Men faced monsters in early Outback
Giant kangaroos, lizards as long as buses and three-tonne marsupials roamed Australia along with the first humans for thousands of years before being wiped out by climate change, a study has found.
Australian researchers say that the first people to have arrived on the continent about 50,000 years ago would have been confronted by huge beasts including a kangaroo twice as tall as man, six-metre goannas or lizards and the fearsome Thylacoleo, a marsupial lion. The study of bones found in Queensland’s Outback has determined that, contrary to previous theories that many species were hunted to extinction, the animals lived alongside humans for up to 20,000 years. Severe changes in the environment probably led to their doom rather than predation.
The study, published in the journal Nature Communications, tells of research on the trove of ‘‘megafauna’’ fossils discovered by the Barada Barna Aboriginal people in 2008. The authors, drawn from Australian museums and universities, describe their work as ‘‘the first reliable glimpse of the giants that roamed the Australian tropics’’.
They have so far identified at least 13 extinct species from the area described as South Walker Creek, about 1000km north of Brisbane.
Most are likely to be new species of megafauna or variations of known species. The findings range from minute fish scales to large limb bones.
Some creatures, such as the huge land-dwelling crocodiles, were previously thought to have become extinct before man arrived in Australia. ‘‘Imagine first sighting a six-metre goanna and its Komodo dragon-sized relative or bumping into a land-dwelling crocodile,’’ the authors wrote on The Conversation website.
‘‘The mammals were equally bizarre, including a buck-toothed wombat, a strange ‘bear-sloth’ marsupial and enormous kangaroos and wallabies.
‘‘With an overlap between people and megafauna of some 15,000-20,000 years, new questions arise about cohabitation. How did people live with these giants during a period of such drastic environmental change?’’
It was previously thought that Australia’s megafauna were driven to extinction by overhunting and that they were all gone soon after man arrived.
The latest research finds instead that a diverse collection of the ancient giants survived well after the first Aboriginal inhabitants had spread around the continent. Living alongside the larger mammals were species that still survive today: the emu, the red kangaroo and the saltwater crocodile, the authors said.
Extreme environmental change, not humans, was the most likely cause of extinction. The loss of water flow, intensified drying, increased burning and vegetation change created the conditions for the larger mammals’ demise.
‘‘Their extinction is coincident with major climatic and environmental deterioration both locally and regionally, including increased fire, reduction in grasslands and loss of freshwater,’’ Scott Hocknull, a palaeontologist at Queensland University and one of the study’s authors, said. ‘‘Together, these sustained changes were simply too much for the largest of Australia’s animals to cope.’’
The authors said their study showed that dramatic environmental change took a heavy toll on a species’ survival, especially for those at the top of the food chain.
They believe it has a lesson still pertinent today. ‘‘Will we heed the warnings of the past or suffer the consequences?’’ they asked.