A pictorial depiction of the Zanda horses running the open steppe habitat of the Tibetan Plateau. (Illustration/Yu Chen)
DHARAMSHALA, April 24: The discovery of a skeleton of an ancient three-toed horse from the Tibetan Plateau has opened new areas of study on the habitat and elevation of Tibet nearly 5 million years ago.
The fossilised horse bones were found in the Zanda Basin, in southwestern Tibet, near the Himalayas.
Researchers at the Natural History Museum of Los Angeles County have estimated that the horse is about 4.6 million years old and seemed to be from the three-toed horse genus Hipparion.
"We have an extinct horse that apparently is adapted to grasslands, these open nonwooded areas," study researcher Xiaoming Wang of the Natural History Museum of Los Angeles County told LiveScience
. "Therefore, in turn, it might have some implications about the environment that it came from."
The Tibetan plateau is the youngest and highest plateau on Earth with an average elevation exceeding 14,800 feet (4,500 meters).
Fossils of the three-toed horse, according to researchers, provide concrete evidence for studying the uplift of the plateau.
Researches have concluded that the uplift of the Tibetan Plateau has played an important factor in global climate change and strongly influenced the development of the Asian monsoon system.
With the unearthing of the horse fossil, researchers estimate that 4.6 million years ago, the Zanda Basin would have been about 13,000 feet (4,000 meters) above sea level, on par with the current elevation of that region of Tibet.
Analysing the horses’ legs, researchers say the horse was “well-adapted to open terrain [and] running fast,” concluding that the areas where the horse originally lived was above the tree lines in those days.
Researchers have drawn similarity between the ancient horse with the present day Tibetan wild ass (Tb: Kyang) which roam the Tibetan plateau.
"Those earlier horses have similar diet to the wild asses living in the area. They are grazing on grasses that are adapted to the cold," LiveScience
quoted Yang Wang, a researcher as saying. "It’s a high elevation environment, but exactly how high we don't know."
The study was published in the journal Proceedings of the National Academy of Sciences on Monday.
In September last, a paper published in the journal, Science, revealed the discovery
of Coelodonta thibetana, a newly identified species of primitive woolly rhino, dating to 3.6 million years ago on the Tibetan plateau.
The species has been regarded much older and more primitive than its Ice Age (Pleistocene) descendants in the mammoth steppes across much of Europe and Asia.
Scientists have said the discovery of the new species of wooly rhino and the three-toed horse showed that the isolated Himalayan region of Tibet served as the evolutionary cradle for Ice Age mega plant-eaters.