Przewalski's Horse Populations in Hungary

Przewalski's Horse Populations in Hungary

More than 310 of the 1,900 horses scattered around the world live in the breeding herd in Hortobágy National Park.

Photo: Courtesy István Sándor, Budapest Zoo

By Zita Makra, DVM, WEVA Regional Ambassador—Hungary

The Przewalski's horse is an endangered subspecies of wild horse that has never been domesticated. It remains the only surviving truly wild horse in the world today.

The breed is named after the Russian colonel Nikolai Przhevalsky, who first described the horses in 1878 after going on an expedition to find them at Lake Lop-nor, Kazakhstan, based on rumors of their existence. Around 1900 Carl Hagenbeck captured many Przewalski's horses and placed them in zoos.

The wild population declined in the 20th century due to a combination of factors, with the wild population in Mongolia dying out in the late 1960s; the last herd was sighted in 1967 and the last individual horse in 1969. Expeditions to Central Asia after this failed to locate any horses, and the species had been designated "extinct in the wild" for more than 30 years. At one point, just 12 individual Przewalski's horses were left in the world, only existing in European zoos. The animals in zoos eventually reproduced, ultimately resulting in the populations that exist today.

The latest genetic research has shown that the Przewalski’s horse (Equus ferus przewalskii) is most likely not the direct ancestor of the present domestic horse, but more likely a “sister taxa.” Przewalski's horse is one of three known subspecies of Equus ferus, the others being the domesticated horse Equus ferus caballus and the extinct tarpan Equus ferus ferus.

Photo: Courtesy István Sándor, Budapest Zoo

The Przewalski’s horses live in permanent family groups, so-called “harem groups.” In this system, adults form lifelong relationships and young males form bachelor groups. The Przewalski’s horse is closely related to the domestic horse, though they have a distinct difference in the number of chromosomes: Domestic horses have 64 pairs of chromosomes, while the Przewalski's horse has 66, the most of any equid species. When a Przewalski’s horse and a domestic horse breed, the offspring is born with 65 chromosomes. Those offspring are usually still viable and fertile.

The Przewalski’s horse herd in Pentezug, in Eastern Hungary, represents the largest population of wild horses in the world. More than 310 of the 1,900 horses scattered around the world live in the breeding herd in Hortobágy National Park. The Pentezug reserve is a 3,000-hectare (roughly 7,400-acre) protected wild plain. This restricted area is self-supporting and has a stable inner system enabling broad species diversity. The reserve is off-limits to tourists or visitors, and all agricultural activity is prohibited. An electric fence surrounds the wild horses, with a crossing for foxes, rabbits, deer, and wild boar. The national park’s main goals are to preserve this natural habitat, save endangered Przewalski’s horses, maintain controlled breeding of the horses, and provide a breeding program to reintroduce Przewalski’s horses to other areas.

Species breeding coordinator Dr. Waltraut Zimmermann, from Germany’s Cologne Zoo, selected the first horses to arrive in Hortobágy National Park in 1997. In this German-Hungarian common project, the Cologne Zoo covered the cost of fencing, transport, research facilities, and equipment. Horses came from zoos and animal parks all over Europe. To keep inbreeding in the new Pentezug population to a minimum, Zimmerman tried to avoid choosing horses with close relations to each other.

The imported horses arrived in small harem groups, each consisting of one adult stallion and three mares. The plan was to establish, right from the start, several smaller breeding groups in the area. However, mares ended up joining the strongest stallion and forming one large herd, while the other stallions formed a bachelor group without any mares. After several years of successful breeding and with more young stallions reaching maturity, the number of harem groups started to increase. Currently there are more than 20 harem groups of different sizes.

Photo: Courtesy István Sándor, Budapest Zoo

The breeding program has proven so successful that the managers have had to take steps to slow population growth. They have transferred several horses from the Pentezug population to other locations, such as the Budakeszi Wildlife Park, located near Budapest, Hungary, as well as a wild horse enclosure in Austria. Additionally, some mares are chosen for reintroduction into the wild in Mongolia. The Prague Zoo organizes the expensive and complicated transport of wild horses to Mongolia.

But, because of the cost of transport, only two or three horses per year are transferred for reintroduction to Mongolia. And with more than 50 foals being born at Hortobágy National Park each year, the herd managers are seeking other ways to control population growth. Some mares receive a contraceptive vaccine developed by American veterinarians to control the population of the ponies on Assateague Island, located off the coast of Maryland and Virginia. The vaccine keeps the mares from breeding for two to four years, after which they can become pregnant again. The herd managers also euthanize select horses—the weakest and least healthy—whenever the Hortobágy population grows too large. Eleven horses were euthanized at the park in 2014 because they were badly injured, very lame, and/or weak.

The most exciting and challenging part of the nature reservation work is the reintroduction of endangered species to their original habitat. Thus far, it seems to be successful in the Pentezug reservation.

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