Though de Waal stopped short of placing bonobos in a state of blissful serenity (he acknowledged a degree of bonobo aggression), he certainly left a reader thinking that these animals knew how to live. He wrote, “Who could have imagined a close relative of ours in which female alliances intimidate males, sexual behavior is as rich as ours, different groups do not fight but mingle, mothers take on a central role, and the greatest intellectual achievement is not tool use but sensitivity to others?”
The appeal of de Waal’s vision is obvious. Where, at the end of the twentieth century, could an optimist turn for reassurance about the foundations of human nature? The sixties were over. Goodall’s chimpanzees had gone to war. Scholars such as Lawrence Keeley, the author of “War Before Civilization” (1996), were excavating the role of warfare in our prehistoric past. And, as Wrangham and Peterson noted in “Demonic Males,” various nonindustrialized societies that were once seen as intrinsically peaceful had come to disappoint. Margaret Mead’s 1928 account of a South Pacific idyll, “Coming of Age in Samoa,” had been largely debunked by Derek Freeman, in 1983. The people identified as “the Gentle Tasaday”—the Philippine forest-dwellers made famous, in part, by Charles Lindbergh—had been redrawn as a small, odd community rather than as an isolated ancient tribe whose mores were illustrative. “The Harmless People,” as Elizabeth Marshall Thomas referred to the hunter-gatherers she studied in southern Africa, had turned out to have a murder rate higher than any American city. Although the picture was by no means accepted universally, it had become possible to see a clear line of thuggery from ape ancestry to human prehistory and on to Srebrenica. But, if de Waal’s findings were true, there was at least a hint of respite from the idea of ineluctable human aggression. If chimpanzees are from Hobbes, bonobos must be from Rousseau.
De Waal, who was described by Time earlier this year as one of the hundred influential people who “shape our world,” effectively became the champion—soft-spoken, baggy-eyed, and mustachioed—of what he called the “hippies of the primate world,” in lectures and interviews, and in subsequent books. In “Our Inner Ape: A Leading Primatologist Explains Why We Are Who We Are” (2005), he wrote that bonobos and chimpanzees were “as different as night and day.” There had been, perhaps, a vacancy for a Jane Goodall figure to represent the bonobo in the broader culture, but neither Hohmann nor Kano had occupied it; Hohmann was too dour, and Kano was not fluent in English. Besides, the bonobo was beyond the reach of all but the most determined and best-financed television crew. After 1997, that Goodall role—at least, in a reduced form—fell to de Waal, though his research was limited to bonobos in captivity. At the time of the book’s publication, de Waal told me, he could sense that not everyone in the world of bonobo research was thrilled for him, “even though I think I did a lot of good for their work. I respect the field workers for what they do, but they’re not the best communicators.” He laughed. “Someone had to do it. I have cordial relationships with almost all of them, but there were some hard feelings. It was ‘Why is he doing this and why am I not doing this?’ ”
De Waal went on, “People have taken off with the word ‘bonobo,’ and that’s fine with me”—although he acknowledged that the identification has sometimes been excessive. “Those who learn about bonobos fall too much in love, like in the gay or feminist community. All of a sudden, here we have a politically correct primate, at which point I have to get into the opposite role, and calm them down: bonobos are not always nice to each other.”
At the Lui Kotal camp, which Hohmann started five years after being expelled from Lomako, the people who were not tracking apes spent the morning under the Audubon calendar, as the temperature and the humidity rose. Ryan Matthews put out solar panels, to charge a car battery powering a laptop that dispatched e-mail through an uncertain satellite connection. Or, in a storage hut, he arranged precious cans of sardines into a supermarket pyramid. We sometimes heard the sneezelike call of a black mangabey monkey. For lunch, we ate cassava in its local form, a long, cold, gray tube of boiled dough—a single gnocco grown to the size of a dachshund. A radio brought news of gunfire and rocket attacks in Kinshasa: Jean-Pierre Bemba, the defeated opposition candidate in last year’s Presidential elections, had ignored a deadline to disarm his militia, and hundreds had been killed in street fighting. The airport that we had used had been attacked. The Congolese camp members—including, at any time, two bonobo field workers, a cook, an assistant cook, and a fisherman, working on commission—were largely pro-Bemba, or, at least, anti-government, a view expressed at times as nostalgia for the rule of Mobutu Sese Seko. Once, they sang a celebratory Mobutu song that they had learned as schoolchildren.
