China science

Prehistoric elephant fossils in China point to Gobi Desert, not Africa, as birthplace of earth’s biggest land animals

Dating analysis of stegodon remains in western China suggests the Gobi was once a lush garden with a hospitable climate completely different from that of today

PUBLISHED : Wednesday, 06 January, 2016, 8:00am
UPDATED : Monday, 12 June, 2017, 12:53pm

Fossils of stegodon, one of the largest prehistoric members of the Elephantidae family, found in China’s western Gansu province are officially the oldest on record, according to a new study by local palaeontologists.

This discovery has helped shore up the theory that the arid and unforgiving Gobi Desert, which stretches into this region, used to be a lush garden replete with a comfortable climate that once played home to the largest animals to walk the earth in the wake of the dinosaurs.

In recent years Chinese researchers have found a number of stegodon fossils in Xingjiawan village at the northwestern boundary of Lanzhou Basin. Lanzhou is the capital of Gansu.

But recent analysis shows they could be up to 11 million years old, according to a paper the Chinese team published in the latest issue of the journal Earth and Planetary Science Letters.

Prior to this, the earliest stegodon fossil was believed to be located in Kenya. Scientists claim it is about 7 million years old.

“These [Chinese] fossils are much older than those found in Africa, which some people argue to be the birthplace of stegodons,” said Dr Ao Hong, lead scientist of the study who work at the Chinese Academy of Sciences’ Institute of Earth Environment in Xian, Shaanxi province.

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Stegodon was a massive elephant that became extinct about 12,000 years ago. It had tusks as long as three metres and towered up to four metres in height, according to some estimates, making it bigger than its more famous cousin, the woolly mammoth.

The first mammal bearing any resemblance to a primitive elephant is believed to have turned up about 5 million years after the last dinosaurs disappeared.

“Considering that most of the world’s stegodon fossils have come from China, we believe these giant elephants originated in Gansu before spreading elsewhere,” Ao added.

About 8 million years ago, the stegodons in Gansu may have experienced a population boom that forced some to embark on an epic journey westward.

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Their migratory route would most likely have passed to the southern tip of Tibetan plateau, crossing the northern part of India and the Middle East, and entering Africa via Egypt, according to a map produced by Ao and his colleagues.

The rise and spread of the sStegodon “empire” suggests that the earth’s climate was completely different millions of years ago from how it is today, the researchers claimed.

The Gobi Desert - or at least the part of it inside current Chinese borders - would have enjoyed a warm and humid climate with a verdant landscape filled with huge forests and vast grassland, they said.

The flourishing vegetation would have sustained massive mammals, including the hornless paraceratherium, an ancestor of the modern rhinoceros. This is believed to have been the largest land mammal with a height of over six metres and a weight of 20 tonness.

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“We’ve found an enormous amount of mammalian fossils in Gansu. It would have served as a paradise full of bounteous life until recent times,” Ao said.

As temperatures in the region plummeted due to global cooling and the rise of the Tibetan plateau, which blocked rainfall from the Indian ocean, large mammals in western China were significantly reduced in numbers and eventually hunted to extinction globally by man.

Scientists believe that studying the origins and migratory routes of large prehistoric animals could provide clues about the history of early humans, who may have followed similar routes in their quest to survive and find nourishment.