Deep in Tibet, in a high and icy valley, the explorers came upon the first of the enigmatic creatures. They saw one, and then three of them grazing in the open forest. Soon, to their astonishment, a whole herd of the unusual horses appeared.
“They looked completely archaic, like the horses in prehistoric cave paintings,” said Michel Peissel, a French ethnologist and the expedition leader. “We thought it was just a freak, then we saw they were all alike.”
A team of French and British explorers, who have just returned here from a six-week expedition in Tibet, say they believe they found an ancient breed of horse previously unknown to scientists.
The Riwoche horse, as the explorers have named it after its home region in northeastern Tibet, is close to four feet high, about the size of a pony. Its head is triangular and has the same wedge shape as the zebra or as the vanished horses of European stone-age drawings. It has a beige coat, bristly mane, black stripe on its back and black lines on its lower legs.
The explorers and other scientists believe that the breed may provide a new piece in the puzzle of equine evolution. Although for many centuries, horses have been vital to humans in work, transport and warfare, scientists say the tale of how horses developed and diversified is far from complete.
They believe it took perhaps 50 million years for a small browsing animal, less than two feet high, named the Eohippus, to evolve and branch off into rhinos and tapirs as well as into the species that eventually developed into the zebra, ass, donkey and horse.
The modern horse is thought to be five million years old. Cave men hunted it and ate it. Only for the last 3,000 to 5,000 years has the horse been domesticated.
Steven Harrison, a geneticist at the Royal Agricultural College in Cirencestor, England, will do DNA tests on the Tibetan horses’ blood samples.
“It’s very rare to find a big mammal we did not know about,” he said. “It will be very interesting to compare the genetic markers to those of other wild horses,” he said, like Przewalski’s horse, a wild Mongolian breed first recorded about a century ago.
Dr. Ignasi Casas, a veterinarian who was a member of the expedition, said he believed the Riwoche (ree-woe-chay) breed may be a “relic population” that lived isolated from others for a very long time and thus preserved its characteristics.
“It looks very primitive and very tough,” Casas said. “Horses in the adjacent areas are very different.”
Although the animals were roaming free in the Riwoche region, Casas believes that one explanation for their archaic form is that the 17-mile-long valley where they were found is closed off on both sides by passes about 16,000 feet high.
“Horses would not roam through those passes easily because at that altitude there is no grass, no food to survive,” Casas said.
Down in the valley, which is studded with hamlets of Bon-po people, the pre-Buddhist natives of the region, farmers catch the horses with a lasso when they want to ride them or pack them, said Casas. Then they set the horses free until they are needed again.
“We could approach them to about 15 feet, then they moved,” he said. Nonetheless, the team caught some of the horses and took the blood samples and filmed them for future studies.
“There is nothing in the literature about this horse,” said Casas, who is associated with the Royal Animal Health Trust, an equine research center and clinic in Newmarket, England.
“It’s an exciting find because horses have bred and mixed and traveled all over the world, but this one so far seems unique.”
The purpose of the expedition was to observe and test the properties of the Nangchen horse, another breed, which Peissel first recorded in 1993.