Tuesday, August 23, 2005

Study shows big game hunters, not climate change, killed off sloths


GAINESVILLE, Fla. --- Prehistoric big game hunters and not the last ice age are the likely culprits in the extinction of giant ground sloths and other North American great mammals such as mammoths, mastodons and saber-toothed tigers, says a University of Florida researcher.

Determining whether the first arrival of humans or the warm-up of the American continent at the end of the last Ice Age was responsible for the demise of prehistoric sloths has puzzled scientists because both events occurred at the same time, about 11,000 years ago. But by using radiocarbon to date fossils from Cuba and Hispaniola, where humans appeared later than on the North American continent, long after the last Ice Age occurred, UF ornithologist David Steadman was able to separate the two events.

He and his colleagues found the last record of West Indian ground sloths coincided with the arrival of humans 4,400 years ago. The results are published in a Proceedings of the National Academy of Sciences paper this week.

[...]

Steadman said he was not surprised to find that humans were more significant than changes in climate because most species of plants and animals can adjust to changes in temperature. However, the transition between the glacial and inter-glacial period, which resulted in shifts in habitat and the ranges of plants, may have made animal species more vulnerable than they otherwise would have been, he said.

"This is the first time it's been demonstrated for West Indian ground sloths, and West Indian ground sloths are sort of the poster child of big extinct West Indian mammals," he said. "I think this will go a long way to finally put to rest this whole idea that large extinct animals from the West Indies died out in the Ice Age during the Pleistocene Epoch."

Read more here.

Makes for a interesting commentary about the so-called 'living in haromony with nature' myth that gets tossed around wrt the Native Americans/First Nations. Anyone who looks closely can see that's not really the case. Myths, no matter which culture they're from, do more disservice than help.

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