UP ON THE MOUNTAINS the midday sun glared fiercely, but down in the valley near the swift-running stream it was cool and still. I stood listening until I heard a faint rustling of leaves—the only sound to betray the presence of the group of chimpanzees I was trying to approach.
Slowly and quietly, but making no attempt to hide, I moved toward the great apes until I was only thirty feet away. As I sat down, they watched me, staring rather hard, and a young female who had been lying on the ground climbed a little way up a tall fig tree.
One of the males stood upright to watch more closely. He was a superb specimen, standing about 4 1/2 feet in height, his massive shoulders and bull neck suggesting the tremendous strength in his arms. He must have weighed a good 130 pounds, and he was strong enough to snap with one hand a branch so tough that a man would be hard put to break it with two.
Later I was to learn how it feels to be slammed on the head from behind by a large male chimpanzee, but fortunately for me he did not continue his attack.
After a moment or two, the group stopped looking my way, recognizing me for the strange hairless primate they had grown accustomed to seeing amid the other mountain fauna. The six adults rested on the ground or stretched out along the branches of a wild fig. Nearby, four youngsters played quietly.
I thought then, as I always think when I am face to face with mature chimpanzees in their native forests, of the striking difference between the wild apes and those in captivity. The chimpanzee imprisoned behind bars is bad tempered in maturity, morose, moody, and frequently rather obscene; in his freedom he is majestic even when excited and, for the most part, dignified and good natured.
For about an hour I sat with the group. Then one of the males stood up, scratched thoughtfully, and moved off down the valley. One by one the others followed, the infants riding astride their mothers' backs like diminutive jockeys. The females and youngsters stared at me as they passed. The males scarcely glanced in my direction. Africa Fulfills a Life's Ambition
To be accepted thus by a group of wild chimpanzees is the result of months of patience. In England, before I commenced my field study, I met one or two people who had seen chimpanzees in the wild.
"You'll never get close to chimps—not unless you're very well hidden," they told me. At first it seemed they were right, but gradually I was able to move nearer the chimpanzees, until at last I sat among them, enjoying a degree of acceptance that I had hardly dreamed possible.
At this intimate range, I observed details of their lives never recorded before. I saw chimpanzees in the wild hunt and kill for meat. Though this had been suspected, nobody dreamed that a chimpanzee would attack an animal as large as a young bushbuck, until I saw an ape with his kill.
Most astonishing of all, I saw chimpanzees fashion and use crude implements-the beginnings of tool use. This discovery could prove helpful to those studying man's rise to dominance over other primates. Chimps Threatened by Civilization
I cannot remember a time when I did not want to go to Africa to study animals. Therefore, after leaving school, I saved up the fare and went to Nairobi, Kenya. There I was fortunate in meeting and working for Dr. Louis S. B. Leakey, then Curator of the Coryndon Museum. After a year, Dr. Leakey asked me if I would undertake a field study of chimpanzees.
Although the chimpanzee has been known to science for nearly three centuries, and although, because of its striking resemblance to man, it has been used extensively as an experimental animal in medical and other fields, no attempts had been made to study this ape in its natural habitat until Dr. Henry W. Nissen made his pioneer study in French Guinea. I found his 1931 report invaluable as I prepared my own program.
The primary aim of my field study was to discover as much as possible about the way of life of the chimpanzee before it is too late-before encroachments of civilization crowd out, forever, all nonhuman competitors. Second, there is the hope that results of this research may help man in his search toward understanding himself. Laboratory tests have revealed a surprising amount of "insight" in the chimpanzee-the rudiments of reasoned thinking. Knowledge of social traditions and culture of such an animal, studied under natural conditions, could throw new light on the growth and spread of early human cultures.
Nineteen months after Dr. Leakey suggested the field study, I had received funds for a preliminary investigation from the Wilkie Foundation, Des Plaines, Illinois, which supports studies of man and other primates. I was ready to set out for a three-month visit to the Lake Tanganyika region. The authorities were unwilling to allow a single European girl to go off into the bush by herself, and so my mother accompanied me. Bumps and Dust for 840 Miles
From Nairobi it took us more than five days to reach the Gombe Stream Game Reserve in Tanganyika, a 60-square-mile protected area set aside by the British where I would do my research. The Land-Rover was heavily overloaded, and most of the 840 miles of earth roads were in terrible condition.
