The largely terrestrial langurs, relatively easily observed, especially in and around the urban areas of India and other Asian cities, have been a subject of serious scientific study as far back as 1834. They also became a growing focus of research and debate because of their disturbing behavior. Unremarkable in many ways among the vast species of primates, scientists and residents who shared the monkeys’ living areas were shocked to witness infanticide by the animals. The observation threatened to shatter a myth about ourselves and other animals—that humans are the only creatures who murder members of their own species. The langur killings were so startling to witnesses, and so difficult to explain, that they were generally dismissed by researchers who initially described them as aberrant behavior without any logical explanation. Even mere fighting among adult males was dismissed as “bizarre, certainly not typical, behavior,” by researcher Phyllis Jay in a 1963 study.3 Some scientists attributed witnessed langur infanticide to the stresses and “social pathology” of overpopulation, likely linked at least in part to their urban living situations that recalled a classic early study by John Calhoun conducted for the National Institute of Health. In his now-famous experiments, Calhoun allowed a population of confined rats to grow until the jam-packed animals began to express what he called a “behavioral sink” of activities with a range of pathological behaviors, including infanticide and cannibalism.4
Hrdy first heard of the langur infanticides in a popular undergraduate class on primate behavior, taught by anthropologist and evolutionary biologist Irven DeVore. When Hrdy attended Harvard to pursue a doctorate in anthropology, she came back to the puzzle of adult langur violence against infants. Her first graduate paper, “Infant-Biting and Deserting among Langurs,” in a class about the evolution of sex differences, failed to convince an important reader. The teaching assistant who graded her paper wrote that it had “nothing to do with sex,” she recalled later in her book.5 But before Hrdy earned her doctorate, she would begin to make a powerful case that violence had almost everything to do with sex. She would end up exploding traditional theories on sex, gender, violence, and parenting with a revolutionary perception that deadly violence against offspring could, surprisingly, serve an evolutionary goal, and was fueled by the powerful drive of competition for mates explained in Darwin’s classic theory of selection. The idea that infanticidal behavior might be adaptive for the perpetrators rather than an aberration provided a seminal insight that would help galvanize a growing body of research seeking to understand domestic violence by human males.
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The lushly forested hills of Mount Abu rise from the worn plains of Rajasthan in northern India, some 455 miles southwest of Delhi. The key hilltop town is Abu, nestled next to Lake Nakhi, where the community’s population of 8,000 swells at various times with tourists and pilgrims who make the trek to the area’s sacred caves and the twelfth-century Hindu temple of Dilwara. Langur activity in Abu and the surrounding region was Hrdy’s focus during 1,500 hours of research in five visits during different seasons from 1971 to 1975, when she tracked the behavior of dozens of langurs in seven different troops. Langur bisexual troops are relatively stable bands of females and their offspring, usually headed by a succession of lone males, whose reigns are challenged or usurped by other single males. Young, weaned males, or “sub adults,” are typically ejected from the troops by the king male to find their own way, either to eventually attempt to head another troop, or cruise the region with bands of “extratroop” males, which may sometimes include immature females without young.
By 1975 Hrdy’s study included 242 langurs living in either breeding bands or with extratroop males. She focused on a subset of individually identified langurs that lived in seven troops, which she named Arbuda Devi Temple, Bazaar, Hillside, Chippaberi, I. P. S., Toad Rock, and School, after their territories. Her troops had different levels of human interaction. The Chippaberi and Bazaar troops obtained a “substantial” portion of their daily food from humans—either scavenged by the animals, or, in the case of the Chippaberi troop, fed chickpeas, peanuts, and chapatti directly by travelers at nearby bus stops, she noted in The Langurs of Abu. Others obtained less food from humans, but most had some human contact. Like Jane Goodall, Hrdy named the langurs for noticeable physical characteristics—such as Splitear, Harelip, Cast-eye, T. T. (for “Tied Tail”), Elfin (for her pointed ears), and Pawlet (for a deformed right paw)—rather than as a collection of numbers or letters.
She wasn’t particularly taken with the individual daily habits of the creatures, but was fascinated by their interactions. “I am no true naturalist,” she remarked in her book. “It was the high drama of their lives, the next episode of the Colobine soap opera that got me out of bed in the morning and kept me out under the Indian sun, tramping about their haunts for eleven hours at a stretch.”6
Although Hrdy had traveled to India expressly to witness and try to tease out why adult male langurs were killing infants, over time she expanded her study to include an examination of female, as well as male, “reproductive strategies.” But when she finally encountered the violence that she had hoped to see, it was so shocking that Hrdy initially had a tough time coming to grips with it.
“Although infanticide was foremost on my mind when I decided to study langurs, its actual occurrence seemed totally implausible,” she writes in The Langurs of Abu.7 Even though the Hillside troop’s dominant male had been ousted by another, “despite the fact that all six infants were missing, despite reports by two local people who had seen an adult male langur kill infants in the Hillside troop’s home range, I grasped at straws,” Hrdy confessed in the book. “I spent a whole day trying to convince myself that this was a different troop, one without infants, which had somehow materialized out of the torrential rains and thick mist of that monsoon month. But the longer I peered through the mist at those rain-soaked, skittish females, the more I realized they were, unmistakably, Bilgay, Itch, Harrieta, Oedipa, Pawless, and Sol. The seventh female and the six infants were never seen again.”
