Humans may have been responsible for “megafauna” demise 46,000 years ago

June 23rd, 2009 - 2:28 pm ICT by ANI  

London, June 23 (ANI): A team of scientists has analyzed the fossil of the extinct giant kangaroo to determine that humans were responsible for the demise of “megafauna” 46,000 years ago.

There has long been dissent in the palaeontology community about the cause for extinctions worldwide after the end of the last ice age.

Central to the debate has been the demise of the Australian megafauna, including animals such as marsupial lions, hippopotamus-sized wombats and the 2m-tall giant kangaroo Procoptodon goliah.

Last year, researchers dated fossils from Tasmania with the best precision yet, finding that many species survived more than 2,000 years after the arrival of humans.

Now, according to a report by BBC News, the researchers concluded that the megafauna eventually met their end due to hunting.

Researchers from Australia and the US have combined radiocarbon dating with a so-called microwear analysis of the teeth of P. goliah to determine what it ate and drank.

Different sources of water and food leave trace amounts of particular types, or isotopes, of hydrogen and carbon atoms, which are deposited in the teeth like a recorded diet.

Additionally, tiny patterns of wear give clues about the type of food a given creature chewed.

The team concluded that the giant kangaroos fed mainly on saltbush shrubs.

Because fire does not propagate well among saltbush, and because it thrives in a dry, arid climate, the case supporting two of the three potential causes for extinction was weakened.

Evidence suggests therefore that the P. goliah was hunted to extinction.

According to co-author of the study, Larisa DeSantis of the University of Florida, “What’s really exciting is that this is one of the first instances where we’ve been able to use both isotopes and the microwear method to identify this very unique diet.”

Dr DeSantis said that she was pursuing a similar analysis of other megafauna fossils in other regions of Australia.

“This study neatly ties up several loose threads in the long-running extinction debate,” said Richard Roberts of the University of Wollongong in Australia.

“By independently reaching the same conclusion for two very different environments - the mountainous rainforests of Tasmania and the dry rangelands of inland Australia - the mystery is no longer whether humans were ultimately responsible for the disappearance of the giant marsupials, but how they did it,” he added. (ANI)

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