Eventually, after innumerable delays, we reached Kigoma, a small European settlement overlooking Lake Tanganyika. There I hired the government launch to take us on the last stage of the journey-the 16 miles up the lake to the Gombe chimpanzee reserve.
Game Ranger David Anstey had arranged one of his semi-annual visits to the reserve to coincide with our arrival. As we traveled up the crystal-clear lake, I studied the terrain where I was to work. The mountains rise steeply from the narrow beach and are broken by innumerable valleys and gorges. The valleys are thickly forested, but the upper slopes become open woodland and many of the peaks and ridges are treeless. Most of the wild chimpanzees in Africa inhabit the dense rain forests of the Congo and west coast. The more open country of the Gombe Stream Reserve is ideal for field study, though the behavior of apes living there might not be the same as that of apes in the dense forests.
Our talk as we sailed the lake was about chimpanzees, and one of Ranger Anstey's stories persuaded me that they can be dangerous when cornered.
He told me of an African who decided to climb an oil-palm tree to cut down some nuts for cooking oil. A chimpanzee was high in the tree, feeding on the nuts, but the African failed to notice the animal until he had climbed well up the trunk. The ape, intent on feeding, only then saw the African, started rapidly down, and as he passed the man, hit out at him, slashing away half his cheek and one eye as he did so.
At about 2 o'clock on the afternoon of July 14, 1960, we arrived at Kasekela, a campsite midway along the 10-mile coastline of the reserve. The motor launch went back to Kigoma, with orders to return for David a few days later. We found ourselves on the beach, surrounded by untidy-looking crates and bundles, together with the small boat and its outboard motor which would be our only link with civilization. Our permanent party numbered four: myself; my mother; Dominic, our African cook; and Dominic's wife.Despair Marks First Field Studies
As we set up camp that first day, we found the heat almost intolerable, but the big tent was soon pitched and everything bundled inside. I shall always remember David's expression when he found that our only tableware consisted of a couple of tin plates, a cup without a handle, and a thermos top! Indeed, pwe were equipped with only the barest essentials, and I think even Dominic was secretly shocked.
During the first two months of my field studies, I often despaired. Each dawn I set out alone, following the little streams as I explored the valleys one by one, forcing my way through the dense undergrowth or scrambling up the steep slopes. Sometimes I saw a group of chimpanzees feeding in a tree, but seldom managed to get close before the shy apes moved away. Frequently I heard their noisy calling, but usually they had moved off before I could catch up with them. Disheartened, I trudged wearily back to camp each dusk.
But those early days, however frustrating, initiated me into the ways of mountain life. The forests no longer seemed hostile after I learned to creep along pig trails instead of forcing my way through the undergrowth. The slopes were no longer a nightmare when I had discovered the baboon trails where I could pull myself up the steepest parts by roots worn smooth by constant use. I became acquainted with other animals: troops of vervet and redtail monkeys; the beautiful red colobus monkey; the shy bushbuck; the fat ginger bush pig.
One morning, while walking along the lake shore, I was approached by an excited fisherman who showed me a tree into which a bull buffalo had chased him the night before. "Huyu kali sana," the man said. "He's a bad one, this fellow."
Indeed, the tree was scored by innumerable gashes from the buffalo's horns. Mostly, however, the small herds are wary and hard to approach.
Once I did have to climb a tree, when I met two crotchety old bulls along a narrow track. My climb to safety was speeded by memory of Dr. Leakey's opinion of them.
"I'd rather meet a rhinoceros or a lion any day. I am more frightened of the buffalo than of any other creature in Africa."
Often I saw the tracks of a leopard, or recognized its powerful feline smell, and sometimes I heard the soft rasping of its hunting call. Many months later I saw one. He passed only a few yards away in the long grass, and I felt slightly apprehensive. But when he winded me he turned silently away.
