Giant animals from down under, including a 450 kilogram kangaroo and wombat weighing almost two tonnes, may have been driven to extinction by early Australians, new research suggests.
Other members of the continent's lost megafauna include a seven-metre long lizard, a 135kg marsupial lion and a tortoise the size of a Volkswagen car.
But it was a two-metre tall flightless bird, Genyornis, that has led experts to the conclusion that people may be implicated in their disappearance.
The huge bird lived in much of Australia before the arrival of humans around 50,000 years ago.
Now scientists have uncovered evidence that early humans were collecting, cooking and eating Genyornis eggs.
Burned eggshell fragments were found at more than 200 sites right across Australia.
Lead researcher Professor Gifford Miller, from the University of Colorado at Boulder, US, said: "We consider this the first and only secure evidence that humans were directly preying on now-extinct Australian megafauna."
Different dating techniques showed that the blackened fragments were between 44,000 and 54,000 years old, and probably no younger than 47,000 years.
Chemical analysis suggested a localised heat source, consistent with deliberately-lit human fires rather than wild fires. Many of the burned shell pieces were found in tight clusters less than 10 feet across, the scientists reported in the journal Nature Communications.
"We argue that the conditions are consistent with early humans harvesting Genyornis eggs, cooking them over fires, and then randomly discarding the eggshell fragments in and around their cooking fires."
More than 85 per cent of Australia's mammals, birds and reptiles weighing over 50kg vanished shortly after the arrival of the first humans, who are believed to have travelled from Indonesian islands to the continent's northern coast on rafts.
The fate of Genyornis may have been shared by other animals preyed upon by the early settlers, the scientists believe.
Climate change has also been proposed as the main factor responsible for the loss of prehistoric megafauna, both in Australia and other continents.