“It was so easy for Frans to charm everyone,” Hohmann said of de Waal one afternoon. “He had the big stories. We don’t have the big stories. Often, we have to say, ‘No, bonobos can be terribly boring. Watch a bonobo and there are days when you don’t see anything—just sleeping and eating and defecating. There’s no sex, there’s no food-sharing.’ ” During our first days in camp, the bonobos had been elusive. “Right now, bonobos are not vocalizing,” Hohmann said. “They’re just there. And if you go to a zoo, if you give them some food, there’s a frenzy. It’s so different.”
Captivity can have a striking impact on animal behavior. As Craig Stanford, a primatologist at the University of Southern California, recently put it, “Stuck together, bored out of their minds—what is there to do except eat and have sex?” De Waal has argued that, even if captive bonobo behavior is somewhat skewed, it can still be usefully contrasted with the behavior of captive chimpanzees; he has even written that “only captive studies control for environmental conditions and thereby provide conclusive data on interspecific differences.” Stanford’s reply is that “different animals respond very differently to captivity.”
In the wild, bonobos live in communities of a few dozen. They move around in smaller groups during the day, in the pattern of a bus-tour group let loose at a tourist attraction, then gather together each night, to build new treetop nests of bent and half-broken branches. But they stay in the same neighborhood for a lifetime. When Hohmann found bonobos on his first visit to Lui Kotal, he could be confident that he would find the same animals in subsequent years. On this trip, the bonobos had been seen, but they were keeping to the very farthest end of Hohmann’s twenty-thousand-acre slice of forest: a two-hour walk away. (“They are just so beautiful,” Andrew Fowler, the British habituator, said, after seeing them for the first time. “I can’t put it any other way.”) There was talk of setting up a satellite camp at that end—a couple of tents in a small clearing—but weighing against the plan was the apparently serious risk of attack by elephants. (Forest elephants headed an impressive lineup of local terrors, above leopards, falling trees, driver ants, and the green mambas that were sometimes seen on forest paths.) So the existing arrangement continued: two or three people would go into the forest and hope to follow bonobos to their nest site at night; the following day, two or three others would reach that same point before dawn.
When I went out one morning with Hohmann and Martin Surbeck, the Swiss Ph.D. student, the hike began at a quarter to four, and there were stars in the sky. We walked on a springy path—layers of decaying leaves on sand. I wore a head torch that lit up thick, attic-like dust and, at one moment, a bat that flew into my face. We stepped over fallen tree trunks in various states of decay, which sprouted different kinds of fungus; after an hour or so, we reached one on which local poachers had carved a graffiti message. Poachers, whose smoked-bonobo carcasses can fetch five dollars each in Kinshasa’s markets, have often been seen in the forest, and their gunfire often heard. Their livelihood was disrupted last year when Jonas Eriksson, a Swedish researcher on a visit to Lui Kotal, burned down their forest encampment. I was later given a translation of the graffiti: “JONAS: VAGINA OF YOUR MOTHER.”
Hohmann stopped walking at half past five, at a point he knew to be within a few hundred feet of where the bonobos had nested. Bonobos sleep on their backs—“maybe holding to a branch with just one foot, and the rest of the body looking very relaxed,” Hohmann had said, adding that “nest-building is the only thing that sets great apes aside from all other primates.” (He speculates that the REM-rich sleep that nests allow may have contributed to the evolution of big brains.) We would hear the bonobos when they woke. When we turned off our flashlights, there was a hint of light in the sky, enough to illuminate Surbeck using garden clippers to cut a branch from a tree and snip it into a Y shape about four feet long; he tied a black plastic bag across the forked end, to create a tool that hinted at a lacrosse stick but was designed to catch bonobo urine as it dripped from treetops. Surbeck’s dissertation was on male behavior: he would measure testosterone levels in the urine of various bonobos, in the hope that power structures not easily detected by observation would reveal themselves. (If an evidently high-ranking male had relatively low testosterone, for example, that might say something about the power he was drawing from his mother. A male bonobo typically has a lifelong alliance with its mother.)