Hrdy gradually came to terms with the infanticides and eventually reached the startling conclusion that not only were the killings not unusual at Abu, and, according to reports, at nearby Dharwari and Jodhpur as well, but they were, in fact, routine after an alpha male was ousted by another. In the Abu region, infanticides by males turned out to be the “single greatest cause of mortality,” Hrdy discovered.8 Infant deaths varied among the troops she observed, from almost none in Toad Rock where the troop was ruled for a significant period of time by the same male, to an astounding 83 percent during a period in the Hillside troop when the alpha male changed three times. The females in Hillside were subjected to a particularly thankless task of birthing and rearing young before their offspring were killed due to a revolving door of males in their lives. When Hrdy first began observing the Hillside troop, it was ruled by Mug, who had taken over from Shifty Leftless and methodically destroyed Shifty’s offspring before impregnating the females to populate the troop with his own young. Shifty later returned to oust Mug, destroying Mug’s young in turn. But as Shifty attempted to dominate both Hillside and the nearby Bazaar troop, Mug took advantage of Shifty’s absences to again take over Hillside and start the infant killings over again, confronting once more his former paramour Itch.
The cycles of infanticide were the catalyst for a theory by Hrdy that would revolutionize perceptions about adult langur violence against the young. Hrdy argued that the killings were far from an aberration. Instead, they could be expected when a new male took over a troop. Infanticide was a priority for usurping males who had driven out an old leader. The ousted male’s offspring were quickly dispatched. The females fled or banded together to protect their offspring as long as they could. The infants had few protective resources other than clinging to their mothers, and usually didn’t survive for very long, Hrdy noted. Mothers tended to stave off the inevitable for only a limited period. They were hunted by the males out to destroy their i
nfants. Some mothers quickly lost their young to the murderous new leader, some mothers vanished. But some also weaned their young early, speeding up the time they would come into estrous again and mate with the new male. Others still with young might come into a “false estrous” and mate. In cases Hrdy observed where females still with young quickly mated or became pregnant, “leftover” young from a previous male were usually allowed to survive by the new leaders, apparently confused about the paternity of the offspring of females they were mounting.
In Hrdy’s analysis, the infanticides were part of a clear strategy for male access to females and served the goal of evolutionary fitness, or reproductive success, for a troop’s new dominant male. Male langurs tend to have a small window of opportunity to procreate and add their own genes to the langur pool before they’re ousted by another younger, stronger, challenging male and relegated to the community of lower-ranked males whose chances at procreation are significantly reduced if not eliminated. Dominating a troop is a langur’s drive for a kind of monkey immortality, at least for a male’s genes. The killing of progeny of previous leaders serves to make the world safer for themselves and their own infants, and helps to ensure the evolutionary fitness of their offspring, who would be more likely to procreate themselves in a world where more rivals are eliminated. By killing infants, males also ensure that mothers come into estrous quickly for new mating, and their nurturing resources are immediately freed to tend to the new males’ offspring. Because male langur domination of a troop can be relatively short-lived, leaders can’t waste time waiting for existing offspring to grow and become independent before adult females become willing sex partners and new mothers for their own baby langurs. Of course, none of this goes through a langur male’s mind when he kills an infant in his new troop; all he cares about is mounting a female, and she won’t be in the mood if she has a baby clinging to her belly.
Hrdy’s perspective rocked the study of the social, sexual, and parental relationships among langurs and sparked a fresh look at and analysis of infanticides not only of the primates but also among other species. The process Hrdy discerned involved a brutally pragmatic behavior linked, however unconsciously by the langurs, to an evolutionary cost-benefit drive. It was immediately controversial, and not a little disturbing to humans whose self-image as generous, caring adults and parents didn’t fare so well in the bloody reflection of animals close to us on the evolutionary ladder. It was tough for many anthropologists to swallow. One critic sniped at the time that Hrdy’s monkeys were deranged. A male colleague recommended she spend more time raising her own children, managing at the same time to highlight our possible links to Neanderthals. Despite the attacks, Hrdy’s theory would soon become the orthodoxy of anthropologists and biologists as researchers began recording the same system of infanticides among several species. Hrdy’s work is a stark example of how a reality can exist for decades yet remain unknown simply because scientists have not recognized it. While a long list of researchers had failed to make sense of langur infanticide, Hrdy’s focus on the female position in langur troops and sensitivity to reproductive strategies led her to a startling, remarkable insight that soon became an accepted principal of animal science.
