What Mother Nature Teaches Us About Motherhood

By Jeffrey Kluger

With squalling infants in tow, she works back-breaking shifts--as long as 17 hours a day--to feed her growing family. Then she drags herself home, where she is greeted by her equally demanding older children, who expect her to referee their squabbles as they roughhouse and play. When the kids finally fall asleep, she has only a few hours to eat, clean up and grab some shut-eye before the sun rises and she must do it all again.

Typical working mom? No, a wild baboon living on the plains of Kenya. But in ways that are deeper and more resonant than most people realize, female baboons and other nonhuman primates are typical working moms. They struggle with the same challenges that human mothers face and work out surprisingly similar solutions. Tamarin mothers in the Amazon Basin rely on aunts and grandmothers to tend the young while the mothers forage for food. Moms and dads among Brazil's titi monkeys take turns minding the kids and bringing home the bacon, just as in any well-adjusted two-income human family.

And it is not just primates whose parenting strategies echo our own. More and more, scientists have come to realize that among creatures as diverse as mice and seals, birds and spiders, mothering is a surprisingly consistent, remarkably familiar business. If there is a Mother's Day message in all this, it's that the more we understand the animals' behavior, the better we can understand our own.

For scientists studying the business of parenting, parting the curtain on the animal world helps explain not only how mothering strategies work but also how they sometimes break down. Confused teens aren't the only mothers who abandon their babies; other mammals do it too. Parents may recoil when a Susan Smith drowns her sons in a South Carolina pond, but scientists routinely observe infanticidal animals--apparently driven by similarly dark demons--committing similarly black acts.

Certainly, not everyone is pleased with this new research. Looking to animals to study something as complex as motherhood, critics say, is little more than anthropology by analogy, relying on the worst kind of scientific reductionism to explain the highest kind of human impulses. But anthropologists view matters differently, seeing in animal and human mothers a striking commonness of purpose--and a striking commonness of grace. "All mothers face similar dilemmas," says anthropologist Sarah Blaffer Hrdy of the University of California at Davis, "no matter what their ambitions or circumstances."

There are few challenges the animal families of Africa or the Amazon face that the Banzer family of Houston, wouldn't understand. Stephanie Banzer, 31, is a marketing manager for Compaq Computers as well as the mother of 19-month-old Matthew. When Stephanie gave birth, she and her husband knew they would need her income to keep the household running. Full-time mothering was thus not an option--and full-time baby-sitters were too expensive. Instead, she turned to a team of child-care providers she knew could do the job: her mother and two aunts. The three older women look after Matthew when Banzer and her husband are at work, returning the toddler well cared for at the end of the day. "These are the women who raised me," Banzer says. "He is in very loving hands."

While the Banzers may think of the work Matthew's grandmother and great-aunts do as mere baby-sitting, anthropologists know it is part of a far more primal practice called alloparenting. In all manner of animals, including bees, elephants, lions, lemurs, bats and birds, creatures with no parental investment in offspring routinely expend enormous amounts of energy caring for their relatives' young. Alloparents are not unconditional caretakers; they won't devote scarce resources to other offspring at the expense of their own. But when conditions allow an alloparenting deal to be made, it's a good bargain all around, with adults protecting their genetic legacy and the infant getting a team of surrogate moms in return. "Babies can learn to be quite satisfied with any of a select group of caretakers," says Hrdy, whose book Mother Nature is the most notable and artful of a flock of new studies re-examining motherhood.

Of course, even with a parade of alloparents, offspring will have little chance of reaching maturity if there isn't sufficient food to keep them nourished. In the game of survival, there is nothing more critical than keeping babies' bellies full, and mothers go to great lengths to get the job done. After one type of Australian spider lays her eggs, she lives barely long enough to see her young mature. Then she positions herself among them and slowly liquefies, transforming herself into an edible goo that gives her babies a nutritional kick start in life. The very idea of mammalian metabolism is a subtler case of maternal self-sacrifice. An organism taking in precious calories and then giving them away in the form of milk directly defies the me-first rule of all animal survival, yet mammal mothers do it willingly.

Often animals don't have to go to such nurturing extremes. For all creatures, one key to successful parenting is not merely reproducing but also knowing when not to reproduce--timing births so that the supply of food and other resources stay ahead of the babies to tend.

Heather Knotts, 35, of Chicago, a career mom, walks just this kind of parenting tightrope. Holding down a demanding job in an advertising agency, she works even harder at home, rearing a daughter, 5, and a son, 2. If Knotts and her husband had their way, she would set aside being adwoman and work full time as a mom. That was what they had planned. "After our first child was born, we knew I'd have to keep working," she says, "but we thought it would be for only a couple of years."