One-girl Camp Set Up Near Chimps
I never attempted to hide, and gradually the animals became used to the strange paleskinned primate that had invaded their territory. After about six months, most of the chimpanzees would sit and look at me calmly at distances of 100 yards. At first they fled if they saw me within 500 yards.
Three-quarters of an hour's climb from camp, I discovered a peak overlooking two valleys and many open grassy ridges and slopes-an ideal place for long-distance observation. From the peak I could locate a group and then try to get closer. I had a tin trunk carried up there, with blanket, electric torch, a couple of tins of baked beans, coffee, and a kettle. When the chimps slept close by, I stayed up in the mountains near them.
So, gradually, I began to learn the basic behavior patterns of the chimpanzees, and after six months I was able to pick out and name some individuals. When I saw Mike lazing in the sun, for example, or Count Dracula ambling past, it was like meeting a friend.
People often ask me how I choose such names for individual chimpanzees. My answer is that some names—such as Mrs. Maggs, Spray, and Mr. McGregor—simply come to mind. Strange as it may sound, some chimpanzees remind me of friends or acquaintances in some gesture or manner and are named accordingly.
One chimpanzee had a pale, flesh-colored face instead of the dark color common in adults. It gave me a slightly eerie feeling when I first saw him close to, and ever after that he was "Count Dracula." Study Extended by Society Grant
When the three preliminary months came to an end, the National Geographic Society took over sponsorship of my research and financed a further 20 months. My mother had to return to England, but by then I was accepted by the authorities and so was allowed to stay on at the reserve.
At this time I was joined by Hassan, of the Kakamega tribe, an African who had worked for Dr. Leakey for 15 years-a most responsible and reliable helper. He took over the little boat and the monthly trip to Kigoma for stores and mail. The trial period was over, and I could settle down to building a closer contact with the apes.
Chimpanzees are nomadic within their territory, and they follow no fixed circuit. They have no regular sleeping trees. Most chimpanzees in the reserve-probably between 60 and 80 individuals-range, at various times of year, over the whole 60 square miles, and sometimes beyond the boundaries. The distance and direction of their wanderings-they may travel as much as eight or ten miles in a day-depend on the seasonal availability of the fruits, leaves, and blossoms that form the bulk of their diet.
The chimpanzees during much of the year move about in small groups of three to six animals. Such a group, I discovered from observation, may consist of adult males and females, of females and juveniles, of males only, or of a mixture of sexes and ages.
During the day two or three small groups may join and move about together for a few hours or a few days. In certain seasons, mainly when some kind of favorite fruit is plentiful, I have often seen as many as 25 chimpanzees together.
What makes the social pattern so complicated is that the small groups are not stable. When two groups which have joined temporarily separate again, there has frequently been an exchange of individuals. Males often leave the group they are with to move about alone, subsequently joining another group or another lone male.
This casual, free-and-easy grouping makes it harder to recognize individuals, yet it is essential to do so before one can even begin to understand the social pattern.
From my mountaintop perch, I observed how chimpanzees go to bed. Every night each one makes its own sleeping platform, or nest—except for the small infants, which sleep with their mothers until they are about three years old.
Treetops Provide Springy Mattresses
The construction of a nest, I found, is simple and takes only a couple of minutes. After choosing a suitable foundation, such as a horizontal fork with several branches growing out, the chimpanzee stands on this and bends down a number of branches from each side so that the leafy ends rest across the foundation. He holds them in place with his feet.
Finally he bends in all the little leafy twigs that project around the nest, and the bed is ready. But the chimpanzee likes his comfort, and often, after lying down for a moment, he sits up and reaches out for a handful of leafy twigs which he pops under his head or some other part of his body. Then he settles down again with obvious satisfaction.
One evening I sat quietly below a group of five chimpanzees that were feeding in a tree. There was Mrs. Maggs with her two offspring: little Jo, about two years old; and Spray, then about five. There was another mature female, Matilda, and a young male, Hugh.
