Mothers and Others

by Sarah Blaffer Hrdy

  If there are too many possible fathers, or if a mother is deemed too promiscuous, men will be discouraged from helping her, and she will be out of luck. Nevertheless, among the Ache and the Bari (the two tribes for which we have the best data), children with two designated “fathers” were better fed and on average more likely to survive, making two seem like the optimal number of fathers under these social and ecological conditions.46

  Belief in partible paternity and other customs that facilitate maternal manipulation of information about paternity tend to be more feasible in groups with long-standing matrilineal traditions where sexual attitudes and childcare options are already tilted in favor of maternal interests. Such mindsets are very different from those in Western society, where a long history of patrilineally transmitted resources leaves men preoccupied with genetic paternity and puts children whose paternity is in doubt at a serious disadvantage. But in partible-paternity societies, where relying on a single father is an even bigger than usual gamble, having several possible fathers has the opposite effect.

  It is presumably with the ultimate goal of promoting child survival under perilous conditions that customary rituals among South American tribes like the Canela or the Kulina provide publicly sanctioned ways for mothers to pick up an extramarital provisioner.47 When they find themselves “hungry for meat,” Kulina women order men to go hunting. On their return, each woman selects a hunter other than her own husband as a partner. “At the end of the day the men return in a group to the village, where the adult women form a large semicircle and sing erotically provocative songs . . . asking for their ‘meat.’ The men drop their catch in a large pile in the middle of the semicircle, often hurling it down with dramatic gestures and smug smiles, after which the women scramble to grab a good sized portion. After cooking the meat and eating, each woman retires with the man whom she selected as her partner for the sexual tryst.”48

  Through regularly enacted rituals where sex is used to forge bonds with multiple partners, virtually every Kulina child is guaranteed more than one father. Through ritual sex, a mother lines up extra provisions for both herself and the child while at the same time taking out insurance lest her current husband default or die. “Extra” fathers are socially recognized and expected to observe the same dietary restrictions around the time of the birth as the mother’s official husband does. Nevertheless, as a matter of prudence and a courtesy to the husband, extra fathers, who have their own complex web of liaisons, are expected to be discreet.49

  CULTURALLY PRODUCED CHIMERAS

  It is vanishingly rare for any ape to produce litters or twin sets sired by different males the way lions, cheetahs, wild dogs, prairie dogs, and voles do. Over millions of years, these species have had ample opportunities to evolve uterine and ovulatory quirks that spread genetic paternity among several males, but this is not the case for apes. Thus, humans do not ordinarily produce multi-fathered twin sets, much less chimeric young who combine several male gene lines within a single individual, adding bits and pieces of extra fathers in the way cooperatively breeding marmosets do. Human twinning is unusual, and only 8 percent or so of human twins and 21 percent of triplets exhibit even low levels of chimerism; human twins with completely different fathers are exceedingly rare.50

  As relative newcomers to the cooperative breeding scene, humans have been left to extract help from extra males by other means. Solutions to this persistent posterity problem are culturally rather than biologically transmitted. In parts of the world where one father was unlikely to suffice, lineages that invented and retained beliefs about partible paternity proved best adapted to persist and so pass on these customs to subsequent generations. People have converged upon ideological solutions functionally similar to the physiological solutions that in other cooperatively breeding animals evolved through natural selection. Without actually producing genetic chimeras, women give birth to children that men believe to be chimeras.

  Chimeric paternity is an alien concept to Westerners. Our ideas about what it means to be a father have been shaped not only by our evolutionary history but by hundreds of years of patrilineal social history, not to mention scientific advances in the understanding of genetics. The recent “gening of America” has brought with it new markets as well as inventions, including new DNA paternity test kits.51 Whether or not accurate information about paternity is a good idea depends on who is asking. Is it a man who feels duped? A mother who feels entitled to more support? A grown child seeking his or her identity? Or is it a growing child who needs a lot of care, regardless of who provides it?

  When I consider how unprecedented actual knowledge about paternity is, and when I start to worry about how it is likely to affect the well-being of children, I am reminded of the long-ago Naskapi tribesman who was taken to task by an early Jesuit missionary in North America. Seeing the priest’s dismay at the group’s sexual promiscuity and uncertain paternity, the man responded: “Thou hast no sense. You French people love your own children; but we love all the children of our tribe.”52 Spoken like a true cooperative breeder.

  THE MIXED MOTIVES OF MEN

  All primate males are interested when they perceive that another male is having sex with a female in their group, and they exhibit various degrees of agitation. It is scarcely surprising that most Darwinians, including Darwin himself, took for granted that “our early semi-human ancestors” could not have practiced polyandry because there is no way a male could ever be “so devoid of sexual jealousy” or be willing to invest in children whose paternity he was less than certain of.53

  There is no denying the potentially disruptive effects of infidelity or the power of nepotistic impulses. Men with the option to choose between putative genetic offspring and stepchildren are likely to spend more time with the former. Among the Hadza, their ethic of communal meat-sharing notwithstanding, Marlowe found that men with biological children in camp seemed more motivated to hunt and also more inclined to channel extra meat to children they believed they had actually sired. The one stepchild in Marlowe’s sample who fared unusually well was also a nephew, the child of a deceased brother whose mother the hunter had married.54 Marlowe’s account is especially pertinent because in foraging contexts the majority of children alloparents provision are likely to be cousins, nephews, and nieces rather than unrelated children. It is also consistent with new research showing how adept both nonhuman and human primate males are at gauging possible paternity.

