Australia's megafauna likely went extinct due to humans rather than climate change, new research published in the Proceedings of the Royal Society B has found.
A 16-strong team, including one Queensland scientist, meticulously sifted through a broad range of data and found human predation was the likely factor behind the extinction of Australia's megafauna, including the wombat-like diprotodon, the flightless bird genyronis and the giant kangaroo procoptodon. 
The finding comes in direct contrast to the existing theory that found megafauna extinction was most likely due to climate change and not the introduction of humans to the continent.
James Cook University professor Michael Bird said the team's multidisciplinary effort, which included ecologists, archeologists, geologists, paleontologists and climate scientists, ensured quality control on every piece of available data studied.
"We took a systematic approach to it. Is it a date on a bone or is it a date on sediment around the bone and we categorised things in terms of quality," he said.
"Dates that passed the tests were included in the paper and those that didn't were chucked out. We then matched the physical evidence with known climate records from the period and the history of human movement into the continent."
Data analysis determined when megafauna went extinct, which Professor Baird said was found to have been between 45,000 to 50,000 years ago, and whether that overlapped with a climate shift and/or human arrival on the Sahul landmass, an "unbroken" continent that is now New Guinea, the Australian mainland and Tasmania.
Professor Baird said the change in climate "really kicked into gear" from 30,000 to 20,000 years ago and was unlikely to have been the main factor behind the extinction of megafauna, given the "very short geological period" and the varied climate across the landmass.
"Megafauna had lived through several previous ice ages without any problems, there is nothing exceptional about the last cycle compared to previous cycles over the last 2 million years," Professor Baird said.
"It might have had some small impact, but the evidence points strongly to human impact as the cause of extinction for these megafauna over the period of thousands of years."
Professor Baird disagreed with the notion that humans came and "wiped everything out" instantly and said he thought it was a "more gradual process".
"These animals were big and slow to produce, if you simply hunted their offspring then there has been work to suggest that over time you would lead to these animals becoming extinct," he said.
"I don't think we know definitively at this point, it is likely to be a number of factors, but it is clear that human predation was likely to be the primary driver behind extinction."
Professor Baird was adamant to point out that this was not about accusing indigenous Australians of being responsible for megafauna extinction, and said it was simply a human trait.
"This isn't about indigenous Australians, what we are saying is that humans do exploit the environments when they arrive to the extent that they can," he said.
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