Back from the brink: the world's last truly wild horses had disappeared from Mongolia. Now scientists are returning the animals to their native land

Thirty-five years ago, the people of Mongolia caught what they thought was their final glimpse of a wild takh, the world's last remaining species of untamed horse. To some people, the horse became just another species on the long list of animals that are extinct (no longer living) in the wild. But to a group of scientists who refused to see extinction in the wild as a point of no return, the disappearance became a challenge: Two decades ago, they turned to zoos for help in bringing captive-bred takhi (plural for takh) back to their native land. Today takhi--the Mongolian national symbol--have returned to the vast steppes (open grasslands) that cover much of the country.

NOT AN AVERAGE HORSE

Takhi are unlike any other horses. They've never been tamed or, many people believe, ever ridden. "Some [takhi] in zoos have become tame enough to be touched. But that's about it," explains Lee Boyd, a biologist at Washburn University in Topeka, Kansas, who has studied takhi behavior.

The horses most people are familiar with are domestic homes (Equus caballus), which humans have bred over thousands of years to have a specific color, size, or temperament. Even the homes roaming freely in the mountains of the Western U.S. or on the islands along the mid-Atlantic coast aren't truly wild. They're feral, or domestic homes that have escaped to live in the wild.

Takhi (Equus fetus przewalskii) are a completely different species. Standing at just three to four feet tall, they're much shorter than domestic horses. They have a thick neck and a bristly, dark-brown mane. Takhi are also well adapted (adjusted) to a harsh life on Mongolia's steppe, where food and water are hard to find and temperatures can range from -40[degrees]C (-40[degrees]F) to 40[degrees]C (104[degrees]F). Mongolia's wild horses are also genetically different from domestic horses. Takhi have 66 chromosomes (structures in cells that carry the genetic information for an organism), while domestic horses have 64. This makes takhi unique--and irreplaceable should the species disappear completely.

HOME ON THE STEPPE

For more than 10,000 years, takhi roamed the steppe that once stretched from the Iberian Peninsula (southwest tip of Europe) to Manchuria on the east coast of China. Over centuries, the climate slowly warmed and their habitat (native environment) changed from open grassland to dense forest.

At the same time, humans began turning much of the remaining grassland into farms or grazing land for livestock. This restricted the takhi's movement and reduced their habitat even more. In the early 1900s, zoo collectors contributed to the species' decline by killing hundreds of adult takhi just so they could capture the much slower foals (young) for their exhibits. In 1969, the last takh was spotted in the wild.

CAPTIVE, BUT ALIVE

A group of Dutch scientists in the late 1970s discovered there were only 300 takhi remaining in zoos and private collections around the world. That's when they began working to return takhi to the Mongolian steppe. Why bother? "A species that survives only in captivity is actually extinct," explains Petra Kaczensky, a biologist at the Salzburg Zoo in Austria who is working on one of the takhi reintroduction programs. "For captive breeding to be more than just a museum with live exhibits, it needs to aim at the reestablishment of the species in the wild."

Before the zoo-bred takhi could be released, they had to be trained to live in the wild again. Biologists carefully selected takhi and released them into six large parks in the Netherlands and Germany. There, the horses learned to find food on their own, defend themselves against wolves, and live in family groups called harems. In 1992, researchers flew the first group of takhi to Mongolia, where the horses spent another two years getting used to the new terrain, climate, and food. Finally, the horses were released into the Hustai Nuruu National Park 90 kilometers (56 miles) southwest of Mongolia's capital, Ulaanbaatar.

GOING STRONG

Today, after several more reintroductions, nearly 209 horses roam Hustai Nuruu and another park in the far western part of Mongolia known as Gobi-B. The worldwide zoo population has "also grown to nearly 2,000 animals, which biologists hope to keep healthy so they have a reserve in case disease or another disaster kills the reintroduced animals.

Despite the reintroduction successes, takhi still aren't in the clear. Scientists are concerned that farms and grazing land near the reintroduction sites could start the cycle of decline all over again. In addition, they are trying to prevent free-roaming domesticated horses from mating with the wild horses, as this would reduce the number of pure takhi left in the world.

"People think we just put animals in the field and walk away and that's a successful reintroduction," says Randy Rieches, curator of mammals at the San Diego Wild Animal Park. But that's not the case. "It takes a lot of field scientists out there monitoring the homes and their habitat," he explains.