Three years after the Knottses had their first child, however, the second came along, and the idea of halving the household income while doubling the number of children it had to support was out of the question. The best Knotts could do was cut her workweek from five days to four, taking herself out of the running for promotions she had coveted but still not getting the round-the-clock time she wants with her kids.

As procreative strategies go, this seems an odd one. If you want to devote yourself exclusively to parenting, it's better to take your reproductive chips off the table after having one child so you can maximize the resources you have to do the job. If you want a multichild family, you'd better make sure that the family bank account is full to bursting.

When it comes to reproduction, though, nothing is quite so easy. Nature abhors deficits and surpluses, and successful parenting often involves spacing births far enough apart so no offspring go hungry but not so far apart that resources go unused. Many mammals nurse a pup or cub or child far longer than necessary because lactation shuts down ovulation and a new pregnancy can be put off until circumstances are right for it. Only when they are will the mother conceive again. "All mother mammals are forced to make the most of the resources available while making trade-offs compatible with their own survival," says Hrdy.

But what happens when this resource-management system breaks down? What if the mother gambles wrong and an offspring comes along when there are no resources to support it, or what if she is too young to care for it? What if the infant is sickly and seems likely to languish no matter how well it's looked after? Humans agonize over these situations, but mothers throughout the animal kingdom show a surprising willingness to abandon or even kill such luckless young rather than pour energy down a bottomless reproductive well.

An American black bear, which normally gives birth to two or three cubs at a time, may walk away from one born alone, calculating that it's better to wait for a multiple birth next year than exhaust herself with a singleton now. Mice will examine offspring after they're born and eat undersize young, improving the overall fitness of the litter and giving themselves a valuable dose of protein in the process.

Things become truly troubling when human beings facing the same difficult circumstances start making equally brutal choices. Anthropologists report that during a three-year period of social upheaval in Bolivia in the 1930s, nearly every mother in an Ayoreo Indian village committed infanticide at least once. In India and China, selective infanticide of baby girls is still commonly, if quietly, practiced. And while there may be less of a history of such killing in the U.S., periodic cases of high-schoolers secretly giving birth and then murdering their infant are proof that such practices know no cultural boundaries.

If an impulse to commit infanticide is indeed part of our genetic legacy, can it be forgiven? Or does such a crime remain a crime no matter how strong the primal drives behind it? Anthropologists take the long view--at least when the crime is abandonment and not murder. "I think we have to re-examine the harsh penalties we place on young, uneducated women who abandon infants," says anthropologist Helen Fisher of Rutgers University. "They were dancing to primitive, natural rhythms, and they got out of synch."

The problem with such scientific forgiveness is that it may give human beings, with their much celebrated free will, too little credit. Most mothers will love and nurture even an unwanted infant because, well, it seems the right thing to do. Most will stretch their resources to the breaking point in order to have a second child not because that's what their genes drive them to do but because they love having children. Critics of the work of Hrdy and others resist drawing too many parallels between human and animal parents, insisting that the few traits that distinguish us from other species are far more important than the many things we share.

"The argument goes that in the highest primates, 99% of DNA is the same as human DNA," says Lawrence Cunningham, a theologian at the University of Notre Dame. "But what's significant is that 1% difference. It is a kind of moral evolution that takes place within humans."

Surprisingly, many scientists agree. "There's a history in primatology of looking at primate species as if they were models for humans," says evolutionary psychologist Leda Cosmides of the University of California at Santa Barbara. "But that's not really the way to do it, because humans are not baboons or chimps, just as baboons are not chimps or humans."

Just what distinguishes the higher species of primates from the very highest one is not always clear, but one of the most important differences seems to be the delight humans take in challenging their primitive urges--and even flat-out defying them. Hrdy writes that when her children were babies, she often cooed to them nonsensical endearments that were oddly evocative of food. "Sweet potato," "muffin," "cutie-pie," she would call them. "I could eat you up," she'd gush. Why she chose those words to babble, she couldn't say, but after a period of what she calls "Darwinian self-analysis," she realized that she might actually be hearing the echo of some genetic programming buried deep within the carnivorous parts of her brain.

Hrdy, of course, never had any real inclination to consume her children with anything other than affection. In fact, she became consumed by them--by their needs, by their demands, by her own impulse to protect them. In human mothers--indeed, in all animal mothers--there has always been tension between much that is sublimely good and at least a few things that aren't so good. It is humans alone, however, who have the ability to contemplate those choices--and then know which ones to make.

--Reported by Dan Cray/Los Angeles, Unmesh Kher/New York and Maggie Sieger/Chicago

With reporting by Dan Cray/Los Angeles, Unmesh Kher/New York and Maggie Sieger/Chicago