Despite previous theories that the extinction of Australian megafauna, animals that existed during the Pleistocene period which took place around 1.8 million years ago up until their extinction, may have been the result of climate change, a new study from scientists at the University of Tasmania reveals that human hunting was the likely cause, according to Australia Network News.

The study reveals that many of Australia's prehistoric animals, including giant kangaroos and large flightless birds, were wiped out due to human acitivity approximately 40,000 years ago.

"We looked at ... the dates of when humans arrived and what the climate was doing," said James Cook, co-author of the study. "We found the climate wasn't doing anything it hadn't done before ... and there was a close link between humans and megafauna extinction."

Michael Bird, another co-author of the study, says that the time period when the megafauna disappeared coincides with the arrival of humans at the Sahul landmass, which eventually split into what is now Papua New Guinea, Australia's mainland, and Tasmania, according to the Daily Mail.

"We are not saying people came and started killing everything. But when people get involved in population dynamics, through things like hunting, taking eggs and killing juveniles, it affects things over time," Bird added.

Another study published last year supports the current hypothesis with evidence of charred animal eggs that point to their use for human consumption, although hazy carbon dating and climate records makes it difficult to put a precise date on the remains, according to SBS News.

"Today, Sahul has no native terrestrial animal larger than about 40 kilograms, but for much of the Pleistocene it supported diverse large vertebrates up to almost 3 tonnes," Cook said. "The overkill hypothesis proposes that human hunting drove these animals extinct."

The findings were published in the Feb. 10 issue of the Proceedings of the Royal Society B.