SYDNEY, Dec. 9 (Xinhua) -- A severe drought on the Indonesian island of Flores may have driven the extinction of the ancient "hobbits" species Homo floresiensis 61,000 years ago.
Australia's University of Wollongong (UOW) and Indonesian scientists have uncovered compelling new evidence that severe drought, caused by a changing climate, sparked one of the great mysteries in human evolution -- the vanishing of the "hobbits" of Flores, a UOW media release said Tuesday.
The study reveals the Homo floresiensis, and one of its main prey, the Stegodon florensis insularis, both of which once lived on the eastern Indonesian island of Flores, abandoned the Liang Bua cave during a prolonged period of aridity that lasted for thousands of years, it said.
Combining precise chemical records from cave stalagmites with isotopic data from fossil teeth of the Stegodon, a species of pygmy elephant, the scientists revealed an extensive drying trend beginning around 76,000 years ago.
The trend culminated in severe summer drought between 61,000 and 55,000 years ago, triggering a collapse in freshwater sources and food supply.
"Summer rainfall fell to about half of modern levels and river-bed water sources became seasonally dry, placing ecological stress on both hobbits and their prey," said Mike Gagan, honorary professor at UOW.
The remains of Homo floresiensis were first uncovered in 2003 in Liang Bua cave. The fossil type specimen, dubbed the "Hobbit" due to its tiny stature, radically challenged the prevailing theories of human evolution and dispersal across the globe, said the study published in Communications Earth & Environment.
"Competition for dwindling water and food probably forced the hobbits to abandon Liang Bua altogether," said Gert van den Berg, honorary fellow at UOW's School of Science.
The research clarifies the timeline of humans on Flores. While Homo floresiensis fossils pre-date the earliest evidence of modern humans on the island, Homo sapiens were traversing the Indonesian archipelago around the time the hobbits disappeared.
"It's possible that as the hobbits moved in search of water and prey, they encountered modern humans elsewhere on the island," Gagan said. "In that sense, climate change may have set the stage for their final disappearance." ■
