The Japan Times, July 22, 1997
By ROBIN McKIE
Egalitarian chimps offer a glimpse of our erotic past
LONDON—Peering into the eyes of a pygmy chimpanzee may reveal a strange secret: a glimpse of our ape-man ancestors.
Scientists now believe these graceful cousins of the common chimpanzee share many features with australopithecines, the 4-million-year-old forebears of Homo sapiens.
According to Professor Frans de Waal of the Yerkes Regional Primate Center in Atlanta, the pygmy chimpanzee, or bonobo, is probably the best model we have of the so-called missing link.
But as de Waal stresses in "Bonobo: The Forgotten Ape," published this month, this does not mean bonobos are the missing link. He and fellow researchers merely argue that bonobos resemble more closely the type of creature from which we evolved than any other living animal.
"The bonobo may have undergone less transformation than either humans or chimpanzees, and could most closely resemble our common ancestor," states de Waal.
As a result, when we look at these creatures, we see features that have changed only slightly over the past 6 million years: diminutive stature, long arms and small brains.
This similarity has profound implications for understanding our nature and evolution. It is believed that humans and apes shared a common ancestor about 6 million years ago. Then the two lines began evolving in different directions until, 3 million years ago, the ape line split in two. One led to the chimpanzee, the other to a slightly smaller, more graceful type of ape: the bonobo.
But until recently, little was known about the bonobo, and most comparisons between our behavior and that of the apes concentrated on similarities between chimps and humans.
As a result, it was assumed that male-dominated, fairly violent societies are the norm. Recent work on the bonobo challenges this assumption, however.
"Had bonobos been known earlier, reconstruction of human evolution might have emphasized sexual relations, equality between males and females and the origin of the family, instead of war, hunting, tool technology and other masculine fortes," says de Waal.
Ignorance about bonobos stems from the fact that they were only discovered in 1929, and that there are only about 10,000 members of the species, all living in a fragment of forest in central Zaire.
However, when bonobos were studied by scientists, they produced a distinct shock, for the creatures were found to have staggering sexual appetites. As a consequence, they have been depicted as satyrs who will have sex at the drop of a hat—or a banana, an apple, or anything else that succumbs to the effects of gravity.
And it is true they have a healthy urge to have sex. As de Waal puts it, "Bonobos engage in sex in virtually every partner combination."
These combinations include penis-fencing—in which two males hang face to face from a branch while rubbing their erect penises together—as well as sporadic oral sex, massage of another's genitals and intense tongue-kissing. On the other hand, it should be added that the average copulation lasts only 13 seconds.
This behavior has a basic ulterior— but unconscious—motive. Sex is used as a substitute for aggression, as a means of defusing tension. For example, after a female hits a juvenile, the latter's mother may lunge at the aggressor, an action that is immediately followed by genital rubbing between the two adults.
And in this nonviolent society, freed from the fear of male aggression, females control food resources and dominate the males. "Bonobos provide a concrete alternative to macho evolutionary models derived from the behavior of baboons and chimpanzees," adds de Waal. "They also thoroughly upset the idea that sex is solely intended for procreation. From now on, any reference to biology in support of this claim will backfire."
However, similarities that we have with bonobos, or for that matter chimps, are not sufficient on their own to explain every aspect of human evolution, de Waal acknowledges. Special factors have produced unique human characteristics, particularly the nuclear and extended families, in which males and females share the raising of offspring—a phenomenon unique in the ape world and whose origin is not yet understood.
Nevertheless, nonaggressive bonobos, with their powerful female lobby and egalitarian social structure, provide as useful a model for understanding human evolution as any other species, particularly as it is based on an animal with which we share 98 percent of our genetic makeup. As de Waal says, "If we look after the bonobo, we may for a long time share this planet with a family member that affords us an entirely new look at ourselves."