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The media ruckus spurred by Pruetz's report of spear-wielding chimps made her absence as a speaker at last year's Mind of the Chimpanzee conference perplexing. She was in the audience but wasn't invited to present a paper. On top of that, Pruetz's post-doc adviser, Cambridge University primatologist William McGrew, made a passing reference to the Fongoli hunting behaviors but did not credit her with the work. He credited her co-author and former student Paco Bertolani, now a student of McGrew's. Bertolani witnessed the first—of now 40—observed instances of the behavior, but scientific etiquette would call for the principal investigator to be mentioned. McGrew apologized afterward. Some primatologists took Pruetz to task for overstating the bush-baby-spearing behavior. When your prey is smaller than your hand, are you really hunting? Male primatologists tend to make the distinction along gender lines: The traditional view has been that chimpanzee hunting—along with aggression and murder—is the domain of the male. "Small mammals that females and juveniles obtain are 'gathered,' " Pruetz says, "while males 'hunt.' " Females, the thinking goes, don't hunt because they don't need to; male chimps are thought by some to trade meat for sex, but Pruetz hasn't seen this at Fongoli.

I'm going to weigh in, for what it's worth. One day while accompanying Pruetz, I watched a young chimp named David at a bush baby tree hole. We heard him well before we saw him: a resounding THONK that caused Pruetz to stop in her tracks and go, "Hold on, hold the phone, that sounds like a spear!" We looked around, and there he was, standing on a branch in a kino tree, holding on with one hand and waving a thick, three-foot-long stick over his head. He slammed it down into the hole, then examined the tip. Concluding that no one was home, he took off, leaving the spear protruding from the hole. The violence and foresight with which he undertook his task did not suggest an animal quietly foraging. His aim was unmistakable: to kill, or at least incapacitate, whatever was in there.

Many of Pruetz's reviewers tripped over the word spear. For one thing, it suggests a projectile and a more Cro-Magnon-esque technique: something aimed and thrown. (Pruetz says she had spearfishing in mind when she chose the noun.) Stanford suggested bludgeon. But bludgeons are blunt, not sharpened. Another offered dagger. Someone else wanted bayonet. In the end, Pruetz took spear out of the title and worded her text more cautiously, making reference to a tool "used in the manner of a spear." (The press picked up on it anyway. "Spear-Wielding Chimps Snack on Skewered Bushbabies" ran the giddy headline.)

I asked Pruetz if perhaps she's been the victim of an alpha male primatologist conspiracy. She laughed it off. "Yeah, maybe I'm not pant-grunting enough." (The pant-grunt is an expression of submissiveness; a chimp that encounters a higher ranked peer and fails to pant-grunt is asking for trouble.) It's also possible that humans are simply resistant to the notion that anyone other than a human makes weapons for killing.

You would think that primatologists, more than other scientists, would be comfortable with the shifting boundaries between chimpanzee and human. Their gene sequences are around 95 to 98 percent the same. (This is less meaningful than it sounds. Humans share more than 80 percent of their gene sequence with mice, and maybe 40 percent with lettuce.) A recent exploration of the human and chimpanzee genomes, undertaken by David Reich and colleagues at the Broad Institute of MIT and Harvard in Cambridge, Massachusetts, suggests that chimpanzees and early hominins may have interbred after the two lines initially split. Yet there seems to be a lingering discomfort with findings that, as Pruetz puts it, "chip away at our superiority."

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