There was a rustle of leaves in the high branches, like a downdraft of wind. To walk toward the sound, we had to leave the trail, and Surbeck cut a path though the undergrowth, again using clippers, which allowed for progress that was quieter, if less cinematic, than a swinging machete. We stopped after a few minutes. I looked upward through binoculars and, not long afterward, removed the lens caps. The half-light reduced the forest to blacks and dark greens, but a hundred feet up I could see a bonobo sitting silently in the fork of a branch. Its black fur had an acrylic sheen. It was eating the tree’s small, hard fruit; as it chewed, it let the casing of each fruit fall from the corner of its mouth. The debris from this and other bonobos dropped onto dead leaves on the forest floor, making the sound of a rain shower just getting under way.
In the same tree, a skinny bonobo infant walked a few feet from its mother, then returned and clambered, wriggling, into the mother’s arms—and then did the same thing again. And there were glimpses, through branches, of other unhurried bonobos, as they scratched a knee, or glanced down at us, unimpressed, or stretched themselves out like artists’ models. Hohmann had plucked a large, rattling leaf from a forest-floor shrub that forms a key part of the bonobo diet, and he began to shred it slowly, as if eating it: bonobo researchers aim to present themselves as animals nonchalantly feeding rather than creepily stalking. He and Surbeck made solemn, urgent notes in their waterproof notebooks, and whispered to one another. They were by now aware of some twenty bonobos above us, and could identify many by name (Olga, Paulo, Camillo). A fact not emphasized in wildlife films is that ape identification is frequently done by zoomed-in inspection of genitals. A lot of the conversation at Lui Kotal’s dinner table dealt with scrotal shading or the shape of a female bonobo’s pink sexual swelling. (“This one is like chewing gum spit out,” Caroline Deimel, the Austrian, once said of a female.)
At about six-thirty, the bonobos started moving down the trees—not with monkey abandon but branch by branch, with a final thud as they dropped onto the forest floor. Then they walked away, on all fours, looking far tougher—and more lean and muscular—than any zoo bonobo. An infant lay spread-eagled on the back of its mother, in a posture that the scientific literature sweetly describes as “jockey style.” (A bonobo’s arms are shorter than a chimpanzee’s, and its back is horizontal when it walks. A chimpanzee slopes to the rear.) As the last of the bonobos strolled off, we lost sight of them: the undergrowth stopped our view at a few feet. We walked in the direction they seemed to have gone, and hoped to hear a call, or the sound of moving branches. Hohmann told me that bonobos sometimes gave away their position by flatulence. The forest was by now hot, and looked like a display captioned “SNAKES” in a natural-history museum: plants pulled at our clothes, trees crumbled to dust, and the ground gave way to mud.
We heard a sudden high screech ahead—“Whah, whah! ”—and then saw, coming back in our direction, a reddish blur immediately followed by black. We heard the gallop of hands and feet on the ground, and a squeal. Hohmann told me in a whisper that we had seen a rare thing—a bonobo in pursuit of a duiker, a tiny antelope. “We were very close to seeing hunting,” he said. “Very close.” The bonobo had lost the race, Hohmann said, but if it had laid a hand on the duiker in its first lunge the results would have been bloody. Hohmann has witnessed a number of kills, and the dismembering, nearly always by females, that follows. Bonobos start with the abdomen; they eat the intestines first, in a process that can leave a duiker alive for a long while after it has been captured.
