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Arms and The (Female) Chimp I Sing

Posted by Richard Conniff on February 22, 2007

chimp-that-hunts-with-spear.jpg

It’s not just that chimpanzees use tools. Now it seems that they also manufacture a weapon for hunting. It’s a stick gnawed to a spear point, and the maker jabs it into tree hollows in an attempt to extract luscious, but highly mobile, bushbabies. Current Biology reports that biologists witnessed 22 instances of the behavior in the savanna habitat of southeastern Senegal. It’s the not first time biologists have reported chimpanzees hunting with tools. But the only other instance was one female chimp in Tanzania using a branch to roust a squirrel from a hollow.

Here’s the most interesting thing about the Current Biology report: The tool-using hunters were once again mostly females or juveniles. Hunting among chimpanzees is mainly an adult male activity. So the researchers suggest that individuals whose social or physical status doesn’t give them ready access to meat are forced to exploit niches the big boys ignore–like bushbabies holed up in trees–and use tools where males rely more on brute force and cooperative hunting. Subordinate social status may also be why female, but not male, bottlenose dolphins use tools.

The savanna chimps live in the same sort of grassland and woodland habitat where our own ancestors evolved. Early hominids may have been using jabbing sticks and throwing rocks in such a habitat up to six million years ago. The authors of the Current Biology article don’t quite come out and say it in so many words. But they’re clearly thinking that females may have been more important than males in developing our own primal hunting technologies. (Hmm. And what might that suggest about the origins of mechanized warfare?)

The bad news is that only one of the 22 reported attempts actually yielded a bushbaby. And the good news? The hunter, an adolescent female, got to eat her prey without sharing, even though a bunch of big lunky adult males were standing around watching.

For more information: Pruetz et al.: “Savanna Chimpanzees, Pan troglodytes verus, Hunt with Tools.” Publishing in Current Biology 17, March 6, 2007. www.current-biology.com

Photo: Tia is an adolescent female chimp who displayed the tool-use hunting behavior frequently. Photo credit: Maja Gaspersic / Courtesy of Iowa State University)

Check out NPR’s amusing Wagnerian/Hitchcockian take on this story at http://www.npr.org/templates/story/story.php?storyId=7584967

And while you’re visiting NPR, also have a listen to my commentary from Friday night on global warming offset scams http://marketplace.publicradio.org/shows/2007/02/23/PM200702237.html

Text copyright © 2007 by Richard Conniff

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