Monkeytalk: Inside the Worlds and Minds of Primates

By Julia Fischer

“Recommended for nonspecialists intrigued by animal intelligence and fans of Frans de Waal’s Are We Smart Enough To Know How Smart Animals Are?” —Library Journal

Monkey see, monkey do—or does she? Can the behavior of non-human primates really be chalked up to simple mimicry? Emphatically, absolutely: no. And as famed primatologist Julia Fischer reveals, the human bias inherent in this oft-uttered adage is our loss, for it is only through the study of our primate brethren that we may begin to understand ourselves.

An eye-opening blend of storytelling, memoir, and science, Monkeytalk takes us into the field and the world’s primate labs to investigate the intricacies of primate social mores through the lens of communication. After first detailing the social interactions of key species from her fieldwork—from baby-wielding male Barbary macaques, who use infants as social accessories, to aggression among the chacma baboons of southern Africa and male-male tolerance among the Guinea baboons of Senegal—Fischer explores the role of social living in the rise of primate intelligence and communication, ultimately asking what the ways in which other primates communicate can teach us about the evolution of human language.

Funny and fascinating, Fischer’s message is clear: The primate heritage visible in our species is far more striking than the reverse, and it is the monkeys who deserve to be seen. “The social life of macaques and baboons is a magnificent opera,” Fischer writes. “Permit me now to raise the curtain on it.”

A Scientific American recommended book

“A lively, personal, and nuanced perspective on primate behavior.” —Dorothy L. Cheney and Robert M. Seyfarth, coauthors of How Monkeys See the World and Baboon Metaphysics

• Language: English
• Publisher: Open Road Integrated Media
• Release date: Jan 4, 2017
• ISBN: 9780226124384

Book preview

Monkeytalk

Monkeytalk

INSIDE THE WORLDS AND MINDS OF PRIMATES

JULIA FISCHER

Translated by Frederick B. Henry Jr.

THE UNIVERSITY OF CHICAGO PRESS

Chicago and London

The University of Chicago Press, Chicago 60637

The University of Chicago Press, Ltd., London

© 2017 by The University of Chicago

All rights reserved. Published 2016.

Printed in the United States of America

26 25 24 23 22 21 20 19 18 17    1 2 3 4 5

ISBN-13: 978-0-226-12424-7 (cloth)

ISBN-13: 978-0-226-12438-4 (e-book)

DOI: 10.7208/chicago/9780226124384.001.0001

Library of Congress Cataloging-in-Publication Data

Names: Fischer, Julia, 1966– author. | Henry, Frederick B., Jr., translator.

Title: Monkeytalk: inside the worlds and minds of primates / Julia Fischer; translated by Frederick B. Henry Jr.

Other titles: Affengesellschaft. English

Description: Chicago; London: The University of Chicago Press, 2017. | Includes bibliographical references and index. | Originally published in German: Berlin: Suhrkamp Verlag, 2012, under title Affengesellschaft

Identifiers: LCCN 2016032594 | ISBN 9780226124247 (cloth: alk. paper) | ISBN 9780226124384 (e-book)

Subjects: LCSH: Primates—Behavior. | Social behavior in animals. | Cognition in animals. | Learning in animals.

Classification: LCC QL737. P9 F56513 2017 | DDC 599.8—dc23 LC record available at https://lccn.loc.gov/2016032594

Affengesellschaft © Suhrkamp Verlag Berlin 2012

The translation of this work was funded by Geisteswissenschaften International—Translation Funding for Work in the Humanities and Social Sciences from Germany, a joint initiative of the Fritz Thyssen Foundation, the German Federal Foreign Office, the collecting society VG WORT, and the Börsenverein des Deutschen Buchhandels (German Publishers & Booksellers Association).

This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper).

For Kurt—my companion in all matters monkey

Contents

Prologue

PART ONE: SOCIAL BEHAVIOR

Primate Diversity

Barbary Macaques: Model Monkeys

Primate Social Systems

Social Organization

Mating Systems

Social Relationships

Chacma Baboons: Into the Wild

Baboon Camp

Long-Term Studies

Aggression

Guinea Baboons: Uncharted Territories

An Expedition to Senegal

Simenti

First Findings

The Evolution of Baboons

Challenges of the Third Kind

PART TWO: COGNITION

What Do Animals Think?

Trophy Hunters and Killjoys

The Social Brain

Physical Cognition

The Basics

Quantities

Space

Time

Social Intelligence

Do Animals Have Culture?