For a purportedly peaceful animal, a bonobo can be surprisingly intemperate. Jeroen Stevens is a young Belgian biologist who has spent thousands of hours studying captive bonobos in European zoos. I met him last year at the Planckendael Zoo, near Antwerp. “I once saw five female bonobos attack a male in Apenheul, in Holland,” he said. “They were gnawing on his toes. I’d already seen bonobos with digits missing, but I’d thought they would have been bitten off like a dog would bite. But they really chew. There was flesh between their teeth. Now, that’s something to counter the idea of”—Stevens used a high, mocking voice—“ ‘Oh, I’m a bonobo, and I love everyone.’ ”
Stevens went on to recall a bonobo in the Stuttgart Zoo whose penis had been bitten off by a female. (He might also have mentioned keepers at the Columbus and San Diego zoos who both lost bits of fingers. In the latter instance, the local paper’s generous headline was “APE RETURNS FINGERTIP TO KEEPER.”) “Zoos don’t know what to do,” Stevens said. “They, too, believe that bonobos are less aggressive than chimps, which is why zoos want to have them. But, as soon as you have a group of bonobos, after a while you have this really violent aggression. I think if zoos had bonobos in big enough groups”—more like wild bonobos—“you would even see them killing.” In Stevens’s opinion, bonobos are “very tense. People usually say they’re relaxed. I find the opposite. Chimps are more laid-back. But, if I say I like chimps more than I like bonobos, my colleagues think I’m crazy.”
At Lui Kotal, not long after we had followed the bonobos for half a day, and seen a duiker run for its life, Hohmann recalled what he described as a “murder story.” A few years ago, he said, he was watching a young female bonobo sitting on a branch with its baby. A male, perhaps the father of the baby, jumped onto the branch, in apparent provocation. The female lunged at the male, which fell to the ground. Other females jumped down onto the male, in a scene of frenzied violence. “It went on for thirty minutes,” Hohmann said. “It was terribly scary. We didn’t know what was going to happen. Shrieking all the time. Just bonobos on the ground. After thirty minutes, they all went back up into the tree. It was hard to recognize them, their hair all on end and their faces changed. They were really different.” Hohmann said that he had looked closely at the scene of the attack, where the vegetation had been torn and flattened. “We saw fur, but no skin, and no blood. And he was gone.” During the following year, Hohmann and his colleagues tried to find the male, but it was not seen again. Although Hohmann has never published an account of the episode, for lack of anything but circumstantial evidence, his view is that the male bonobo suffered fatal injuries.
On another occasion, Hohmann thinks that he came close to seeing infanticide, which is also generally ruled to be beyond the bonobo’s behavioral repertoire. A newborn was taken from its mother by another female; Hohmann saw the mother a day later. This female was carrying its baby again, but the baby was dead. “Now it becomes a criminal story,” Hohmann said, in a mock-legal tone. “What could have happened? This is all we have, the facts. My story is the unknown female carried the baby but didn’t feed it and it died.” Hohmann has made only an oblique reference to this incident in print.
These tales of violence do not recast the bonobo as a brute. (Nor does new evidence, from Lui Kotal, that bonobos hunt and eat other primates.) But such accounts can be placed alongside other challenges to claims of sharp differences between bonobos and chimpanzees. For example, a study published in 2001 in the American Journal of Primatology asked, “Are Bonobos Really More Bipedal Than Chimpanzees?” The answer was no.
The bonobo of the modern popular imagination has something of the quality of a pre-scientific great ape, from the era before live specimens were widely known in Europe. An Englishman of the early eighteenth century would have had no argument with the thought of an upright ape, passing silent judgment on mankind, and driven by an uncontrolled libido. But during my conversation with Jeroen Stevens, in Belgium, he glanced into the zoo enclosure, where a number of hefty bonobos were daubing excrement on the walls, and said, “These bonobos are from Mars. There are many days when there is no sex. We’re running out of adolescents.” (As de Waal noted, the oldest bonobo in his San Diego study was about fourteen, which is young adulthood; all but one episode of oral sex there involved juveniles; these bonobos also accounted for almost all of the kissing.)
