A science journalist examines the links that separate humans, chimps.
BY DEBORAH BLUM
ALMOST CHIMPANZEE: Searching for What Makes Us Human, in Rainforests, Labs, Sanctuaries, and Zoos. Jon Cohen. Times. 369 pages. $27.50.
During the early 1920s, the pioneering primatologist Robert Yerkes kept two young chimpanzees -- named
Chim and Panzee -- at his home to observe them in a human environment. He became particularly attached to
Chim (later identified as a bonobo), admiring the animal's obvious intelligence and generous nature. When
Panzee became ill, Chim actively tried to comfort and care for her. Yerkes described this behavior in a
1925 book he titled Almost Human, although he worried about ``idealizing an ape.''
Researchers don't worry about about idealizing chimpanzees or emphasizing their similarities to humans
anymore. The shift is largely credited to the fieldwork and educational activism of Jane Goodall. Indeed,
as Jon Cohen points out in his gently provocative new book, the conservation-minded Goodall deliberately
dwelled on people-parallels. ``She believed that a critical mass of humans would most likely come to her
cause if they imagined their own hands reaching for the curl of a chimpanzee's finger.''
But today, Cohen suggests, may be time to dwell again on our differences. Chimpanzees are well
established as our closest cousins on Earth; some research sets the genetic difference at a mere one
percent. But even that slight deviation set us on widely divergent evolutionary paths and provided only
one species with real power over life on Earth. ``Humans will determine the fate of chimpanzees,'' Cohen
notes. ``Chimpanzees of course will have no say in the fate of humans.''
Cohen's book, then, is a meticulous exploration of how small quirks and large kinks in biology and
culture led to such different destinations. He searches for the best evidence of when human and
chimpanzee ancestors first separated -- usually fixed at about five million years ago -- and whether the
break was genuinely dramatic. He mulls over why small genetic variances have such enormous impact,
leading him into a wonderfully weird discussion of whether human-chimp hybrids are possible.
Cohen compares everything from essential body parts to fertility issues. For instance, while healthy
human males produce an average of 66 million sperm per milliliter, chimpanzees apparently clock in closer
to an average of 2.5 billion. ``Logically enough, higher sperm counts require larger testicles,'' he
writes, citing evidence that the ratio is 3:1 in favor of chimps.
A longtime correspondent for the journal Science, Cohen has a gift for unearthing small and telling
details. He occasionally falls into a research-publication style of storytelling which undermines his
effectiveness. But Almost Chimpanzee is not intended as a literary meditation on our place in the natural
world. It is a briskly told, clearheaded survey of research that looks at the innate differences between
two closely linked species, never forgetting that one of those species -- at least for now -- stands as
the most successful.
http://www.miamiherald.com/2010/09/19/1829583/understanding-our-closest-furry.html
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