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May 30, 2005

Man didn't kill off mega-marsupials (perhaps)

New research suggests that Australian mega-fauna were not killed off by the arrival of human beings ~50 K B.P., rather, climate change was the culprit. I think the problem with the way these sort of studies are presented is that there is the assumption that there needs to be a silver bullet which "explains" a given phenomenon. Clearly, after tens of thousands of years of "coexistence" humans were to some extent part of the environment of these marsupials, so their extinction might simply have been the outcome of the intersection of climate and H. sapiens facility at expanding into new niches and blocking the "bounce back" of mega-fauna. Evolution is as much (if not more), as highlighted by the "Red Queen Hypothesis," a matter of coevolution between life forms as response to environmental stimuli. Additionally, man can reshape the environment, adding another confounding variable into the model. In other words, climate change might have been a necessary condition for mega-faunal extinction, but it was not sufficient.

Posted by razib at 08:21 PM