The Myth of Monogamy: Fidelity and Infidelity in Animals and People

THE

MONOGAMY

Fidelity and Infidelity in Animals and People

DAVID P. DARASH, PH.D., AND JUDITH EVE UPTON, M.D.

A W. H. Freeman / Owl Book

Henry Holt and Company New York

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Copyright (c) 2001 by W. H. Freeman and Company All rights reserved.

Distributed in Canada by H. B. Fenn and Company Ltd. Library of Congress Cataloging-in-Publication Data Bar ash, David P.

The myth of monogamy : fidelity and infidelity in animals and people / David P. Barash and Judith Eve Lipton. p. cm.

Includes bibliographical references and index. ISBN 0-8050-7136-9

1. Adultery. 2. Sex customs. 3. Sexual behavior in animals. I. Lipton, Judith Eve. II. Title.

HQ806.B367 2001 2001023209

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First published in hardcover in 2001 by W. H. Freeman and Company

First Owl Books Edition 2002

A W. H. Freeman / Owl Book

Designed by Victoria Tomaselli

Printed in the United States of America

10 987654321

To Ilona and Nellie, for helping to mahe It all worthwhile

Contents

CHAPTER 1
Monogamy for Beginners 1

CHAPTER 2 Undermining the Myth: Males 15

CHAPTER 3 Undermining the Myth: Females

(Choosing Male Genes) 57

CHAPTER 4 Undermining the Myth: Females

(Other Considerations) 87

CHAPTER 5
Why Does Monogamy Occur At All? 113

CHAPTER 6 What Are Human Beings, Naturally? 139

CHAPTER 7 So What? 181

Notes 193

Index 223

VII

Acknowledgments

We have been working together for twenty-five years, and we are grateful to each other for deep friendship and wonderful evenings. We thank our editor John Michel for seeing merit in this project and for helping to improve it as it developed. Project editor Jane O'Neill was also crucial in making this book become a reality. We offer particular gratitude to Nellie Barash, our fifteen-year-old daughter, who assisted in correcting page proofs and slang. Thank you, Nellie, for being our culture maven. We want most of all to thank the many researchers who populate the pages of this text and the endnotes for the diligence and insight that has helped expose the myth of monogamy. And we offer our encouragement to everyone-- critters, scientists, and lay people--who struggle with love and betrayal.

"The world is not to be narrowed till it will go into the understanding . . . but the understanding is to be expanded till it can take in the world."

-- Francis Bacon (1561-1626)'

CHAPTER ONE

Monogamy for Beginners

Anthropologist Margaret Mead once suggested that monogamy is the hardest of all human marital arrangements. It is also one of the rarest. Even long-married, faithful couples are new at monogamy, whether they realize it or not. In attempting to maintain a social and sexual bond consisting exclusively of one man and one woman, aspiring monogamists are going against some of the deepest-seated evolutionary inclinations with which biology has endowed most creatures,
Homo sapiens
included. As we shall see, there is powerful evidence that human beings are not "naturally" monogamous, as well as proof that many animals, once thought to be monogamous, are not. To be sure, human beings
can
be monogamous (and it is another question altogether whether we
should be),
but make no mistake: It is unusual--and difficult.

As G. K. Chesterton once observed about Christianity, the ideal of monogamy hasn't so much been tried and found wanting; rather, it has been found difficult and often left untried. Or at least, not tried for very long.

The fault--if fault there be--lies less in society than in ourselves and our biology. Thus, monogamy has been prescribed for most of us by American society and by Western tradition generally; the rules as officially stated are pretty clear. We are supposed to conduct our romantic and sexual lives one-on-one, within the designated matrimonial playing field. But as in soccer or football, sometimes people go out of bounds. And not uncommonly, there is a penalty assessed if the violation is detected by a referee. For many people, monogamy and morality are synonymous. Marriage is the ultimate

2 THE MYTH OF MONOGAMY

sanction and departures from marital monogamy are the ultimate interpersonal sin. In the acerbic words of George Bernard Shaw, "Morality consists of suspecting other people of not being legally married."

Ironically, however, monogamy itself isn't nearly as uncomfortable as are the consequences of straying from it, even, in many cases, if no one finds out. Religious qualms aside, the anguish of personal transgression can be intense (at least in much of the Western world), and those especially imbued with the myth of monogamy often find themselves beset with guilt, doomed like characters from a Puritan cautionary tale to scrub eternally and without avail at their adultery-stained souls, often believing that their transgression is not only unforgivable, but unnatural. For many others--probably the majority--there is regret and guilt aplenty in simply feeling sexual desire for someone other than one's spouse, even if such feelings are never acted upon. When Jesus famously observed that to lust after another is to commit adultery in one's heart, he echoed and reinforced the myth of monogamy--the often-unspoken assertion that even desire-at-a-distance is not only wrong, but a uniquely human sin.

Whether such inclinations are wrong is a difficult, and perhaps unanswerable, question. But as we shall see, thanks to recent developments in evolutionary biology combined with the latest in technology, there is simply no question whether sexual desire for multiple partners is "natural." It is. Similarly, there is simply no question of monogamy being "natural." It isn't.

Social conservatives like to point out what they see as a growing threat to "family values." But they don't have the slightest idea how great that threat really is or where it comes from. The monogamous family is very definitely under siege, and not by government, not by a declining moral fiber, and certainly not by some vast homosexual agenda ... but by the dictates of biology itself. Infants have their infancy. And adults? Adultery.

