Which megafauna did Indigenous Australians encounter?

There is still some debate about exactly when Indigenous Australians first made it onto the continent via a land bridge from southeast Asia. But what is clear is that, whether they arrived 45,000 or 65,000 years ago, the landscape would have been quite different – and that goes for some of the wildlife too.

Across the globe, the Late Pleistocene era (about 126,000 to 12,000 years ago) saw many “megafauna” roaming the land. An animal has to weigh over 44 kilograms to qualify for megafaunal status – for comparison, this is a little heavier than an average European wolf.

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At the end of the Pleistocene, most of these giant land animals disappeared, including the Australian megafauna. The only continent where a significant number of megafauna survived is Africa.

Among Australia’s now extinct megafauna are the largest ever marsupial Diprotodon, the giant three-metre-tall short-faced kangaroos Procoptodon, and the world’s largest ever terrestrial lizard Megalania, which reached up to seven metres in length.

Would the sunburnt continent’s first human inhabitants have seen megafauna when they arrived tens of thousands of years ago? And what would their interactions with Australia’s ancient beasts have been like?

“There were certainly some megafaunal species that were here when humans arrived,” says Professor Mike Archer from the University of New South Wales and an expert on Australian palaeontology. “These would include things like Zygomaturus trilobis, which was one of the bigger diprotodontids. Possibly Diprotodon too.

“There are sites that demonstrate well dated skeletons of Zygomaturus that are about 34,000 years old out in Willandra, NSW” Archer adds.

Other species of now extinct megafauna that may have been present on the continent when the first Indigenous Australians arrived include the “marsupial lion” Thylacoleo carnifex, Palorchestes azael known as the “marsupial tapir,” and the giant flightless bird Genyornis. This large dromornithid bird could reach over two metres tall and well over 200 kilograms and was the last member of its group in the world.

There are “conflicting views” over the interactions between these early Indigenous peoples and the megafauna of Australia.

Scientists who promote a “blitzkrieg” theory, Archer says, believe that the first Australians “encountered virtually all of the extinct Late Pleistocene animals and within 1000 years and slaughtered them all.”

“The papers that we’ve published on this demonstrate that about 85% of the Late Pleistocene extinct megafauna was in fact extinct before humans even arrived. The few that were still around when humans arrived coexisted with humans seemingly peacefully, although I don’t doubt there was some sustainable use as there is on all continents with Indigenous peoples,” Archer notes.

Archer highlights that, scavenging and possibly predation would have taken place, but not to the extent that would have led to a sudden decline in the megafauna populations.

“There is no evidence that they, in any way, negatively impacted the survival prospects for those species. Many of them that they overlapped with for 30,000 years. This hardly what you call blitzkrieg,” Archer says.

Pointing to case studies on other large island ecosystems such as New Zealand, Madagascar and even Tasmania, Archer says that the preponderance of evidence points to early Indigenous human settlers living sustainably with the megafauna in these areas before the animals went extinct.

Archer says that it was climate change that led to these extinction events. As the last Ice Age began to thaw, fluctuating global temperatures saw massive habitat changes.

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In Europe and North America, the greatest impact was felt about 12,000 years ago. “In Australia,” Archer says, “there was a critical period around 30,000 years ago. After that, there was a bit of fluctuation, but we suspect that most of the megafauna that we lost went out around that period.”

But human activity has caused extinctions in Australia – much more recently.

“The extinctions that have occurred are the ones that have occurred since Europeans arrived,” Archer says. “The way that Europeans use the land, which is inappropriate, does cause massive losses of animals. It has led already to more than 35 mammal extinctions in Australia. All of those were doing extremely well before Europeans arrived. Yet most of them were also being sustainably utilized by Aboriginal people. It’s a contrast between the Aboriginal attitude and the valuing scheme they had about native animals.

“Conservation through sustainable use is the underpinning strategy that is typical of Indigenous peoples all around the world. We need again to be reinventing, understanding, emulating the way Indigenous people have always lived with and sustained, valued and sustainably utilized wildlife,” Archer says.

During NAIDOC Week (2-9 July 2023), an annual observance in Australia that celebrates and recognises the history, cultures and achievements of Aboriginal and Torres Strait Islander peoples, Cosmos is publishing a series of articles on Australia’s First Peoples and science.