Several researchers before Hrdy had viewed langur and other primate societies as almost idyllic communities in which each individual did its bit to help ensure the survival of as many members of its own species as possible. Young male vervet monkeys who hung around the periphery of troops, for example, were even seen by some researchers as placing themselves as willing “buffer” primate sacrifices to predators stalking a troop to protect the more valuable members. “Not surprisingly,” wrote Hrdy in Langurs of Abu, “when we first began to intensively study our closest nonhuman relatives, the monkeys and the apes, an idealization of our own society was extended to theirs.”9 Monkeys, like humans, appeared to “maintain complex social systems geared towards ensuring the group’s survival,” wrote Hrdy, convinced that the perception of such societies was more wish fulfillment than science. In a much later book, Mother Nature, Hrdy pointed out that, as a mother of three in the modern world, she’s “partial” to a “companionate monogamous marriage” as the most satisfying for her and the most beneficial for her children.10 Yet, she admits, that’s not necessarily the case for primates, early man, nor even for modern human moms in different situations. “It would scarcely be wise, or fair, to extrapolate my self-interested priorities to them,” she adds, referring to early mothers. “Nevertheless, from Victorian times to the present, this is what many anthropologists and evolutionists have done.”
Far from the idealized visions of primate societies popular at the time she made her discovery, Hrdy realized that an individual’s drive toward evolutionary fitness could be so selfish that it could even potentially threaten the survival of a community of langurs, such as in the Hillside troop, whose population was decimated by mass baby murder.
Righting idealized misconceptions in theories about primates and early man is critical because it promises to help us more effectively understand some of our own drives, Hrdy argued in The Langurs of Abu. It is exactly our “peculiar misconception about ourselves, and about primates, that lends the history of langur studies its significance,” Hrdy wrote.11 “By revealing our misconceptions about other primates, the langur saga may unmask misconceptions about ourselves.”
If langurs provide an insight into human community, it’s clearly not a touchy-feely vision of male baby love—nor does it argue for an easy relationship between the sexes, whose evolutionary interests are so disparate they’re almost “two different species,” Hrdy noted.12 Rarely, she wrote, “do the best interests of the female langur coincide” with those of her consort. “Sexuality means conflict,” Hrdy matter-of-factly added, quoting playwright August Strindberg. “Apart from insemination, langur females have little use for males except to protect them from other males.”
Other scientists intrigued by Hrdy’s research and analysis began to look out for, and record, a system of infanticide by males—and some by domineering females—among several other species, particularly among the Colobine subfamily of primates. Similar behavior is also well known today among lions, wild dogs, rhinos, mice, ducks, hippos, bears, rats, rabbits, and wolves, among scores of other species.
Within a few short years after Hrdy developed her theory, other primate researchers were witnessing infanticides with increasing frequency. Silverback gorillas, perhaps most notably observed by primatologist Dian Fossey, can be attentive fathers, and may even take over care for their young in cases of maternal death or rare desertion. Imposing, long-living silverbacks have an advantage of being in charge of a troop for extended periods of time, sometimes up to 30 years, so they don’t have to deal with frequent challenges to their dominance. Nevertheless, Fossey alone documented nine cases of infanticide of offspring of a rival male.13
After studying chimpanzees in Tanzania’s Gombe Park for ten years, Jane Goodall witnessed her first infanticide—but this time, it was by a mother and daughter team of chimps Goodall had named Passion and Pom. The pair hunted down and killed at least five (possibly as many as eight) infants of rival females in their troop by biting them in the neck—and then eating them. The “barbarous murders” so appalled Goodall that she very unscientifically chased the deadly duo away in the middle of one attempted infant-kill mission by yelling.14 The killings stopped when Pom had a baby, whom Goodall named Pax. But Goodall was unnerved by what she had witnessed, and it rattled her view of pleasant chimp life as an idealized view of a simpler, pre-human parenting and community. “I had believed . . . that the Gombe chimpanzees were, for the most part, rather nicer than human beings. Then, suddenly, we found that chimpanzees could be brutal—that they, like us, had a dark side to their nature,” she noted later in her book Reason for Hope: A Spiritual Journey.15 The infanticide she witnessed rattled her view of the essential nature of chimps—and man—and she recognized for the first time that human capacity for ag
gression and violence was as deeply rooted in our evolutionary past as our ability for cooperation and compassion. It was a lesson many didn’t want to learn. When she first published her findings in “Life and Death at Gombe” in National Geographic in 1979, the magazine was attacked for the graphic description and photos of the killings. Again, the behavior was viewed as aberrant, just as the langur killings were initially regarded, and Goodall’s eyewitness accounts were criticized as merely “anecdotal,” she recounts.16 This was “patently absurd,” Goodall wrote. “We had watched, at close range, not just one but five brutal attacks. Even more significantly, other field researchers had observed similar aggressive territorial behaviors in other parts of the chimpanzees’ range across Africa.”
Goodall continued her research into infanticide by females, which she determined was fueled by an evolutionary drive similar to males. Higher-ranking chimp females, similar to Pom and her daughter, were witnessed in several cases killing the young of rival females at a time when the offspring could be easily dispatched and before they could pose any threat to a ranking female’s young, whose own evolutionary fitness would be bolstered by the elimination of rivals.
Killer Dads Page 5