  As is the case with many primates, savanna baboon females go out of their way to mate with multiple males. Only males who have never mated with the mother, and thus can be certain at least of their nonpaternity, are potentially infanticidal. Males who have mated with the mother, by contrast, are more likely to single out her subsequently born offspring for special protection.55 But while male estimations of paternity are fairly good, they are never perfect. Thus, baboon infants often find themselves with more than one male protector even though (baboons not being marmosets) they only have one actual progenitor.

  As they mature, young baboons continue to benefit from the support of their mother’s former consorts. Among the baboons at Amboseli, Kenya—arguably the best-studied primates on earth—researchers working with Jeanne Altmann are zeroing in on some of the long-term benefits of paternal attention. In the case of daughters, the presence of their genetic father in the same troop is correlated with a faster rate of maturation. This means that a daughter with her dad nearby will begin to reproduce at an earlier age, enhancing her chances of higher overall lifetime reproductive success. Sons with a father present also mature faster, but only if their father was high-ranking at the time of their birth and presumably dominant to other males who might challenge him. The father’s rank matters less in a daughter’s case because even the lowest-ranking male would be dominant to all females in the troop who might harass or challenge her.56

  No one knows yet exactly what cues are involved, but men as well as baboons are pretty good at assessing whether or not they ac
tually sired children attributed to them. When the anthropologist Kermyt Anderson set out to analyze rates of misattributed paternity in different groups from around the world, he divided people into two categories. One contained putative fathers who felt sufficiently uncertain about paternity to demand a DNA test on their child. The other group was composed of men with no reason to doubt their paternity but who for some reason got tested. Actual rates of nonpaternity were far higher in the first group (around 30 percent) than in the second (2–3 percent).57 Presumably, male sensibilities are as good as they are precisely because at some level paternity does matter. But this does not mean that primate males only nurture young whom they are sure they have sired. So long as care is neither too exclusive nor too costly, being certain of paternity is just one of several factors that affect whether or not males protect, provision, babysit, or love children.

  Later in this chapter, I consider some of the other factors that affect the nurturing tendencies of males. In addition to protective responses toward infants in the group at large or targeted toward those born to recent consorts, or males’ concern for “reputation” and their eagerness to display what good fathers they would be, some of the most important factors involve the male’s past experience with a particular infant. A fixation with genetic paternity obscures the full range of emotions and motives that influence nurturing tendencies in men, and may also obscure their impacts on child survival. This holds true for other animals as well, as we will see in Chapter 6. Nevertheless, the unreliability and contingent nature of men’s nurturing responses raises a perplexing theoretical question: How can something so potentially important vary so much? Let me address that question first, before turning to specific mechanisms involved in nurturing impulses.

  THE PARADOX OF FACULTATIVE FATHERING

  To put men in perspective, step back for a moment and consider paternal behavior in broad comparative perspective, across all 5,400 or so species of mammals in the world. In the majority of them, fathers do remarkably little beyond stake out territories, compete with other males, and mate with females. With outlandish auditory and visual displays which often entail specially evolved weaponry, bellowing, barking, or roaring, males engage in fierce contests to rout their competitors. Then “Slam, bam, thank you ma’am” and the inseminator is off. Male caretaking is found in only a fraction of mammals. By comparison, males in the order Primates stand out as paragons of nurturing, unusual for how much protection and even direct care of young they provide.

  In the vast majority of primates, males remain year-round in the same group as females with whom they have mated. Even in species where males do not directly care for infants, males play a generalized role in the protection of young. They remain in the vicinity of the mothers, jealously protecting access to local resources (including once and future mates), and in the process males keep infants they might have sired from being attacked by rival males. Since lactation lasts a long time in primates, the incentive for would-be progenitors to eliminate infants sired by another male is enormous. By destroying unweaned infants and reducing the amount of time until the no-longer-lactating mother becomes fertile again, a newcomer can improve his chances of breeding during the limited period he is likely to have reproductive access to her. Ironically, the same prolonged dependence that makes extra help so beneficial to mothers renders infants especially vulnerable to this particularly ruthless form of male-male competition.58

  There is almost no direct male care in apes. Orangutan and chimpanzee fathers spend little, if any, time in the vicinity of their young, while contact between gorilla and bonobo fathers and their babies is limited to just being nearby. After birth, a mother gorilla may seek out her group’s protective alpha and attempt to stay close to this silverback. Once her infant is mobile, the youngster may follow his mother’s example by staying near his father, as this older infant gorilla is doing, but males do not hold or carry infants, and never provision them or their mothers. (© A. H. Harcourt/AnthroPhoto)

  Generalized protection of young is widespread, and in many species male attentions go beyond that to include staying near to and looking out for specific infants, the way some baboon males do, as well as more direct care (carrying, retrieving, huddling with infants to keep them warm) in perhaps as many as 40 percent of all primate species. Extensive male care seems especially likely to have evolved in prosimians and New World monkeys, and males in the genera Aotus and Callicebus actually provision their young.59 As primates go, then, the nurturing behaviors exhibited by some men are not particularly unusual. As Great Apes go, however, direct male care is very unusual indeed.

