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The Associational Critique and the Late Pleistocene Extinction of North American Megafauna
Todd A. Surovell
Associate Professor
Dept. of Anthropology, University of Wyoming
Abrstract
Humans first arrived in North America approximately 14,000 years ago. Over the next two millennia, some 35 genera of Pleistocene megafauna suffered extinction. While it is tempting to see causality in this chronological correlation, after more than 80 years of fieldwork concerning the Pleistocene human occupation of the Americas, we can only demonstrate with confidence that humans hunted at most five species of extinct fauna. Fundamentally then, we must ask if it is possible that humans caused the extinction of some 35 genera of large mammals but left behind very little evidence of that act? This question is at the heart of what I call the "Associational Critique" of the overkill hypothesis. Critics of overkill argue that anthropogenic extinction will remain highly controversial until unambiguous material evidence of human hunting of a large number of taxa is discovered. In contrast, I will argue that a huge amount of circumstantial evidence points to humans as the primary causal agents of extinction, and that the associational critique puts forth unrealistic if not impossible requirements for the overkill hypothesis to fulfill.
Friday, September 24, 2010 – 4:00PM
Room AD 200 (Administration Bldg., 1201 5th St.)
Hosted by the
UC Denver Department of Anthropology
4 comments:
"I will argue that a huge amount of circumstantial evidence points to humans as the primary causal agents of extinction, and that the associational critique puts forth unrealistic if not impossible requirements for the overkill hypothesis to fulfill".
Whole-heartedly agree. Some people give the impression that they will refuse to accept the overkill hypothesis until someone produced CCTV footage of some human actually killing the last mammoth. And even then I'd expect them to claim it was an isolated act, and they wouldn't be convinced until they viewed more footage.
And any animal that humans killed and ate is unlikely to leave many remains for a start.
"In contrast, I will argue that a huge amount of circumstantial evidence points to humans as the primary causal agents of extinction"
And I thought of another example of 'circumstantial evidence'. The fact that megafauna extinction happen throughout much of the world, not just in North America, about the time humans arrive. Australia for example: extinctions at 46,000 years ago, some time after humans arrived. Central Eurasia: extinctions about 35,000 years ago. It's very difficult to find a single excuse for all the different dates. Of course it is possible there was no 'one' cause, but there does seem to be a common theme.
The more subtle issue is that overkill can be the cause of an extinction of many taxa without humans actually killing off every single one of them.
We have a very weak grasp of how robust complicated food webs are ecologically, and it probably wouldn't be ethical to use experiments other than "natural ones" or simulations to find out.
Predators can be surprisingly important to the lower tier chains of the food pyramid and the death of top tier prey can seriously disrupt predator numbers.
Good points Andrew, and I agree totally.
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