If, as Ezra Pound once (somewhat self-servingly) observed, artists are the "antennae of the race," these antennae have long been twitching about extramarital affairs. If literature is any reflection of human concerns, then infidelity has been one of humankind's most compelling, long before biologists had anything to say about it. The first great work of Western literature, Homer's
Iliad,
recounts the consequences of adultery: Helen's face launched a thousand ships and changed the course of history only after it first launched an affair between Helen, a married woman and Greek queen, and Paris, son of King Priam of Troy. Helen proceeded to leave her husband Menelaus, thereby precipitating the Trojan War. And in the
Odyssey,
we learn of Ulysses' return from that war, whereupon he slays a virtual army of suitors, each of whom was trying to seduce his faithful wife, Penelope. (By contrast, incidentally, Ulysses himself had dallied with Circe the sorceress, but he was not considered an adulterer as a result. The double standard is ancient and by definition unfair; yet it, too, is rooted in biology.)

monogamy for beginners 3

It seems that every great literary tradition, at least in the Western world, finds it especially fascinating to explore monogamy's failures: Tolstoy's
Anna Karenina,
Flaubert's
Madame Bovary,
Lawrence's
Lady Chatterley's Lover,
Hawthorne's
The Scarlet Letter,
Henry James's
The Golden Bowl.
More recently, John Updike's marriage novels--not to mention scores of soap operas and movies--describe a succession of suburban, middle-class affairs. The present book, by contrast, is not fiction. And it is not concerned with affairs as such, but rather with the biological underpinnings of affairs, in human beings and other animals as well. More precisely, it is about what the latest research has been revealing about the surprisingly weak biological underpinnings of monogamy.

Our approach will be biological, because whatever else human beings may be, we are biological creatures through and through. We eat, we sleep, we feel emotions, we engage in sex, and although we are unique in some regards, so is every other living thing! Rhinos and cobras are uniquely rhinos and cobras in their evolutionary history, their physiology, their anatomy, their behavior, just as human beings are uniquely human. But are we--can we be--
more unique
than other creatures? Moreover, it should quickly become apparent that despite the oxymoronic "shared uniqueness" of all living things, there is also a genuine commonality of pattern, especially--for our purposes--a shared susceptibility to certain basic behavioral tendencies. It is taken for granted that we can learn about human digestion, respiration, or metabolism by studying these processes in other animals, making due allowance, of course, for certain unavoidable differences among different species. The same applies for much, although assuredly not all, behavior.

In this book, we'll be concerned with a range of living things, in part because each is worth understanding in its own right and also because of the light they can shed on ourselves. Don't misunderstand: There will be no claim that because hairy-nosed wombats show a particular sexual pattern, people do, too. Arguments of this sort are absurdly naive, if only because there is such remarkable variety in the animal world. Among so-called lekking species of birds, for example, males gather at a ceremonial plot of ground, with each male defending a small territory; many different females then mate preferentially with one of these males, typically the one occupying the most central "lek" and whose displays are especially intense. (No pair-bond here.) Then there are the pygmy chimps, also known as bonobos, which engage in what seems to be a nonstop sexual free-for-all. Once again, nothing close to monogamy is found ... and these are our closest animal relatives.

On the other hand, there are cases of lifelong social and sexual partnership that might give pause even to the most committed advocates of

4 the myth of monogamy

intimate, intense, altogether faithful male-female bonding: Not many living things partake, for example, of the extreme monogamy shown by the parasitic flatworm
Diplozoon paradoxum,
a fish parasite whose partners meet as virgin adolescent larvae, whereupon they literally fuse at their midsections and subsequently become sexually mature; they then remain "together" (in every sense of the word) till death parts them--in some cases, years later.

The above examples ranged from birds to mammals to invertebrates. And yet it isn't at all clear which is most "relevant" to human beings. If by relevant we mean which one provides a model or--worse yet--a set of rules or some sort of evolutionary premonition as to our "deeper selves," the answer must be: none. But at the same time, each is relevant in its own way. Not only does every animal species cast its unique light on life's possibilities, but each case also helps illuminate a facet of ourselves.

For most laypersons, there is an understandable bias toward mammals, especially primates. But although the lives of chimpanzees, gorillas, gibbons, and orangutans are fascinating and colorful (especially the highly sexed bonobos, about whom more later), the truth is that when it comes to similarities between their lives and those of human beings, these great apes just aren't that great. Birds--at least, certain species--are far more informative.

This is because we're not looking for direct historical antecedents, but rather for similarities based on similar circumstances. Among nearly all mammals, including most primates, monogamy just isn't in the picture. Nor is male care of the young. By contrast, although birds aren't nearly as monogamous as once thought, they are at least inclined in that direction. (The same can be said about human beings.) Not only that, but social monogamy--as opposed to genetic monogamy--is strongly correlated with parental involvement on the part of fathers as well as mothers, a situation that is common in birds and quite unusual among mammals, except for that most birdlike of primates,
Homo sapiens.

In this book, we won't be especially focused on mammals (except for ourselves). When it comes to dispelling the myth of monogamy, most of the really useful discoveries in recent years have come from research by ornithologists, who, interestingly enough, have directed much of their attention to those species that are "polygynous" (where the typical mating arrangement is one male and many females) or "polyandrous" (one female and many males). Only recently have they turned their attention to monogamy, only to discover that it is more myth than reality.