Time magazine did one of those Evolution updates last week, "How We Became Human," on its cover. There wasn't too much new -- just how little we differ genetically from chimpanzees.
Yet there was one sentence that stood out like a lightning bolt. It has enormous implications for understanding how human societies evolved and why they sometimes find it difficult to get along with each other. Here it is:
[T]he principle of gene-by-gene comparison [between species] remains a powerful one, and just a year ago geneticists got hold of a long-awaited tool for making those comparisons in bulk. Although the news was largely overshadowed by the impact of Hurricane Katrina... the publication of a rough draft of the chimp genome in the journal Nature immediately told scientists several important things. First they learned that overall, the sequences of base pairs that make up both species' [i.e., humans and chimps] genomes differ by 1.23% -- a ringing confirmation of the 1970 estimates -- and that the most striking divergence between them occurs, intriguingly, in the Y chromosome, present only in males.
Did you see that? It deserves much more attention than Time was willing to give it. Basically, the point is that, in crossing the little evolutionary distance that exists between chimps and humans, most of the changes occurred in males. In other words, what differentiates us from our mammalian relatives is changes that have occurred in the male of the species.
Actually, this is not news. Evolutionary anthropologists have long been aware of it. As far back as 1972, Elaine Morgan, a feminist, writing in The Descent of Woman, noted that in fact the role of females hadn't changed much from chimp to human. Mothers nurse and care for their offspring in basically the same way chimps do. In terms of social role, there really isn't much difference between human females and other animals.
What has changed is the role of males. Among chimps, males hang out in groups, form alliances, forage together, and do a lot of bickering over status. They do not participate at all in child rearing. By the time hunting-and-gathering tribes arrive, however, men have been folded into the family. Monogamy predominates and both parents participate in child rearing. The extraordinary innovation is "fatherhood," a role that doesn't really exist elsewhere in nature.
Last March in The American Spectator I wrote an article entitled "The Alpha Couple and the Primal Horde," speculating how this transformation might have taken place. Without recounting the whole argument, let's review some of key ways in which chimp society is unique among other mammals and how it might have evolved into human society.
One very unusual quality about East African chimps -- our closest relatives -- is that they are patrilocal. While females usually form the backbone of most mammalian societies, chimp troops are built around closely related males. They form a "brotherhood" that defends territory and keeps a population of females within its borders. (Interestingly, dolphins, the other species that most closely matches human intelligence, do the same thing.) Females usually stay within their native group but sometimes migrate to other troops -- something that males never do. In addition, these male bands occasionally go to war with neighboring troops, expanding their territory and capturing other females.
This social pattern does not even predominate among other chimp species. The notable example is the bonobo or "pygmy" chimps, a slightly more distant cousin of ours that lives in the deepest jungles of Central African. Among bonobos, females predominate and males out-migrate. The "sisterhood" of females is the core structure -- just as in most mammalian societies. Males even draw their rank from their mothers and are often physically defended by them, even after reaching maturity.
Bonobos are an easy-going species that indulge constantly in sex, both heterosexual and homosexual. In fact, ethnologists describe bonobo sex as a form of social conviviality that keeps tensions at a minimum. Frans de Waal, a Dutch scientist who has written extensively about bonobos, continually holds up this female dominance and the relative placidity among bonobos as a negative contrast to human society. Writing in Scientific American, he says:
At a juncture in history during which women are seeking equality with men, science arrives with a belated gift to the feminist movement. Male-biased evolutionary scenarios -- Man the Hunter, Man the Toolmaker and so on -- are being challenged by the discovery that females play a central, perhaps even dominant, role in the social life of one of our nearest relatives. In the past few years many strands of knowledge have come together concerning a relatively unknown ape with an unorthodox repertoire of behavior: the bonobo.
In fact, the discovery of bonobo society proves just the opposite. It is precisely because females play a dominant role and males are so passive and unambitious that bonobos did not produce an evolutionary line that led to human beings. Instead, they remain a relatively minor, underpopulated species holding their orgies deep in the jungle. The larger East African chimp, where males predominate, produced the line that led to humanity.
What is it about this "male brotherhood" that points the way to human evolution? First of all, male chimps have learned to work with each other in co-operative effort -- something nearly all other species don't do. Chimps have very rigorous rules about sharing females. Each male is allowed to mate with each female. As Sarah Blaffer Hrdy, author of The Woman Who Never Evolved, has pointed out, this "confuses paternity," allowing each male to think that a female's offspring might be his own. This dampens sexual jealousy and eliminates the very cruel practice in other species where an alpha male will kill off any rival male's offspring in order to put females to work in producing his own.
Most important, male bonding enables chimps to practice cooperative hunting. Meat constitutes about 10 percent of their diet -- a figure that would rise steadily as humans evolved. Jane Goodall describes a scene where a troop of male chimps was foraging in the trees among a group of monkeys. Almost imperceptibly, without any overt signals, the chimps moved into positions where they had one young monkey isolated on a tree branch. Suddenly they pounced and killed him, sharing the meat. It is easy to see how chimp troops could have taken such skills onto the East African savannah, where the earliest human evolution occurred. Human tribes did not become big-game hunters for millions of years but they probably survived as scavengers and hunters of small game in the earliest stages. In an environment where rivals and predators were swift and common, this male cooperation was the only hope of survival.
As I outlined in "The Alpha Couple and the Primal Horde," in the new savannah environment, the crucial key to keeping a group of males together while avoiding sexual jealousy would have be monogamy. The chimp ritual of having every ovulating female mate with every male -- which often takes more than a week -- would be too distracting and time-consuming in the much more dangerous savannah environment. Nor would reverting to polygamy solve the problem. Polygamous species such as the gorilla form "harems," where a dominant male collects a large number of females while subdominant males are pushed into an isolated "bachelor herd." This works for the powerful gorilla, which has no natural predators. But it would have been impossible for a diminutive species of three-foot-tall chimpanzees trying to survive on the savannah. The advantage of monogamy is that it keeps the group together, since each member is guaranteed a mate.
Coincidentally (or was it perhaps Intelligent Design?), this conversion to monogamy also offered irreplaceable advantages in child rearing. The enlistment of males to child rearing made possible the development of human intelligence. The combination of enlarging brains and the new upright stature made birth more difficult for protohuman females. As a result, all humans are born premature -- earlier than body size would dictate and in a much greater state of helplessness than other creatures in nature. The evolution of human intelligence would have been impossible without the change in male role and the adoption of monogamy. For that reason, it is not at all surprising to find that the key genetic changes have occurred on the male chromosome.
So what does all this suggest for the present? First, it says that feminism, in its most obviously primitive forms, is undermining human evolution. Everywhere in the Western world, the emancipation of women has initially led to rising divorce rates and plummeting births. After intelligent consideration, however, many "second-generation" feminists have been able to handle both careers and families, which means the human family may be able to reconstitute itself on a more equitable basis.
The real changes are on the other side of the world, however, where Muslim societies have regressed to polygamy, a form of marriages that was not present in the earliest stages of human evolutionary history. This has led to a re-creation of the "bachelor herd" -- a disgruntled population of excess males, which Islam has always handled very skillfully by turning it into an army of jihad warriors.
The brotherhood of males, the invention of "fatherhood," the creation of monogamous marriage within a larger social unit -- these have been the pathways to human evolution. Sustaining the family while keeping rival brotherhoods from becoming too murderous in their competition will be the key to keeping the experiment going.
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