Climate shift killed Australia’s giant beasts


EXTINCTION: This file photo taken at the Australian Museum in Sydney shows Brendan Atkins, publications co-ordinator and editor at the museum, standing alongside a reconstructed model of a ‘diprotodon’, an ancient rhino-sized mega-wombat as Australian scientists unveiled the biggest-ever graveyard of Diprotodons, with the site potentially holding valuable clues on the species’ extinction. — AFP photo

SYDNEY: Gigantic animals which once roamed Australia were mostly extinct by the time humans arrived, according to a new study yesterday which suggests climate change played the key role in their demise.

For decades, debate has centred on what wiped out megafauna such as the rhinoceros-sized, wombat-like Diprotodon, the largest known lizard, and kangaroos so big that scientists are studying whether they could hop.

The study, published in the Proceedings of the National Academy of Sciences, said some species were still surviving when people arrived about 45,000 to 50,000 years ago.

But the review, led by the University of New South Wales, found that while human involvement in the disappearance of the megafauna was possible, climate change was the more likely culprit.

“There is no firm evidence whatsoever that a single human ever killed a single individual megafauna,” the study’s lead author, University of New South Wales zoologist Stephen Wroe told AFP.

“Not a thing. There is not a single kill site in Australia or (Papua) New Guinea. There’s not even the sort of tool kit that you would typically associate for hunter gatherers with killing big animals.”

Wroe said the fossil records showed that the clear majority of now extinct species of megafauna “can’t be placed within
even 50,000 years of when humans were thought to have first arrived”.

“No more than about 14, perhaps as few as eight, species were clearly here when humans made foot-fall,” he said.

Wroe said there was also mounting evidence that their extinction took place over tens, if not hundreds, of millennia during which time there was a progressive deterioration in the climate. — AFP