Paleofantasy: What Evolution Really Tells Us about Sex, Diet, and How We Live (25 page)

In hunter-gatherer societies, by contrast, babies spend a substantial amount of time being held and cared for by someone besides their mother. They are certainly bonded to their mother and can recognize her from an early age, but they are carried around, fed (sometimes including nursing), and entertained by a variety of friends and relatives in their social group. These “alloparents”—people other than the mother who participate in child rearing—are thought to be the reason that humans can get away with weaning early and producing numerous children: exclusively maternal care is not the way that humans seem to have evolved.

In fact, when scrutinized closely, humans begin to look a bit like cooperative breeders. Say the phrase “cooperative breeder” to biologists, and their eyes light up in recognition. The same is not so true for most other people, so allow me to explain. Most animals have no parental care; the vast majority of invertebrates, as well as most fish, reptiles, and amphibians, unceremoniously dump their eggs or larvae into the environment and swim or waddle away. Even if they carefully craft a nest to safeguard the developing young, as do sea turtles, the adults are long gone by the time the babies appear.

In a number of species, however, someone, usually the mother, stays with the young until sometime after hatching. Birds feed their chicks, either by diligently ferrying worms to the nest as robins do, or by leading their young to food they can find themselves, as chickens do. In mammals, of course, maternal care is
de rigueur
, because by definition, mammals feed their young milk from the mother’s mammary glands. In both groups, sometimes dad helps out, sometimes not.

Some birds and mammals and a smattering of other species go even further, and have individuals other than the parents helping to take care of the offspring. Because the behavior was first noticed in birds, it was initially called “helping at the nest,” but once scientists found similar group rearing of young in mammals and even some fish, the more general term “cooperative breeding” became more common. In most cases, the helpers are older brothers and/or sisters who stay with their parents rather than going off to find a territory and raise a family of their own, although unrelated helpers are also observed.

Meerkats, those adorable little African animals from
The Lion King
and
Meerkat Manor
fame, provide a good example of cooperative breeding. Although they live in groups of twenty to thirty, only one pair in each group reproduces; the other members help with hunting insect prey, guarding the colony from predators, and taking care of the dominant female’s young. The latter responsibility is taken to an extreme, with the females who lack their own babies producing milk for the dominant female’s pups, as well as babysitting them. The African deserts in which meerkats live are hostile places, filled with snakes, scorpions, and other threats, and the abundance of caregivers helps ensure the survival of the pups.

The meerkat cooperative breeding system is fascinating for a number of reasons—how, for example, does the alpha female control breeding by the other females?—but for our purposes here, they are poster children for an alternative version of the family. Instead of mother and father and baby making three—or, given the usual meerkat litter size, making five or six—all the individuals in the group collaborate to raise one set of offspring. And in most cooperative breeders, including the meerkats, cooperating is the only way to go. A solitary pair of animals has very little chance of successfully raising a baby.

So, did humans evolve to be like meerkats, or more like the colobus monkeys, with their reluctance at allowing even other group members to handle their young? For many years, anthropologists and sociologists viewed the nuclear family as an essential element in human evolution, and as I discussed in Chapter 7, it was seen as the essence of our sexual behavior as well. And as far as child rearing was concerned, the mother provided all the necessary care, so long as someone went out and killed the mammoths. But increasingly, the idea that human mothers not only
can
share that care, but always have, has gained traction. In other words, humans act like cooperative breeders.

A few differences between humans and the classic vertebrate cooperative breeders are apparent, of course. Most important, in the meerkats and similarly behaving species, including birds such as the acorn woodpecker and the pied kingfisher, the helpers are forgoing their own reproduction by sticking around the familial territory. These additional individuals would be capable of breeding themselves, but for a variety of reasons they do not do so. In the meerkats and other cooperatively breeding mammals, the alpha female seems to influence the other females’ physiology via chemicals she produces that temporarily suppress their sex hormones, rendering them unable to conceive. In some other cooperative breeders, the helpers could reproduce if they had their own nests, but acceptable real estate is in short supply, leading to a situation a bit like that of adult children returning to their parents’ house after college.

In human hunter-gatherer societies, the helpers, or alloparents, are not quite so constrained; they can be siblings, grandparents, fathers, aunts, cousins, or even nonrelatives. How essential is their contribution to child rearing, and what does that level of importance suggest about the “natural” nuclear family?

Helping at the human nest

Anthropologist Sarah Blaffer Hrdy is well known for her studies of primate behavior, and while she is now most famous for her scholarly work on motherhood, she originally studied something far less beneficent: infanticide, the killing of young by other group members. In the hanuman langurs of India that she observed for many years, Hrdy discovered that a new dominant male entering the troop would try to kill the infants already present.
¹¹
This horrific behavior is not an aberration, but an evolutionary strategy that is to the male’s advantage, because a female who has lost her young will come into heat again very quickly, enabling the interloper to mate with her and increasing his fitness.

The female resists having her infant killed, but if it happens, her rapid return to sexual receptivity benefits not only the new male but her as well, since the resulting offspring will still pass on her genes. And it is this “whatever works” approach that puts the evolution of the family in a new light.

Hrdy agrees that human infants require a lot of care, and that early weaning combined with extended human childhood, even if youngsters contribute to the household, makes a mother’s job a daunting one. A human mother can have one baby at her breast and several more that still depend on her—a situation that is difficult for one person to handle alone. Who helps out? Hrdy argues that although the “sex contract” view of human evolution that I described in Chapter 7—in which men bring home meat for the family in return for a promise of sexual fidelity—implies that the father is always the other component of the family, this need not be the case.
¹²
Why not simply use whoever is available, including, but not necessarily limited to, the father of the children? In other words, why not have a form of cooperative breeding?