Just before sunset there was excited calling as another male joined the group. Spray climbed down from the tree and ran up the slope to greet him. As they climbed the tree together, I saw that the newcomer was Mr. McGregor, an old male who had lost the hair from his shoulders and was almost completely bald-headed-a rarity in chimpanzees.
The group fed quietly until the sun had almost vanished behind the mountains across the lake, and then Mrs. Maggs began looking for a place to make her nest. She tested the branches exactly the way a person tests the springs of a hotel bed. One by one, the other apes began to make their nests.
Drowsy Mother Cuddles Little One
When the sun finally sank out of sight, Mrs. Maggs was lying on her back in her completed nest. As the chill of night crept into the air, little Jo ran to her mother, who put out her arm and drew the young one close to the warmth of her body.
Darkness fell swiftly and I climbed to my mountaintop lookout post, opened a tin of beans, and boiled my kettle over a little fire. The moon was nearly full, and the mountains were beautiful and rather ghostly when I returned to the chimpanzees. I disturbed them as I settled down with my blanket about 50 yards away, and they began to call out loudly, alerting a troop of baboons sleeping in the valley below. The chimpanzees soon quieted down, but the baboons went on barking for a long time.
The chimpanzees slept soundly for the rest of the night, but I was perched halfway down a steep slope with only a small tree to keep me from slithering into the ravine below. I was glad for the first glimmering of dawn.
As it grew lighter I gradually made out the dark shape of Mrs. Maggs, with Jo curled up beside her. Soon Jo sat up, yawned, and gazed about. Mrs. Maggs rolled over onto her back, flung out an arm, and also yawned. Jo jumped onto her chest, leaned forward, and pressed her face against her mother's, flinging her arms around her neck. Chimps Awake in Mood for Fun
The other apes began to move. I could see Matilda sitting up in her nest and Spray feeding in a tree close by.
Jo became restless. She climbed to a branch above the nest and hung down, kicking and twisting from side to side. Her mother reached up and patted her, pushing her to and fro, until Jo, delighted, tumbled down on top of her. Mrs. Maggs, her legs in the air, bounced Jo up and down with her feet and then suddenly bent her knees so that Jo collapsed in a heap of waving arms and legs.
The game went on for about ten minutes; then Mrs. Maggs suddenly sat up and peered down through the branches. Matilda had left her nest, and sounds below indicated that the others were moving away. Mrs. Maggs touched Jo, who jumped to her at once, clinging under her belly as the mother swung down from the tree.
When a chimpanzee is born, it is almost as helpless as a human baby, save that it rapidly develops great strength in hands and feet, enabling it to cling to its mother's long hair as she travels from place to place.
For the first four months the infant never leaves its mother, but after this it begins to venture first a few feet and then a few yards away. It is still very unsure of itself, and the mother is always ready to reach out should it lose its balance.Babies Play Like Human Children
By the time the infant is about a year old, it has more confidence and spends hours playing gently, hanging from a branch and patting at its toes, or doing careful gymnastics on a branch. If two infants play together, they pat out at each other or have a tug-of-war with a twig. Always the games are slow and gentle.
By the time they are about two years old, the little apes are very active and their playing far more adventurous. Whether they are swinging and leaping around in a tree or rolling over and over on the ground, they never seem to be still for a minute.
Their elders, particularly the adolescents and the younger males, are amazingly goodnatured with them. I once watched little Fifi tormenting an adolescent male, Figan. He was resting peacefully when Fifi hurled herself onto him, pulling his hair, pushing her fingers into his face, biting his ears. She swung above him, kicking out, while he indulgently pushed her to and fro with one hand. Finally, exhausted for the moment, she flung herself down beside him.
From the age of about three years the young chimpanzee becomes more and more independent. Often it still moves around with its mother until it is five or six, but it no longer rides on her back or sleeps in the nest with her at night. Games become rougher and wilder, wrestling and chasing being the favorite sports.
Occasionally a small infant tries to join in, and then the older ones treat it with great consideration. I saw one youngster swinging an infant gently by one arm and then, after peering down, she dropped the little one to a leafy platform a few feet below. When the infant had difficulty in climbing up again, she gave a helping hand.
