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Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Who Killed the Elephants?
11 April 2005 (All day)
Hungry prehistoric hunters, not climate change, drove elephants and wooly mammoths to extinction during the Pleistocene era, new research suggests.
At least 12 kinds of elephants and mammoths used to roam the African, Eurasian, and American continents. Today, only two species of elephants are left in South Asia and sub-Saharan Africa. One theory for this dramatic demise holds that rapid climate shifts at the end of the most recent major ice age, some 10,000 years ago, altered vegetation and broke up habitats, causing the death of those unable to adapt to the new conditions. Another hypothesis blames prehistoric humans, whose improved weapons and hunting techniques allowed them to wipe out whole herds of elephants and mammoths (Science, 8 June 2001, p. 1888).
To help resolve the debate, archaeologist Todd Surovell of the University of Wyoming, Laramie, and colleagues tested two assumptions. If humans caused the elephant and mammoth extinctions, Surovell reasoned, the timing of the die-offs in specific regions should match human expansion into those regions. On the contrary, if the extinction of these mammals were due to climate change, elephants and mammoths should remain in regions already colonized by humans and would only begin to die off once climate change occurred.
The team tested both theories by analyzing where and when elephants and mammoths were killed. In all, the study included 41 archaeological sites on five continents. The researchers found that, as humans migrated out of Africa, they left a trail of dead elephants and mammoths in their wake. The creatures disappear from the fossil record of a region once it became colonized by humans. Modern elephants survived in refuges uninviting to humans, such as tropical forests, says Surovell, whose team reports its findings online this week in the Proceedings of the National Academy of Sciences.
Biologist R. Dale Guthrie of the University of Alaska in Fairbanks largely agrees with the findings, but he says more work is needed to explain why some mammoths seem to have survived in regions colonized by humans and why many modern elephants live in areas easily accessible to humans, such as the African savannah.
More on Guthrie's research