Craig Stanford, in a 1997 study that questioned various alleged bonobo-chimpanzee dichotomies, wrote, “Female bonobos do not mate more frequently or significantly less cyclically than chimpanzees.” He also reported that male chimpanzees in the wild actually copulated more often than male bonobos. De Waal is unimpressed by Stanford’s analysis. “He counted only heterosexual sex,” he told me. “But if you include all the homosexual sex then it’s actually quite different.” When I asked Hohmann about the bonobo sex at Lui Kotal, he said, “It’s nothing that really strikes me.” Certainly, he and his team observe female “g-g rubbing,” which is not seen in chimpanzees, and needs to be explained. “But does it have anything to do with sex?” Hohmann asked. “Probably not. Of course, they use the genitals, but is it erotic behavior or a greeting gesture that is completely detached from sexual behavior?”
A hug? “A hug can be highly sexual or two leaders meeting at the airport. It’s a gesture, nothing else. It depends on the context.”
At Lui Kotal, the question of dominance was also less certain than one might think. When I’d spoken to de Waal, he had said, unequivocally, that bonobo societies were dominated by females. But, in Hohmann’s cautious mind, the question is still undecided. Data from wild bonobos are still slight, and science still needs to explain the physical superiority of males: why would evolution leave that extra bulk in place, if no use was made of it? Female spotted hyenas dominate male hyenas, but they have the muscle to go with the life style (and, for good measure, penises). “Why hasn’t this levelled out in bonobos?” Hohmann asked. “Perhaps sometimes it is important” for the males to be stronger. “We haven’t seen accounts of bonobos and leopards. We don’t know what protective role males can play.” Perhaps, Hohmann went on, males exercise power in ways we cannot see: “Do the males step back and say to the females, ‘I’m not competing with you, you go ahead and eat’?” The term “male deference” has been used to describe some monkey behavior. De Waal scoffs: “Maybe the bonobo males are chivalrous! We all had a big chuckle about that.”
Hohmann mentioned a recent experiment that he had done in the Frankfurt zoo. A colony of bonobos was put on a reduced-calorie diet, for the purpose of measuring hormones in their urine at different moments in their fast. It was not a behavioral experiment, but it was hard not to notice the actions of one meek male. “This is a male that in the past has been badly mutilated by the females,” Hohmann said. “They bit off fingers and toes, and he really had a hard life.” This male had always been shut out at feeding time. Now, as his diet continued, he discovered aggression. “For the first time, he pushed away some low-ranking females,” Hohmann said. He successfully fought for food. He became bold and demanding. A single hungry animal is not a scientific sample, but the episode showed that this male’s subservience was, if not exactly a personal choice, one of at least two behavioral options.
The media still regularly ask Frans de Waal about bonobos; and he still uses the species as a stick to beat what he scorns as “veneer theory”—the thought that human morality is no more than a veneer of restraint laid over a vicious, animal core. Some of his colleagues in primatology admit to impatience with his position—and with the broader bonobo cult that flattens a complex animal into a caricature of Edenic good humor. “Frans has got all the best intentions, in all sorts of ways, but there is this sense in which this polarizing of chimps and bonobos can be taken too far,” Richard Wrangham said. Hohmann concurred: “There are certainly some points where we are in agreement; and there are other points where I say, ‘No, Frans, you should go to Lomako or Lui Kotal, and watch bonobos, and then you’d know better.’ ” He went on, “Frans enjoyed the luxury of being able to say field work is senseless. When you see wild bonobos, some things that he has emphasized and stretched are much more modest; the sex stuff, for example. But other things are even more spectacular. He hasn’t seen meat-sharing, he has never seen hunting.”
“I think Frans had free rein to say anything he wanted about bonobos for about ten years,” Stanford told me. “He’s a great scientist, but because he’s worked only in captive settings this gives you a blindered view of primates. I think he took a simplistic approach, and, because he published very widely on it and writes very nice popular books, it’s become the conventional wisdom. We had this large body of evidence on chimps, then suddenly there were these other animals that were very chimplike physically but seemed to be very different behaviorally. Instead of saying, ‘These are variations on a theme,’ it became point-counterpoint.” He added, “Scientific ideas exist in a marketplace, just as every other product does.”
At the long table in the center of the camp, I showed Hohmann the “Save the Hippie Chimps!” flyer from the Manhattan benefit. He was listening on headphones to Mozart’s Requiem; he glanced at the card, and put it to one side. Then, despite himself, he laughed and picked it up again, taking off the headphones. “Well,” he said.
