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What killed the mastodons, mammoths, and sloths of the Americas? Was it the weather (or, more accurately, the change in climate)? John Alroy thinks it was people. (John Alroy. A Multispecies Overkill Simulation of the End-Pleistocene Megafaunal Mass Extinction. Science 2001 292: 1893-1896.) Others aren't convinced, according to a short article by Leigh Dayton in the same issue. She writes, "At the American Museum of Natural History in New York City, biologists Ross MacPhee and Alex Greenwood blast Alroy's model, because they say overkill can't explain why the massive hunting stopped 10,000 years ago. Instead, he and Greenwood suspect that the huge animals succumbed to a highly contagious, lethal virus introduced by human newcomers." Apparently, the idea that these animals were overhunted by humans was proposed in 1967 by a University of Arizona geoscientist, Paul S Martin and reported by Martin and his colleague James Mosimann in a 1975 American Scientist article. (according to a University of Arizona Report on Research pamphlet, Spring/Summer 2001, p. 26) And what killed the large mammals, reptiles, and birds of Australia about 46,000 years ago? A team of researchers posit humans are responsible for this, too. (Richard G. Roberts, Timothy F. Flannery, Linda K. Ayliffe, Hiroyuki Yoshida, Jon M. Olley, Gavin J. Prideaux, Geoff M. Laslett, Alexander Baynes, M. A. Smith, Rhys Jones, and Barton L. Smith. New Ages for the Last Australian Megafauna: Continent-Wide Extinction About 46,000 Years Ago. Science 2001 292: 1888-1892) Leighton writes about their article, "Roberts and Miller think aborigines changed vegetation by burning the landscape, possibly to make hunting and traveling easier. The result: less food for big browsing animals, and hunting and climate fluctuations may then have tipped them to oblivion. 'The bulk of the evidence is now clearly aligned with a human explanation for the [Australian] event,' agrees Gifford Miller, a geochronologist at the University of Colorado, Boulder." |
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The University of Arizona Last update Sept 2, 2001 schmidtz@u.arizona.edu willott@u.arizona.edu "http://research.biology.arizona.edu/mosquito/willott/323/hotstuff.html" All contents copyright © 1998-2001. All rights reserved. |