London, January 5 (ANI): Contrary to the suggestion that modern koalas are dwarf descendants of prehistoric giant koalas that got extinct about 50,000 years ago, an Australian palaeontologist has established that the two species lived side by side.
University of Queensland researcher Gilbert Price, who used improved dating techniques to analyse fossils of both types of koala, says that the two species co-existed in Australian trees for hundreds of thousands of years.
He also says that this finding may be helpful in understanding why Australia's "megafauna" disappeared.
"The big question is why one koala species survived past 50,000 years ago and the other didn't make it," the Independent quoted him as telling the Australian Broadcasting Corporation.
Scientists have been debating the causes of the Australian megafauna's extinction for decades, with some attributing it to climate-induced changes in habitat and food supply, while others blaming the hunting by humans of larger animals.
Both arguments have to date been supported by using the "dwarfing" hypothesis, based on similarities between extinct megafauna and smaller, modern animals.
However, publishing his conclusions in the Quaternary Science Reviews journal, Dr. Price has cast doubt on the hypothesis.
His research not only reignites debate, but may also help conservationists to save the modern koala-who are at risk through loss of habitat, and due to high carbon dioxide levels in atmosphere that are reducing nutrients in eucalyptus leaves, their sole food source.
Dr Price, from the university's Centre for Microscopy and Microanalysis, said: "It's fascinating that up until fairly recently, in geological terms, we did have two types of koala kicking around. The fossil records do suggest that they lived in the same place at the same time. Perhaps there is something about their sizes that allowed them to fill a slightly different ecological niche."
He has revealed, while modern koalas weigh about 10kg, the giant species was two to three times heavier.
According to Dr Price, there were clear differences in their appearances.
He admitted that his research left questions unanswered about the koala's evolution.
"The results raise the question: where on earth did the modern koala come from?" he said, adding that a lack of well-dated fossil records make it difficult to establish its true ancestor.
As regards the survival of one species and the extinction of the other, Dr Price said: "It's absolutely critical that we can find the answers to such questions, and that we find them soon, as it will go a long way in the planning of management strategies to conserve the modern koala well into the future." (ANI)