Dec. 26, 2006 — Australia's giant prehistoric animals, including 10-foot-tall kangaroos and wombat-like creatures as big as a rhinoceros, were likely wiped out by aboriginal settlers, not climate change, a researcher said Tuesday.
The question of what killed Australia's so-called megafauna during the last Ice Age divides paleontologists.
The most popular theories are that climate change drove the giants to extinction more than 40,000 years ago or that Aborigines, who arrived in Australia as far back as 60,000 years ago, were responsible because of overhunting or burning the vegetation upon which the creatures fed.
But new fossil evidence from the Naracoorte Caves region of South Australia state ruled out climate change as the cause, according an article published in the latest edition of the Geological Society of America's monthly journal, Geology.
"If it wasn't climate, then it had to be humans," the article's author, Flinders University paleontologist Gavin Prideaux, said.
"The real issue now is trying to resolve whether it was hunting or whether it was landscape destruction through burning ... and a bit of both is more likely," he added.
Prideaux headed an Australian research team that recorded rainfall in the Naracoorte region over 500,000 years by examining stalagmites in the caves and studying sediments.
Fossilized remains of animals that had fallen into the limestone cave system over that time — including 20 species of extinct kangaroos, marsupial lions and hippopotamus-like marsupials — were dated using two independent methods: optically stimulated luminescence at Australia's University of Wollongong and uranium-series dating at the University of Melbourne.
"Although populations fluctuated locally in concert with cyclical climatic changes — with larger species favored in wetter times — most, if not all of them survived even the driest times. Then humans arrived," Prideaux said in a statement.
