Richard Wrangham doesn’t immediately strike you as the troglodytic type. Originally from Hertfordshire, England, Wrangham speaks in the clipped, confident tones of an Oxbridge don (he attended both Oxford and Cambridge). Balding and slightly rumpled, he is the picture of tweedy intellectualism. His tales of Africa, though, point to the ease with which men can slip back into their ape-like ways. "When you see these [chimpanzee] battles, you feel incredibly pumped," he says. "It goes right through your gut: these great balls of black fur racing through the bush. It’s scary, but there’s also the thrill of us-against-them, because, obviously, you want your side to win. It’s amazing how easily our Western-derived tendencies for sympathy get eroded in the face of these sorts of excitements."

His enthusiasm for this violence, though, may be less ape-like than it is guy-like.

According to Wrangham, blame for the high levels of violence in chimpanzee and human societies can be placed squarely at the feet of males (hence Demonic Males). In the course of our evolution, he says, aggressive males have enjoyed greater reproductive success; therefore, the process of natural selection has favored violent behavior. By extension, patriarchal societies exhibit similar tendencies. "America, as the dominant power in the world, is involved in more aggressive interactions than any other country," he says. "It’s the same with chimpanzees: the alpha male is always involved in putting down threats they see about them; they’re always breaking up alliances, challenging rivals."

Furthermore, Wrangham says, the kind of low-risk warfare characterized by a group of chimps launching a surprise attack on an individual — a common tactic among the animals — is analogous to the low-risk warfare favored by America’s modern military culture. A stick and a Stealth bomber may be light-years apart in terms of technology, but both shift the balance of power in favor of the individual — or nation — who wields them.

In chimpanzee societies, Wrangham continues, conflict usually breaks out as a result of power imbalances. Chimps, like the ones who ripped the testicles from the unfortunate ape in Wrangham’s photographs, generally will not attack in the absence of overwhelming force. The same principle applies to men. When the US and the USSR faced off during the Cold War, for instance, the balance of power between the two nations prevented armed conflict. Today, the only thing preventing all-out war against Iraq may be the fact that the US has so far failed to muster adequate coalition support.

The fact that America is amassing forces in the Gulf region, then, may be little more than an elaborate display — the equivalent of a chimp’s chest-thumping and dirt-flinging. Or it may signal something more dire. "The fascinating thing about the first Gulf War is this unresolved status challenge," Wrangham says. "With chimps and humans, conflict seems to be driven by more than simple strategic considerations. There is this added level of concern over status. The people who are making the decisions — Rumsfeld, Cheney — they are all part of this previous victory that nonetheless did not lead to a resolve in status between the leaders of the two countries. In chimpanzees, there is nothing that predicts aggression so well as when there are unresolved status challenges. It’s hard for me to say this is going to be peacefully resolved unless Saddam Hussein makes some major concessions."

Even more ape-like, Wrangham says, is our ongoing conflict with Al Qaeda. When the hijackers turned jets into missiles on September 11, they may have been initiating a terrible new form of warfare, but they were also reverting back to the kinds of lethal raids practiced by chimps and, subsequently, pre-industrial man. "In primitive society, this is what war consisted of," Wrangham says. "Setting fire to a hut with 50 people in it, or attacking the World Trade Center." In an ironic twist, the mighty American military machine — with all its sophistication and firepower — has also reverted back to this primitive form of warfare. The current emphasis on Special Operations missions — with their covert actions and quick-hit raids — is a weirdly atavistic military strategy, not so far removed from the stealthy chimp patrols in Uganda.

"This is very alarming," Wrangham says. "Traditional warfare — mutual raiding — is very difficult to stop. It is much more punishing on everybody. There is just much more suffering. The ability to protect against raids is something that predicts relative peacefulness. People have to recognize that the old systems of protection are not going to be adequate. This is the message from Al Qaeda. The message is that now more than ever, we need a moral agreement in the world, because military agreements and military tactics are going to be very ineffective against mutual raiding."

He adds: "I accept the overall message that reality is tough."

Then, perhaps aware that his visitor is about to leap from the nearest window, Wrangham provides a little glimmer of hope: "Overall, the pattern of statehood and nation growth has led to reduced levels of conflict," he says, though without much conviction. Wrangham also points out that his Demonic Males presents "a nice balance: here’s the bad news, here’s the good news." In fairness, after 250 pages of testosterone-drenched strife, the book does end by reminding us that human beings are also closely related to bonobos — petite, chimp-like creatures who live in peaceful, matriarchal societies, and who would much rather engage in lengthy and elaborate sexual encounters with each other than fight. Even the book’s villains, male chimps, are partly redeemed in the closing pages.

In May 1993, Wrangham reveals in his book’s final chapter, he looked on with fascination and delight as Kakama, a two-year-old chimp, dragged a little lump of wood behind him — "like Christopher Robin with Winnie-the-Pooh. Bump bump bump." For the entire day, Kakama went to great pains to hang on to his piece of wood, and at one point tenderly placed it in a little nest he had built. "I had just watched a young male chimpanzee invent and then play with a doll," Wrangham writes. "A doll!" Today, Kakama’s little log-doll resides in a glass case at the Peabody Museum, just downstairs from Wrangham’s office. Recently, the artifact was joined by a few others: a collection of ordinary, harmless-looking sticks.

Chris Wright can be reached at cwright[a]phx.com