At about eight years, the chimpanzee child attains puberty, and during the next three or four years of adolescence it gradually takes its place in adult society. How long it might live, no one can say pending further study, but a good guess for average life span in the wild would be 40 to 50 years. Chimps Express Feelings in Action
In this society, relationships among the adult apes are more harmonious than had been assumed from observations of chimpanzees in captivity. Of course, if you judged from sound alone, you would imagine that wild chimpanzees were always fighting and quarreling. When two groups meet there is sometimes a fantastic cacophony as the males call loudly, drum on tree trunks, and shake branches, while the females and youngsters scream and rush out of the way. But this is merely excitement and pleasure; with his highly emotional extrovert temperament, the chimpanzee likes to express his feelings in action.
When squabbles do arise, often over the merest triviality, they are usually settled by gestures and loud protest. Once I was watching a youngster feeding peacefully beside an adult male. By chance, they both reached for the same fruit. The youngster immediately withdrew its hand, but screamed loudly and "flapped out" at the male. The male screamed and flapped at the youngster. This went on for a few moments and then the quarrel ended, neither ape having touched the other.
Relationships between mature and adolescent males are particularly harmonious-they do not even fight over females! I once saw seven males in succession mate with a single female, with no sign of jealousyor antagonism.
As to mating in general, chimpanzees in captivity breed all year round, and it seems likely that this is the case in the wild, because females appear receptive toward males during all months of the year. In addition, I saw small infants in April, June, September, and October.
During September and October, however, when the chimpanzees are frequently seen moving about in large aggregations, excitement, caused by this social stimulation, does appear to have a very marked effect upon reproductive behavior. I saw the animals mating almost daily during these two monthsspring in Tanganyika. Thus, although it would appear that a certain amount of mating must take place throughout the year, there is, apparently, a very definite mating season.
Mutual grooming plays an important part in the social life of chimpanzees, and two friends, or even a small group, will sit quietly for hours searching through each other's long black hair for specks of dirt, grass seeds, or ticks.
Some students of animal behavior see in this grooming activity the first beginnings of true social and altruistic behavior in the whole animal kingdom. Calls and Gestures Serve as Language
I am often asked, "Do chimpanzees have a language?" They do not, of course, have a language that can be compared with our own, but they do have a tremendous variety of calls, each one induced by a different emotion.
The calls range from the rather low-pitched "hoo" of greeting, and the series of low grunts that is heard when a chimpanzee begins to feed on some desirable food, to the loud, excited calls and screams which occur when two groups meet.
One call, given in defiance of a possible predator, or when a chimpanzee, for some reason, is angry at the approach of another, can be described as a loud "wraaaah." This is a single syllable, several times repeated, and is one of the most savage and spine-chilling sounds of the African forest.
Another characteristic call is a series of hoots, the breath drawn in audibly after each hoot, and ending with three or four roars. This is the cry of a male chimpanzee as he crosses a ridge. It seems to be an announcement to any other chimpanzees that may be in the valley below: "Here I come."
These calls, while they are not a language in our sense of the word, are understood by other chimpanzees and certainly form a means of communication.
In addition, chimpanzees communicate by touch or gesture. A mother touches her young one when she is about to move away, or taps on the trunk when she wants it to come down from a tree. When a chimpanzee is anxious for a share of some delicacy, he begs, holding out his hand palm up, exactly as we do. He may pat the branch beside him if he wants a companion to join him there. When two animals are grooming each other and one feels that it is his turn to be groomed, he often reaches out and gives his companion a poke.
Once, when three males were all grooming one another, I saw a female going round poking at each of them in turn. But she was completely ignored-and so sat down sadly and groomed herself! There are also many gestures of greeting and friendship. Sometimes when two friends meet after a separation, they fling their arms around each other in a delighted embrace.
Despite this fairly well-developed system of communication, a chimpanzee suddenly confronted with danger gives no alarm call to warn his companions, but simply runs off silently.
