Our ancestors sounded death knell of prehistoric animals

August 12th, 2008 - 1:57 pm ICT by IANS  

Sydney, Aug 12 (IANS) Human hunting sounded the death knell of large prehistoric animals like giant kangaroos, marsupial rhinos and leopards, rather than climate change as previously believed. People who arrived in Tasmania around 41,000 years ago, when a land bridge connected the island to mainland Australia, accounted for the mass extinction of the these giant animals, known as megafauna.

Richard “Bert’ Roberts, co-leader of a study from University of Wollongong (UOW) said that scientists seem to absolve humans of any involvement in their disappearance.

However, the international study, using the latest radiocarbon and luminescence dating techniques, determined the age of the fossilised remains of the megafauna more accurately than ever before.

The results showed that some of these animals survived until at least 41,000 years ago - much later than previously thought and up to 2,000 years after the first human settlers arrived.

As climate in Tasmania was not changing dramatically at this time, the researchers argued that this is evidence of these species being driven to extinction through over-hunting by humans.

Chris Turney of the University of Exeter in Britain, co-author of the paper, said “ever since Charles Darwin’s discovery of giant ground sloth remains in South America, debate has ensued about the cause of early extinction of the world’s megafauna.

“It is sad to know that our ancestors played such a major role in the extinction of these species - and sadder still when we consider that this trend continues today.”

Now, 150 years after the publication of Darwin’s seminal work The Origin of Species, the argument for climate change being the cause of this mass extinction has been seriously undermined.

Given Tasmania’s history as an island, these findings should help to disentangle the role of humans and climate change in other island environments.

Palaeontologist and co-author, Tim Flannery of Macquarie University, said that island environments offered an excellent test of competing hypotheses.

These findings were published in the Proceedings of the National Academy of Sciences.

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