Forms of Social Learning

Gaze Following

Social Knowledge

Theory of Mind

Intentions

Seeing and Knowing

Belief

Metacognition

The Evolution of Intelligence

PART THREE: COMMUNICATION

What Is Communication?

Senders and Receivers

Information

Signals and Cues

The Function of Monkey Sounds

Communication in Conflicts

Mating Calls

Group Coordination

The Evolution of Language: Beginnings

Early Theories

A Pioneer

Elements of Linguistic Competence

Ape Language Projects

Language Training for Apes

Symbolic Languages

Natural Communication in Primates

Alarm Calls

Vocal Behavior

Dialects

Development of Reactions

Perception of Gradual Differences

Word Learning in a Domestic Dog

The Evolution of Language: State of the Art

Syntactic Abilities

Is There a Gene for Language?

Gestural Communication

Intentional Communication

Just for the Fun of It

The Evolution of Communication

Conclusion and Prospects

Acknowledgments

Notes

References

Index

Prologue

What’s it like, honestly, to study something of no interest to anyone? I was at a party when another guest engaged me and casually asked about my job. I spoke with enthusiasm about the construction of our field station in Senegal and how thrilling it was to work with the baboons there. Yet before I could finish, he broke in with this question. I was shocked. I had never encountered this response. Whenever I settle into my seat for a long flight, I’m cautious about mentioning my work. When people learn that I study monkeys, their initial surprise gives way to a barrage of questions. Do monkeys have language? Are they really that intelligent? Had I ever lived in the jungle, like that famous chimpanzee researcher . . . what’s her name . . . the one who was killed by poachers? Jane Goodall? I rush to explain that Jane Goodall is very much alive, and that they are thinking of Dian Fossey, the gorilla researcher who was found murdered in her beloved Virunga Mountains. Next I tell them more about the animals, how they live and communicate, and I make sure to emphasize that while we know quite a lot today, there is much that remains to be understood.

Primates are fascinating creatures, remarkably similar to us and yet at the same time very different. This fact was apparent even to a little boy watching monkeys in a zoo. Gazing wide-eyed at a monkey, he shouted: Look! He’s got hands on his feet! Strictly speaking I should say that other primates fascinate us, because humans also belong to the Primate order. Primate research promises insights not only into our evolutionary origins; it serves as a foil for characterizing our own species. What differentiates us from our nearest primate relatives? What traits belong specifically to other primates and which ones exclusively to humans?

Yet nonhuman primates (hereafter primates)¹f deserve our attention not just as a lens for bringing into sharper focus our own species. The diversity of their appearances and ways of living, the spectrum of their behaviors, the complexity of their social lives—these are all worthy of interest in their own right. Primates are fascinating species for many other reasons than a simple family resemblance to our own.

This book is intended for anyone who, like my curious travel companions or the little boy at the zoo, is fascinated by primates and their social lives. And because so many ask what life in the company of monkeys is truly like, I’ll share some of the attractions, challenges, and peculiar experiences of doing fieldwork in far-off places.

My research focuses on the relationship between the social system, intelligence, and communication of primates. A basic assumption is that intelligence arises in response to the challenges of living in complex social groups. This point needs to be carefully explored, along with the idea that intelligence and communicative capabilities are intimately interconnected.

The book is divided into three parts. First, I share some insights into the social lives of monkeys with an emphasis on the three African species I have studied. The second part is devoted to the question of primate intelligence. How smart are primates? Do they learn from others? How much do their cognitive abilities and knowledge differ from those of other animals? And what special demands does life in the wild put on them? Here I introduce two differing research paradigms: on the one hand, tests carried out on captive animals in the tradition of experimental and developmental psychology; on the other, field investigations that aim to shed light on problem-solving strategies of free-ranging animals. The third and final part of the book addresses communication. I pose the question of what the study of primate communication can tell us about the evolution of human language. At the end, I’ll attempt to tie it all together.

One of the main goals of my scientific work is to shed light on the evolution of human social behavior, intelligence, and language. I argue that human intelligence and communication are in many ways distinct from that of primates, and that commonalities exist more so in the social domain, in the special significance of social bonds. I find that the primate heritage in humans is more remarkable than what is somewhat human in other primates. But whether one emphasizes similarities or differences between our kindred species is a matter of personal inclination or intellectual style.

