Humans caused extinction of Genyornis newtoni in Australia
Researchers have found the first direct evidence that humans played a substantial role in the extinction of a giant bird species which inhabited Australia about 50,000 years ago.More than 85 per cent of Australia’s large mammals, birds and reptiles disappeared after people arrived.The study published in the journal Nature Communications is the first to provide direct evidence early humans preyed on the remarkable large animals that once thrived in Australia, but disappeared after people arrived, University of Colorado geological sciences Professor Gifford Miller said.At two-metres tall and weighing 225 kilograms, the Genyornis, a huge flightless bird that once roamed prehistoric Australia was a mighty presence in the mammal world.The Genyornis lived 1.8 million to 40,000 years ago.They were flightless bird, taller and heavier than the modern-day emu and co-existed with humans for 15,000 years.It was the last of the large “thunder birds” local to Australia.Genyornis populations declined and became extinct over a short period of time. The bird lived in the dry grasslands and woodlands of southern and eastern Australia.Its fossils have been found in Mt Gambier, South Australia especially on the surface of the dry Lake Callabonna and New South Wales and footprints found in dunes on southern Victoria.The bones of a number of birds have been found in one place, suggesting they could have lived in flocks.Genyornis newtoni, was nearly 7 feet tall and appears to have lived in much of Australia prior to the establishment of humans on the continent 50,000 years ago, said Gifford Miller. Researchers found reliable proof that humans were preying on now-extinct Australian Megafauna.
The researchers analyzed burned Genyornis eggshell fragments some only partially blackened discovered at more than 200 sites.The eggs were the size of a rockmelon, weighing about 1.5 kilograms.”We conclude the only explanation is that humans harvested the giant eggs, built a fire and cooked them, which would not blacken them, then discarded the fragments in and around their fire as they ate the contents,” Professor Miller said.”Wild or natural fires could not produce such patterns.”We have no direct evidence that humans hunted the adults, but loss of eggs certainly reduced reproductive success.”Another line of evidence for early human predation on Genyornis eggs is the presence of ancient, burned eggshells of emus flightless birds weighing only about 100 pounds and which still exists in Australia in the sand dunes.Emu eggshells exhibiting burn patterns similar to Genyornis eggshells signalled that they were most likely scorched after humans arrived in Australia, Miller said.The extinct mega fauna included a 1,000-pound kangaroo, a two-ton wombat, a 25 feet long lizard, a 300-pound marsupial lion and a Volkswagen Beetle sized tortoise.Scientists are not sure precisely when humans arrived in Australia but they do know that the continent’s earliest inhabitants landed on Australia’s northern coast after a several hundred mile raft journey from Indonesia, and that by about 47,000 years ago they had scattered across the continent.