Chimpanzees at the Taronga Zoo in Sydney, Australia.
The human ego has never been quite the same since the day in 1960 that Jane Goodall observed a chimpanzee feasting on termites near Lake Tanganyika. After carefully trimming a blade of grass, the chimpanzee poked it into a passage in the termite mound to extract his meal. No longer could humans claim to be the only tool-making species. The deflating news was summarized by Ms. Goodall’s mentor, Louis Leakey: “Now we must redefine tool, redefine Man, or accept chimpanzees as human.”Read more at The New York Times
So what have we actually done now that we’ve had a half-century to pout? In a 50th anniversary essay in the journal Science, the primatologist William C. McGrew begins by hailing the progression of chimpanzee studies from field notes to “theory-driven, hypothesis-testing ethnology.”
He tactfully waits until the third paragraph ... to deliver the most devastating blow yet to human self-esteem. After noting that chimpanzees’ “tool kits” are now known to include 20 items, Dr. McGrew casually mentions that they’re used for “various functions in daily life, including subsistence, sociality, sex, and self-maintenance.”
... The tool for sex, he explained, is a leaf. Ideally a dead leaf, because that makes the most noise when the chimp clips it with his hand or his mouth. “Males basically have to attract and maintain the attention of females,” Dr. McGrew said. “One way to do this is leaf clipping. It makes a rasping sound. Imagine tearing a piece of paper that’s brittle or dry. The sound is nothing spectacular, but it’s distinctive.”
“The male will pluck a leaf, or a set of leaves, and sit so the female can see him. He spreads his legs so the female sees the erection, and he tears the leaf bit by bit down the midvein of the leaf, dropping the pieces as he detaches them. Sometimes he’ll do half a dozen leaves until she notices ... Presumably she sees the erection and puts two and two together, and if she’s interested, she’ll typically approach and present her back side, and then they’ll mate.”