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(Headlines from the Seattle Times and the Dallas Morning News, section heads from the Arkansas Democrat-Gazette)
Chimpanzees, bonobos, and we
Are close twigs on the ape family tree.
If you study each cousin,
Then soon you'll be buzzin',
"Now I know why you're you and I'm me."
Even staunch supporters of Darwinian Evolution acknowledge the reason that many people find that theory hard to accept. We humans see ourselves as endowed with an intellect and culture (and, some would say, a soul) that set us apart from all other creatures.
We are rational beings with manners and ethics, while apes behave like -- well -- animals. And if scientific evidence persuades our logical minds that we are indeed evolved from apes, then surely we are more highly evolved than orangutans, gorillas, chimpanzees, and bonobos.
Emory University Primatologist Frans de Waal would not agree. Those species are as highly evolved as our own. Their evolution followed different tracks, and they have become as successful in their environments as we are in ours.
Hanging With the Apes
If we really want to understand what makes us human, de Waal argues in Our Inner Ape, we should not focus on our differences with apes, but rather examine the "fascinating and frightening parallels between primate behavior and our own, with equal regard for the good, the bad, and the ugly." That is precisely what he does in the book, with a wealth of stories and an entertaining style that does not sacrifice scientific depth or objectivity.
He focuses on chimpanzees and bonobos because they are closest to humans, sharing a common ancestor as recently as 5.5 million years ago. After humans branched off this lineage, ancestral chimps and bonobos remained a single species for 3 million more years. Genetic evidence indicates that humans are more closely related to bonobos than to chimps, but only slightly so.
The bonobo was discovered relatively recently, in 1929, in a Belgian museum by a scientist examining a skull that was similar in many ways to a chimp's but smaller. That explains the animal's original designation of pigmy chimpanzee, but de Waal notes the two species are as physically different "as a Concorde is from a Boeing 747."
"Even chimps would have to admit that the bonobo has more style," the author asserts as if channeling the mind of a chimpanzee. "A bonobo's body is graceful and elegant.... Females have breasts; they are not as prominent as in our species, but definitely A-cup compared to the flat-chested other apes."
"Chimps," he continues, "... look as if they work out every day. Bonobos have a more intellectual appearance ... [with] an eerily humanlike posture," comparable to "Lucy," modern humans' famous Australopithecus ancestor.
Lover or Fighter?
Appearance aside, the most remarkable differences between the two species are behavioral. Chimpanzees live in hierarchical male-centered groups where dominance and alliances depend on confrontation and physical prowess. Whether in the wild or in captivity, they live in Machiavellian social groupings, writes de Waal.
Bonobos, on the other hand, "make love, not war." They live in female-centered groups where erotic touching between individuals regardless of gender or age serves a social lubricant. Sex is remarkably casual, and "they know all the positions of the Kama Sutra, and even some positions that are beyond our imagination (such as both partners hanging upside down by their feet)."
Not that conflict among bonobos or cooperation among chimps is unknown, but the evolution of the two species, whether genetic or cultural, seems to have taken them down remarkably different paths.
Going to Extremes
Where do humans fit into this spectrum of behaviors? That question is always open for discussion as de Waal shares lively stories from his 30 years of primatology research.
The book's organization guides readers toward an interesting set of conclusions. Having introduced family ties among the species, Machiavellian power, and sexual politics in the first three chapters, de Waals moves onward to violence and reconciliation ("From War to Peace"), then to kindness and altruism ("Bodies with Moral Sentiments").
The concluding chapter describes our species as "The Bipolar Ape," a creature whose challenge is to strike a balance between love and war, between competition and cooperation, between the needs of self and the needs of the group.
Here, de Waal examines the range of possibilities that evolution, both genetic and cultural, has made possible for our distinct species of ape. At this point, the book leaves the realm of concrete science for a more speculative path. It leaves the Darwinian view of natural selection for an almost Marxist concept of forces in dialectic opposition.
According to De Waal, human nature is the result of "tamed contradictions," just as the violent nature of chimpanzees makes their ability to achieve peace all the more remarkable. Our species is endowed with the full range of possibilities of both our cousins.
"Being both more systematically brutal than chimps and more empathic than bonobos, we are by far the most bipolar ape. Our societies are never completely peaceful, never completely competitive, never ruled by sheer selfishness, and never perfectly moral."
Where are We Headed?
Overlying these dualities is human intelligence, which has changed the very nature of evolution itself. While other species evolve in response to changes in the external environment, our species transforms the environment to suit its needs.
In that sense, we no longer need to evolve, but in another sense we are influencing our evolution, possibly in a negative direction. We have changed the rules of survival by pharmacology, technology, or surgical intervention. Are we permitting the procreation of characteristics that would normally lead to an individual's failure to thrive or reproduce, such as women with narrow vaginal canals who give birth through caesarean sections to babies with large heads?
Questions like those may strike de Waal's readers as surprising. For most of its pages, this is a book intended to produce an understanding of the evolutionary heritage of human nature -- as the subtitle states, "Why we are who we are."
But then it turns to the open question of who -- or what -- our species may become. Perhaps that is the point at which even the most committed Darwinist needs a new theoretical or philosophical foundation.