We were at Lui Kotal for three weeks. “If you stay here, the hours become days, become months,” Martin Surbeck said. “It all melts.” We had two visitors: a Congolese official who, joined by a guard carrying an AK-47, walked from a town twenty-five miles away to cast an eye over the camp and accept a cash consideration. He stayed for twenty-four hours; every hour, his digital wristwatch spoke the time, in French, in a woman’s voice—“Il est deux heures.”
I saw the bonobos only one other time. I was in the forest with Brigham Whitman, one of the two bearded Americans, when we heard a burst of screeching. In a whisper, Whitman pointed out Dante, a senior male, sitting on a low branch. “He’s one of the usual suspects,” Whitman said. “Balls hanging out, that’s his pose.” Whitman ran through Dante’s distinguishing characteristics: “He’s very old—perhaps thirty—and missing most of his right index finger. His lips are cracked and his face is weathered, but his eyes are vibrant. He has large white nipples. His toes are extremely fat and huge, and his belly hair is redder.” He was the oldest male. “Dante just gets his spot and he doesn’t move. He just sits and eats.”
We followed Dante and a dozen others throughout the afternoon. They climbed down from trees, walked, and climbed back up. Small, non-stinging bees congregated in the space between our eyeballs and the lenses of our binoculars. In the late afternoon, Dante and others climbed the highest trees I had seen in the forest. It was almost dark at the forest floor, but the sun caught the tops of the trees, and Dante, a hundred and fifty feet up, gazed west, his hair looking as if he’d just taken off Darth Vader’s helmet, his expression grave.
In the lobby of the Grand Hotel in Kinshasa, the Easter display was a collection of dazed live rabbits and chicks corralled by a low white wicker fence. At an outdoor bar, the city’s diplomatic classes gave each other long-lasting handshakes while their children raced around a deep, square swimming pool. I sat with Gottfried Hohmann; we had hiked out of Lui Kotal together the day before. As we left the half-light of the forest to reach the first golden patch of savanna, and the first open sky, it had been hard not to feel evolutionary stirrings, to feel oneself speeding through an “Ascent of Man” illustration, knuckles lifting from the ground.
By the pool, Hohmann talked about a Bavarian childhood collecting lizards and reading Konrad Lorenz. He was glad to be going home. He has none of the fondness for Congo that he once had for India. Still, he will keep returning until retirement. He said that in Germany, when he eats dinner with friends who work on faster-breeding, more conveniently placed animals, “I think, Oh, they live in a different world! People say, ‘You’re still . . . ?’ I say, ‘Yes. Still.’ This big picture of the bonobo is a puzzle, with a few pieces filled, and these big white patches. This is still something that attracts me. This piece fits, this doesn’t fit, turning things around, trying to close things.”
Because of Hohmann’s disdain for premature theories, and his data-collecting earnestness, it had sometimes been possible to forget that he is still driving toward an eventual glimpse of the big picture—and that this picture includes human beings. Humans, chimpanzees, and bonobos share a common ancestor. Was this creature bonobo-like, as Hohmann suspects? Did the ancestral forest environment select for male docility, and did Homo and the chimpanzee then both dump that behavior, independently, as they evolved in less bountiful environments? The modern bonobo holds the answer, Hohmann said; in time, its behavior will start to illuminate such characteristics as relationships between men and women, the purpose of aggression, and the costs and benefits of male bonding.
At Lui Kotal, there were no rocks in the sandy earth, and the smallest pebble on a riverbed had the allure of precious metal. It is not a place for fossil hunters; the biological past is revealed only in the present. “What makes humans and nonhuman primates different?” Hohmann said. “To nail this down, you have to know how these nonhuman primates behave. We have to measure what we can see today. We can use this as a reference for the time that has passed. There will be no other way to do this. And this is what puts urgency into it: because there is no doubt that, in a hundred years, there won’t be great apes in the wild. It would be blind to look away from that. In a hundred years, the forest will be gone. We have to do it now. This forest is the very, very last stronghold. This is all we have.