New Reseach Supports UA Geoscientist's Theory That Humans, Not Climate, Killed Off Megafauna

Lori Stiles
June 7, 2001

Tomorrow's issue of Science publishes an article that presents new evidence that human "overkill" rather than climate change is why giant animals went extinct at the end of the Pleistocene. John Alroy of the National Center for Ecological Analysis, University of California - Santa Barbara, who did post-doctoral research at the University of Arizona, is lead author of the report.

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The controversial idea that large animals that once roamed North America and other continents disappeared from the face of the Earth because they were overhunted by early man was first proposed in 1967 by UA geoscientist Paul S. Martin, and published by Martin and James Mosimann in a 1975 article in American Scientist.

Alroy, who takes a quantitative approach to extinctions, "has published a much more sophisticated study than our original one. He presents powerful new evidence for overkill. It's nice to have someone fresh on deck (in this debate), " Martin said this morning. According to Alroy's analysis, Martin added, 300,000 people could have taken care of the North American mammoths, mastadons, sloths, etc. around 13,000 years ago.

A second new study, by Australian scientists Richard Roberts and Timothy Flannery, using new dating techniques, says that large-size mammals, reptiles and birds became extinct in Australia 46,000 years ago - a time that also coincides with the arrival of early man on that continent, Martin noted. In the New World, and in the Old, the chronology of megafaunal extinctions is in step with the spread of prehistoric humans.

Martin, UA professor emeritus of geosciences, is at a field site near Naco, Ariz., today, but can be reached tonight at his home, 520-792-3406, or tomorrow at his cellular phone number 520-471-6757, or at the UA Desert Laboratory, 520-629-9459.


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