I wasn’t destined to become a primate researcher. Some people know even in childhood that when they grow up they want to sort through fragments of ancient pottery or work in theater set design. But so many things held my interest: languages, the social sciences, biology. I realized only much later that primatology brought together all my various interests. In addition, because I had spent many of my youthful years as a dedicated homebody, I was surprised to find that I loved life in the wilderness. The allure of primate research lies in the diversity of its intellectual and practical challenges. My regular reading includes monographs on behavioral biology as well as philosophical essays and the wilderness survival handbook, Where There Is No Doctor.²f I’ve learned how to use the sun as a compass and to repair water supply lines destroyed by elephants. Out in the field, seven lionesses made themselves at home near our dinner table. I’ve had to learn great patience and I’ve suffered many setbacks. Nevertheless, at the end of the day, this work is profoundly rewarding. The social life of macaques and baboons is a magnificent opera. Let me now raise the curtain on it.

PART ONE

Social Behavior

PRIMATE DIVERSITY

The stars of our show are Barbary macaques, chacma baboons, and Guinea baboons. Before I provide a more detailed description of these species, a few notes on the varied appearances and habits of primates in general are called for. The Primate order is marked by an extraordinary diversity of physical form, lifestyle, and social organization. The spectrum runs from the solitary aye-aye, a nocturnal lemur of Madagascar that taps for insects under tree bark with its long and slender middle finger, to South American squirrel monkeys living in large colonies, to harems of gorillas, whose adult males can reach a size of four hundred pounds.

Primates originated roughly eighty million years ago.¹ The nearest living relatives of ancestral primates are the Philippine flying lemur and the Southeast Asian tree shrew, both of which give a sense of what life might have been like for the earliest primate species. Today the Primate order comprises two main lines. First, there are the Strepsirhini, including the galagos (bush babies), pottos, lorises, and Madagascar lemurs. A well-known example is the ring-tailed lemur with its distinctive black-and-white ringed tail. The second group is the Haplorhini, which includes tarsiers, small nocturnal primates of Southeast Asian rain forests, and true simians. The true simians appeared fifty to thirty-six million years ago and comprise New World and Old World monkeys. The latter group includes tailed Old World monkeys, small apes such as gibbons, and the great apes—that is, orangutans, gorillas, chimpanzees, bonobos, and humans.

Among tailed Old World monkeys are the baboons, which I describe in greater detail below, and macaques such as the rhesus monkey, Barbary macaque, and Japanese macaque. Japanese macaques are especially famous for, and frequently photographed enjoying, their snow-encrusted hot spring baths. The guenons belong to this taxonomic group as well. One species in this group, the vervet monkey, has played a particularly important role in research on the communication of primates, and I will return to them in the third part of the book. In addition, the tailed Old World monkeys include colobine monkeys, prominent examples of which are the Asian Hanuman langurs and the black-and-white colobus monkeys of Africa with their showy and magnificent coats.

Figure 1. Family tree of the primates (credit: Laura Almeling).

BARBARY MACAQUES: MODEL MONKEYS

I have studied Barbary macaques for many years, but I hadn’t originally planned to do so. I had intended to become a marine biologist. After finishing my studies at the Free University of Berlin and the University of Glasgow, I was ready to begin doctoral work at the Sea Mammal Research Unit of Cambridge University. My final requirement was a course in behavioral biology. This took me to Rocamadour in southwestern France to investigate the social behavior of Barbary macaques at Le Forêt des Singes. Kurt Hammerschmidt, Henrike Hultsch, and Dietmar Todt, who later became my doctoral advisor, directed this fieldwork. The monkeys here, cavorting energetically around the park, gave me far greater inspiration than seals sprawling and loafing on a sea coast. Kurt is my best friend, and we continue to collaborate today as we did back then to shed light on the evolution of communication.

Figure 2. Family tree of Old World primates (credit: Laura Almeling).

La Forêt des Singes—like the Trentham Monkey Forest in Staffordshire, England, or Monkey Mountain near Lake Constance in Germany—is mainly a tourist attraction. Visitors can stroll along established paths in the reserve and view the monkeys up close. But these parks are also well suited for scientific research and education. At Rocamadour, roughly 150 animals roam freely in three groups over an area of twenty hectares. They are given food and receive annual medical examinations,² and live under no threat from predators—it is truly a monkey paradise. As Kurt observed: The monkeys would happily visit their native wilderness, but they would be on the airplane the instant it headed back home. Hormonal contraception keeps the monkeys’ birth rate in check. Despite these benefits for the monkeys, studies of captive animals are limited in the sort of questions they can reasonably pose. For example: Which male has the greatest mating success? Or: How much time must the animals spend in their daily quest for food? These are questions for which animals in captivity can provide no meaningful answers. On the other hand, because they are accustomed to humans and readily participate in non-intrusive experiments, such captive animals are ideal for studies of communication and intelligence.