Hrdy suggests that human females evolved to be opportunistic in their use of others as alloparents.
¹³
Sure, dad is fine, but if he dies, disappears, or simply can’t come up with the meat that day, help from others should be perfectly acceptable, and in many parts of the world it is. Human mothers are likely to be the primary or only source of milk for very young children, but other forms of food can be provided by the rest of the group. Whether in hunter-gatherer cultures or modern industrialized societies, fathers are not reliably available, or they may not be up to the task. A harried mom seeking help from anyone who is available is not unusual or a product of a twenty-first-century life. “There is nothing evolutionarily out of the ordinary about mothers cutting corners or relying on shared care,”
¹⁴
says Hrdy. “Without alloparents, there never would have been a human species.”
¹⁵
More globally, she points out, “The needs of children outstrip what most fathers are able or willing to provide,” and hence “a mother giving birth to slow-maturing, costly young does so without being able to count on help from the father.”
¹⁶

Fathers can still be important, as I discuss later in this chapter. And Hrdy is not suggesting that we evolved in a chaotic environment of pass-the-baby, where everyone in a social group cares for the children
en masse
, in a kind of paleo kibbutz. Undeniably, human infants and their mothers form a close bond. But that bond is not, and maybe should not be, the only one that supplies the child’s needs. Anthropologists Ann Cale Kruger and Mel Konner put it this way: “It may not take a village to soothe a crying baby, but it often involves more than a mother alone, a fact that is taking on growing importance in our understanding of human evolution.”
¹⁷

Studies of children reared with multiple caregivers—again, not in an atmosphere where babysitters come and go, but one with two parents and a grandmother, or with a mother, a couple of aunts, and an older sibling—support this idea. Among the Gusii agricultural people in Kenya, children are better adjusted, more empathetic, and more independent if they had strong attachments to at least one other person besides a parent while they were growing up. Anthropologist Karen Kramer of Harvard University calculated the proportion of direct child care, defined as nursing, feeding, carrying, holding, or grooming (this last refers to activities like bathing and dressing, not fashion or makeup advice) provided by mothers, fathers, and other individuals in nine traditional societies. On average, mothers did about half the work, with the remainder parceled out among an array of relatives and unrelated group members.
¹⁸
Hrdy summarizes a series of studies of Israeli and Dutch children raised either mainly by their mothers or by mothers and other adults by saying, “Children seemed to do best when they have three secure relationships—that is, three relationships that send the clear message ‘You will be cared for no matter what.’”
¹⁹
Not one, not even two, but three. What’s more, it is the reassurance itself that is important, not the person or persons who provide it.

Mothers, of course, often benefit from multiple caregivers themselves, in the form of increased child survival. An examination of eight traditional and modern societies by Ruth Mace and Rebecca Sear showed that having grandmothers who helped care for their grandchildren nearly always meant a greater likelihood of the children living to adulthood.
²⁰
Similarly, Kramer found that the presence of alloparents in at least a dozen traditional societies meant better survival and growth of the children, as well as mothers who gave birth more frequently.
²¹
Kramer cautions, however, that the effect of these helpers is complicated by sharing of food and labor that goes on in the social group, apart from caring for the child per se; unlike the meerkats, of course, humans do not have a single breeding pair in isolation, so it is more difficult to separate the effects of alloparents’ care from the general benefits of living in a social group.

A somewhat more skeptical view is taken by Beverly Strassmann of the University of Michigan, who has studied the Dogon people of Mali for over twenty-five years. The Dogon farm pearl millet and live in cliff-side villages with a close network of relatives. Although most men have a single wife, polygyny is accepted, and women have an average of ten surviving children. Most of the child care is performed by women and girls, with girls between the ages of five and nine often caring for their siblings.

Strassmann looked at child mortality, as did Kramer, but reported a very different picture. Among the Dogon, being in a kin group that extended beyond the nuclear family meant that a child was less likely to survive, not more—a pattern Strassmann attributed to increased competition for food and other resources.
²²
In families with multiple wives, children grew more slowly and were more likely to die than in monogamous households. The grandmothers that were so helpful in Mace and Sears’s study were viewed by the Dogon as a drain on society, although older women actually worked harder than older men.

Strassmann suggests that these dire findings result from parents and other relatives coercing children to work, so that what might superficially appear to be cooperation is actually forced labor. In addition, the aforementioned competition among siblings for limited food means that larger families will be harder on the smaller, weaker members. Finally, if men wield most or all of the political power, they can manipulate family life to their benefit and obviate any attempts at cooperation.

Calling all fathers, and grandmothers, and possibly aunts

To help resolve the disparity between the Dogon’s situation and that of other traditional societies, as well as, perhaps, the ancestral human family, we need to look more closely at who exactly those alloparents might be. First, the most obvious supplement to a mother’s care: the father. Although fathers cross-culturally tend to do little in the way of direct child care, exceptions do occur, most notably in the Aka foraging people of central Africa. Aka fathers spend more than half the day “within arm’s reach of their one- to four-month-old babies,” according to Hrdy,
²³
and will often take children and even infants along on hunting expeditions. Significantly, hunter-gatherer fathers spend much more time with babies than do fathers from agricultural societies, with dads from Western societies somewhere in the middle. Perhaps the Dogon, with their agricultural lifestyle, lack the paternal help that some of the other groups with cooperative child rearing possessed.

Fathers sometimes get short shrift when it comes to involved parenting, but new research is suggesting that they might be underestimated. Conventional wisdom holds that men are unreliable long-term mates—and need to be bribed with sexual fidelity—because to them, mate competition is more important than child care. Hence, males were thought to benefit more by playing the field than by helping with the kids. But what if the urge to find a new mate is ameliorated by the experience of fatherhood itself?