After its long survival for 3.7 million years, the fossil of a species of woolly rhinoceros finally saw the light of day as it was uncovered in Tibet's Zanda Basin, a hotspot where scientists expect for most unexpected discoveries to come. 

The woolly rhino's fossil was discovered on the Tibetan Plateau in 2007 by paleontologists from the Natural History Museum of Los Angeles County and the Chinese Academy of Science.

The complete 3-foot-long skull and lower jaw, along with a neck vertibra were uncovered in southwestern Tibet.



Digital composite photo of the skull and lower jaw of the woolly rhino. Courtesy of Xiaoming Wang



Based on the new fossils, they argue that some mega-herbivores first evolved in Tibetan foothills of the Himalayas, and then migrated to other regions. The fossil is believed to be the oldest sample of its kind ever discovered.

Around 1 million years before the Ice Age when the known woolly rhinos roamed around, the newly discovered wooly rhinoceros lived in the Himalayas utilizing its large body, long hair and snow-sweeping structures to adapt a cold environment, according to researchers.

The cold winters in high Tibet served as a habituation ground for the mega-herbivores, which became pre-adapted for the Ice Age, successfully expanding to the Eurasian mammoth steppe, researchers said.

Equipped with a flat shovel-like horn, which it would have used to sweep away snow and find vegetation, the rhino, scientists estimate, was roughly the size of today's Indian and black rhinos. But since the fossils did not include hair, paleontologists can only guess how woolly it might have been.

The fossil is quite well preserved - just a little crushed, so not quite in the original shape; but the complete skull and lower jaw are preserved, Xiaoming Wang from the Natural History Museum of Los Angeles County told BBC News.

While scientists have thought it a reasonable idea that some mammals adapted to the global cooling well before it happened, Wang and his colleagues were able to provide proof with their finds from the Zanda Basin, which sits 3,700 to 4,500 meters above sea level and is surrounded by higher peaks.

It just happens to have the right environment to basically let animals acclimate themselves and be ready for the Ice Age cold, Wang added.

The rhino, dubbed as Coelodonta thibetan, also had teeth with high crowns, which could have made it easy for it to handle tough and high-altitude vegetation. Scientists suspect that the giant spread to northern Asia and Europe after the Ice Age set in 2.6 million years ago.



(Photo: Julie Naylor) An artist's reconstruction of a newly discovered species of Tibetan woolly rhino with a flattened horn.



The extinction of Ice Age giants such as woolly mammoths and rhinos, giant sloths, and saber-tooth cats has been widely studied, but much less is known about where these giants came from, the researchers said in a statement. The Tibetan Plateau may have been another cradle of the Ice Age giants.

The findings of the study, released on Friday in the journal Science, also included vanished species of three-toed horse, Tibetan bharal (also known as blue sheep) and almost 25 other kinds of mammals. Scientists expect cold places like Tibet, the Arctic and Antarctic as hotspots where the most unexpected discoveries will be made in the future.