Barbary macaques are the only macaques found in Africa, specifically in the forests and mountains of the middle and high Atlas, the mountainous Rif region of Morocco, and Kabylia in Algeria. There is a small population in Gibraltar as well. All other macaques are indigenous to Asia. Through evolution in harsh climates, the Barbary macaque has lost its tail, and for some time this led them to be classified with apes. In fact, the tail hasn’t completely disappeared, as a small stub still remains. Over the cold winter months, they insulate themselves with a thick coat of fur. Autumn is mating season, and after a six-month gestation period, newborns arrive in the spring. Births usually happen in the evening or at night, when the danger of predators is minimal. In contrast to the brownish-yellow color of the adults, newborns have a pitch-black coat and pink faces and hands.³ A distinctive newborn coat is a common feature of many monkey species. Baboon infants are also black, except for those of the little-studied Kinda baboon, which are born with white fur.

The baby monkey spends the first week of its life clinging to its mother’s belly.⁴ It grasps its mother’s fur tightly with its hands and feet. If it lacks strength to hang on, the mother supports the baby with her free hand. After a few weeks, the baby is shifted to its mother’s back. Among the tailless Barbary macaques, infants take a jockey position on the shoulders of the adult. Baboon babies, once a little bit older, can sit comfortably upright on the mother’s back, leaning against her raised tail. But in Barbary macaques, mothers are not the only ones who care for and transport the young. More than in any other macaque species, male Barbary macaques express great interest in the little ones. Males frequently take the baby from its mother soon after birth and tote it around. Scientists initially believed this was an expression of paternal affection and concern for offspring, but genetic investigations disproved this idea. A second interpretation was that males sought popularity with mothers so as to have greater reproductive success in the next breeding season, but this argument was likewise found unsustainable. A third possibility remained, that infants were a kind of status symbol for males,⁵ and, indeed, newborns do in fact play a major role in male social relationships. If a male is carrying an infant, he can more confidently approach another male and engage in mutual grooming than if he approaches alone. When two male Barbary macaques sit together holding an infant, they often engage in a peculiar ritual, lifting the baby up high, nuzzling it, and thoroughly inspecting it. They chatter their teeth, smack their lips, and emit deep grunting sounds. Sometimes they will bask in the afterglow, calmly remaining beside each other, while at other times one of the males will brusquely snatch the infant up and rush off to repeat the ritual with another male. The more time a male spends with an infant, the greater his chances for such triadic interactions. Yet this attention, this curious babysitting, is an expensive investment. As we discovered, the longer and more often males took responsibility for infants, the higher the levels of their stress hormones.⁶ Still, males who make a greater investment in infant care are rewarded with a prime position in the male social network, and those who build strong social bonds with male partners in the spring received continuing future support from these partners.⁷ Furthermore, evidence is growing that males with many strong social bonds have a greater reproductive success and thus transmit more genes into the next round of evolution.⁸

Success in evolution is defined as the number of gene copies transmitted to the next generation. As a consequence, an organism is not restricted to investing in the production of its own offspring, but may also aid in the reproduction and survival of its kin. The more closely individuals are related—in other words, the more genetic material they share—the more valuable it is to support each other’s offspring. The totality of all transmitted gene copies is what is called inclusive fitness.⁹ Interestingly, even in the field of biology, a number of scientists were initially hard-pressed to accept this insight and the revolutionary ideas stemming from it, which gave impetus to the new field of sociobiology. The problem many had with this new field was that its key principles seemed to suggest social Darwinism, a brutal survival of the fittest. What might make for success, though, is not always readily predictable. In dynamic and uncertain conditions, there may be advantages to being small, agile, and defensive. With the refinement of sociobiological theory and the death of several of its most influential protagonists and fiercest critics, such as Stephen Jay Gould, the heated ideological debate over sociobiology has for the most part subsided and become a subject for the history of science.¹⁰ And even those who accept the insights of sociobiology may freely choose not to follow its dictates. My genes can jump into the lake, the evolutionary psychologist Steven Pinker once remarked about his childlessness.¹¹

Figure 3. Barbary macaques in Rocamadour (photo: Laura Almeling).

