zone was over 100 individuals. 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. 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. 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. Another population is being established in the Iberian System in Spain, the first free-roaming Przewalski's horses in Western Europe. In 2024, a Colorado rancher discovered what appears to be a Przewalski's horse at a Kansas livestock auction, 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. One horse, Fiona, was euthanized following apparent organ failure, while the other's fate is unreported.

Przewalski's horse was formally described as a novel species in 1881 by Ivan Semyonovich Polyakov. The taxonomic position of Przewalski's horse remains controversial, and no consensus exists about whether it is a full species (as Equus przewalskii); a subspecies of Equus ferus, the wild horse, (as Equus ferus przewalskii in trinomial nomenclature, along with two other subspecies, the domestic horse E. f. caballus, and the extinct tarpan E. f. ferus); or even a subpopulation of the domesticated horse. The American Society of Mammalogists considers both Przewalski's horse and the tarpan to be subspecies of Equus ferus and classifies the domesticated horse as a separate species, Equus caballus.