Australian megafauna

When people first arrived in Australia, they found unique plants and animals. It must have been like entering a new world. There were giant marsupials (mammals that carried their young in a pouch, such as kangaroos), giant monotremes (mammals that lay eggs, such as echidnas) and different types of birds (including emus and brolgas). There were also other giant animals that no longer exist. We call these extinct giant animals megafauna. 

The name megafauna means 'big animals', generally animals with a body mass of over 40 kilograms. Much of the time, megafauna is a general term used to describe a particular group of large land animals that evolved during the Pleistocene epoch millions of years after the dinosaurs became extinct.

Naracoorte Caves

Many megafauna fossils have been found in pitfall caves like the World Heritage-listed Naracoorte Caves on the Nullabor plain, where animals fell in through roof holes and were unable to escape. Animals became trapped in the caves at Naracoorte over a period of 500,000 years, leaving it with a rich fossil record covering more than 130 vertebrate species.

Evidence of coexistence

In June 2008 Tim Willing, while exploring rock art on the north-western coast of the Kimberley, found and recorded the image of a large striped quadruped painted in a shelter near the western shore of the Admiralty Gulf.

Extinction theories

There has been passionate debate among scientists about what caused the extinction of the megafauna, ancient giant relatives of Australia's marsupials and monotremes that died out tens of thousands of years ago. While some scientists favour natural climate change, others say that the arrival of humans drove the giant fauna to extinction either through hunting or the use of fire to alter the landscape.

Source

Around 88 large vertebrate taxa disappeared from Sahul sometime during the Pleistocene, with the majority of losses (54 taxa) clearly taking place within the last 40,000 years. The largest was the 2.8-ton browsing Diprotodon optatum, whereas the ∼100- to 130-kg marsupial lion, Thylacoleo carnifex, the world’s most specialized mammalian carnivore, and Varanus priscus, the largest lizard known, were formidable predators. Explanations for these extinctions have centered on climatic change or human activities. Here, we review the evidence and arguments for both. Human involvement in the disappearance of some species remains possible but unproven. Mounting evidence points to the loss of most species before the peopling of Sahul (circa 50–45 ka) and a significant role for climate change in the disappearance of the continent’s megafauna.

PEEL Paragraph

EVALUATE THE EVIDENCE FOR THE EXTINCTION OF MEGAFAUNA IN ANCIENT AUSTRALIA. 

Australian megafauna became extinct about 42,000 years ago at the same time that the Pleistocene epoch ended, and the people who arrived on the continent migrated from the north to the south, therefore a  combination of these two factors is the most likely cause of extinction. Evidence that supports a nuanced interaction of both people and changing climate includes different rates of extinction. This is significant because the different patterns cannot be explained by people acting as ‘super-predators’ or climate change.  Furthermore, there is a lack of reliable evidence that clearly points to either climate change or humans hunting and changing the ecosystem through fire management. Researchers often must rely on a single artefact such as a diprotodon tooth or a single site which limits the applicability of evidence to other situations. Ultimately, considering the research and evidence we have at the moment it seems as if it was a combination of both climate change and humans that led to the extinction of megafauna in Australia. 

Further Reading