A 3.6 million-year-old fossil of the previously unknown woolly rhinoceros was discovered high on the Tibetan Plateau, indicating that the foothills of the Himalaya may have been a testing ground where large mammals developed their adaptations to a cold climate well before the Ice Age began.

Paleontologists from the Natural History Museum of Los Angeles County and the Chinese Academy of Science found the rhino's complete skull and lower jaw in 2007. They argue in a paper to be published Friday in the journal Science that the mammal adapted to the global cooling before it happened.

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.

Essentially, they found that the woolly rhino developed in the snowy Tibetan highlands while the rest of earth was much warmer. During that time, the animal developed special adaptations, including a flat shovel-like horn used to sweep away snow and find vegetation.

The team estimates that the rhino was roughly the size of today's Indian and black rhinos, but since the fossils did not include hair, paleontologists can only speculate about how woolly it might have been.

They suspect that once the Ice Age set in 2.6 million years ago, the animal then spread to northern Asia and Europe.

Not only did the team find the woolly rhino, but they also uncovered an extinct species of three-toed horse, Tibetan bharal (also known as blue sheep) and nearly 25 other kinds of mammals.

Because paleontologists have done very little work in extreme, cold regions, Xiaoming Wang, from the Natural History Museum of Los Angeles County, claims that this is the final frontier.

Cold places, such as Tibet, the Arctic, and Antarctic, are where the most unexpected discoveries will be made in the future. Wang told the Associated Foreign Press.

Wang and his colleagues noted that fossil locations of three later woolly rhino species fit the pattern of ancestry that diversified down out of the plateau.

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 complete findings of the study will be released Friday in the journal Science.