  Over the 70 million years that primates have been evolving, what mothers most needed from males was protection of their young from other males. Yet given that primate males remained year-round in the vicinity of mothers and infants anyway, there were myriad opportunities for selection to favor fathers inclined to do a bit more than just protect. This led to the evolution of male behaviors that range from occasional babysitting by baboons (who literally sit near the baby) to the nearly obligate male care (meaning that infants don’t survive without it) exhibited in various titi monkeys, night monkeys, and marmosets of South America. In our own species, fathers, although often helpful, are not nearly so predictable.

  While some men exhibit a marmosetlike devotion to their young and do so for a far longer time span than any other primates, other men ignore their children’s very existence. Pondering this state of affairs, I have sometimes asked myself whether there might be different morphs of men. Regardless of whether or not this is so (and there is no science of the subject, nor any way I know to tell ahead of time, for readers who might be wondering), what we do know is that nurturing responses in human fathers are extremely facultative—that is, situation-dependent and expressed only under certain conditions. This generalization holds true whether we consider provisioning or the observable intimacies between father and child.

  Overall, the frequency of father-child interactions is higher in the case of foraging peoples than among agricultural, pastoral, or most postindustrial societies. This tells us something important about both the history of our species and the different component parts involved in the evolution of paternal commitment.60 Like other mammals with a lot of male care, men are physiologically altered just from spending time in intimate association with pregnant mothers and new babies. To me, this implies that care by males has been an integral part of human adaptations for a long time. Male nurturing potentials are there, encoded in the DNA of our species. Yet unlike other mammals with extremely costly young and nearly obligate biparental care, human males may nurture young a little, a lot, or not at all. Compared with a titi monkey male, whose top priority in all the world is to remain close to any baby produced by his mate, or to a bare-faced marmoset, who vies with his mate to be the first to grab babies emerging from her birth canal so as to gobble up the hormone-rich placenta, men’s priorities are nowhere near so single-minded. Mating with a man hardwired to help rear young, even young almost certainly his, is not a trait human mothers can realistically count on.

  Some primates exhibit very high levels of direct male care, others do so only in emergencies, while still others exhibit no care at all. But the extent of this between-species variation pales when compared with the tremendous variation found within the single species Homo sapiens. Contributions of material or emotional support range from semen only to the obsessive devotion of a Mrs. Doubtfire, where a father will go to almost any lengths to remain close to his children. Across cultures and between individuals, more variation exists in the form and extent of paternal investment in humans than in all other primates combined.

  It is an understatement to say that men’s emotions in this respect are complex. Communal ideals and quests for local prestige are important. So is sexual access to women. Then there is the personal affection or the nepotistic urges men may feel, emotions which can trump communal values. But at the end of the day, we are still left with a per
plexing paradox: If men’s investment in children is so important, why hasn’t natural selection produced fathers as single-minded and devoted to childcare as titi monkeys, California mice, or dwarf hamsters? And given that male care is so idiosyncratically and contingently expressed, how could natural selection have favored human mothers who invariably produced offspring beyond their means to rear alone? How can it be that some men tenderly care for children who might not even be theirs, while other fathers certain of their paternity feel no compulsion to care at all?

  It’s time to consider some specific cases. Even though individuals vary in how affectionate they are, most anthropologists would agree that as groups go, men among people like the Aka are unusually involved in infant care. Let’s consider why.

  Both Aka parents are more or less equally responsible for provisioning children, and women as well as men participate in communal net-hunting. Aka fathers spend a lot of time in camp, and they remain within eyesight of babies a whopping 88 percent of the time. This is the highest average figure for paternal proximity recorded for any human society.61 The Aka case supports Barry Hewlett’s argument that time spent in proximity is a very important factor. Proximity provides opportunities for the nurturing potentials present in many (all?) men to be activated and tapped. Men who spend a lot of leisure time in camp have more opportunities for positive or even intimate interactions.62 But where parents live, and who else is around, can also be important. Courtney Meehan, a Washington State University anthropologist, decided to learn precisely how important.

  Whether or not female primates reside among familiar matrilineal kin is an important factor influencing whether they will accept offers of childcare assistance. But among African hunter-gatherers, individuals are unusually flexible and opportunistic, often moving many times over the course of their adult lives, visiting family and gravitating toward locally available resources, including not just material resources but good childcare. At any given point in time, mothers may have more or fewer matrilineal kin at hand. This was the situation among the Aka that Meehan studied. Mothers rarely remained in the same group their whole lives. This provided Meehan with a natural experiment for comparing how much care children received depending on whether parents lived either with the mother’s kin or with the father’s.