Like many primates, Barbary macaques are captivated by newborns. When I first observed a big group of monkeys fascinated by an infant, it occurred to me that a group of people cooing over a baby stroller was equally exhibiting primordial primate behavior. The enormous interest that group members take in a newborn isn’t entirely without risk, however. A baby might be safely paraded around the neighborhood by a male, but it might just as easily be kidnapped by a senior or higher-ranking female and never returned to its mother.

Older, more experienced female Barbary macaques give birth early in the breeding season. These females know how to get their babies back from the males. Younger females have a more difficult time with this. At the birth of their first baby, they often have no idea how to cope. I once observed a young mother—in human terms a case of teenage pregnancy—carrying her infant around clumsily. She even sat down on top of it. Eventually she mastered how to properly carry her baby but at times still left it unattended. When the baby began to scream, she would hurry over and play with it. Fortunately, the infant was robust, and after several days the mother had gotten the hang of things. Such cases clearly show how learned experience is crucial for infant care. As I explain later, monkeys have an exceptional capacity for learning in numerous situations. But more importantly, the monkeys are not only capable of learning—they need to learn.

Young Barbary macaques fortunate enough to survive the risky newborn phase with a competent mother spend the first months of their lives either with her or in the care of a male. Males commonly develop an interest in a particular infant. The infant thus has a primary male caregiver and perhaps one or two auxiliary ones. The primary male brings the infant to its mother when it is thirsty or hungry. However, sometimes a male will sit for long periods holding an infant tightly by its ankle, totally unswayed by its cries (see fig. 5).¹²

Figure 4. Male Barbary macaque with infant (photo: Kurt Hammerschmidt).

Figure 5. A male Barbary macaque holds on tightly to an infant’s foot (photo: Julia Fischer).

Over the summer, the baby’s fur gradually takes on adult coloration. A golden streak graces the eyebrows. The pink face first pales and then bit by bit takes on adult coloring. The hands and feet grow darker and become almost as black as the tiny fingernails and toenails. The motor skills of the young monkeys rapidly improve. We sometimes describe three- to four-week-old monkeys as frogs because of how awkwardly they hop about, but within a few months they develop a normal gait. During this period, the most significant social partners besides the mother are other juveniles. The whole world is a playground: it is climbed on, balanced upon, and actively explored.

Figure 6. A Barbary macaque’s hands and feet (photo: Naema-E. Schlagowski).

As in humans, mothering assumes different styles, varying with individual experience, personality, and sex of the infant. Some monkey mothers are overly protective, never letting their young ones have the freedom to explore the world as they want. Others, by contrast, are relaxed and let the infant choose whether to keep close to home or venture farther afield to play with others. In the first year of life, mother and child undergo a role reversal. Early on, the mother follows her infant solicitously, but as she prepares herself for another pregnancy by weaning, the infant suddenly finds itself chasing after its mother. It can no longer freely approach to nurse. Barbary macaque mothers wean their daughters earlier than their sons. This has been linked to the fact that males have little contact with their mothers after weaning, so a mother may keep a son around for a while longer, whereas daughters remain the most significant social partners of their mothers throughout life.¹³ During the weaning period, dramatic scenes may take place. I have seen a mother shielding her breast with her arm to prevent an infant from nursing, while the infant, throwing a tantrum, protested loudly with bristling fur and flashing teeth. Some young seem even to blackmail their mothers: they throw themselves from trees, somersault, and roll in the dirt. At first the mother may relent and permit the infant to nurse again. I once watched a mother offer her breast to an infant after a long tantrum, and then quickly withdraw it—apparently the infant had bitten her. In retaliation, the mother gave the baby a powerful bite on the leg. Among monkeys there is definitely a form of strict discipline.

The eminent evolutionary biologist Robert Trivers published a seminal work on this topic in the 1970s, in which he elucidates the parent-offspring conflict.¹⁴ He argues that it is initially in the interest of the parent, in this case the mother, to invest maximally in its offspring to ensure their survival. In this first phase, the interest of the offspring is aligned with that of its parent. This state breaks down the moment the mother becomes ready for new offspring. She must gradually withdraw her investment, so to speak, in her existing offspring and reallocate the assets into a fund for future offspring. Hence, for example, she stops nursing and sets in motion the physical preparations for a new pregnancy. A similar logic underlies so-called sibling rivalry. On the one hand, an infant naturally seeks for itself the lion’s share of maternal care and affection; on the other, by evolutionary imperative, the number of