Defiant Glares Greet Visitor
This was the way the apes initially reacted to my presence, but after a few months fear gave place to curiosity. Curiosity, in turn, changed to defiance. Then, instead of running away or peering suspiciously at me, some of the chimpanzees would climb into the trees and rock the branches, glaring at me in silence.
Those silent "displays," as modern scientific zoologists call them, were still tinged by fear, and it was many months before the chimpanzees were sufficiently unafraid to react with real aggression. It happened for the first time when I was following a group in thick forest. The chimpanzees had stopped calling when they heard my approach, and I paused to listen, unsure of their whereabouts.
A branch snapped in the undergrowth right beside me, and then I saw a juvenile sitting silently in a tree almost overhead, with two females nearby. I was right in among the apes. I sat down. Then I heard a low "huh" from a tangle of lianas to my right, but I could see nothing. Then came another "huh" behind me, and another in front.
Curiosity Prompts an Attack
For about 10 minutes these uneasy calls continued. Occasionally I made out a dark shape in the undergrowth, or saw a black hand clutching a liana, or a pair of eyes glaring from beneath black, beetling brows.
The calls grew louder, and all at once a tremendous bedlam broke out—loud, savage yells that raised the hair on the back of my neck. I saw six large males, and they became more and more excited, shaking branches and snapping off twigs. One climbed a small sapling right beside me and, all his hair standing on end, swayed the tree backward and forward until it seemed he must land on top of me. Then, quite suddenly, the display was over and the males began to feed quietly beside the females and youngsters.
On one occasion I was actually hit by a chimpanzee in the wild, but this was prompted by curiosity rather than aggression.
I was waiting near a ripe fruit tree when I heard footsteps in the leaves behind me. Not wanting to startle the apes, I lay down, hoping that they would reach the fruit tree without seeing me. But the footsteps stopped, and I heard small, high-pitched sounds behind me: "Hoo! Hoo!" The inflection told me the chimpanzees were surprised or uneasy.
I did not move, and suddenly a mature male climbed into the tree above me and sat, scarcely 10 feet over my head, peering down at the strange object below. I think he was puzzled by my immobility and by the sheet of polyethylene protecting me from the rain.
He worked himself into a rage, hitting the trunk and shaking the branches. His small hoots became louder until, with mouth wide open to show yellow canines, he was uttering high-pitched, choking screams of anger.
Still I did not move. Through the corner of my eye I could see three others watching.
All at once the male disappeared, and I heard him moving in the leaves behind me. There was a silence and then, with a loud scream, he rushed forward and I felt the slam of his hand on the back of my head.
The experiment had gone far enough—the fate of the African who had lost an eye and half his cheek in an encounter with an angry chimpanzee came to mind. Slowly I sat up, and at last the ape realized exactly what I was. He moved away with his companions, still brave from his passion, calling out and drumming on the trees.
Later I talked with Dr. Leakey about the incident-and was thankful I had made no sudden moves or cries that would have further enraged the chimpanzee.
"If you had waved your arms, shouted, or shown anger in any way," he said, "you might have been killed. He was merely testing to find out if you were an enemy or not."
Gradually, during the months of my study, the apes became less aggressive, until finally I was greeted almost as another chimpanzee—sometimes by a show of excitement with hooting and shaking of branches, and sometimes by a complete lack of interest.
On the whole the chimpanzees merely tolerated me, but one, a mature male in the prime of life, went a stage further, and tolerance became friendship. David Greybeard—he deserves an article to himself.
It was during the eighth month of my research, when the fruit was ripe on one of the oil palms outside my tent, that David paid his first visit to camp. Dominic told me about it when I got down from the mountains that April evening.
The following day I learned he had called again, and so I determined to wait in camp to try to see him. I recognized him at once from having seen him in the forest; he had always been particularly unafraid of me there.
He visited camp almost every day for about a week, and then the nuts were finished and he stopped coming.
David Provides a Wonderful Moment
When more palm nuts ripened, however, David again visited us. Even in those early days he sat feeding calmly while I walked about under the trees. I discovered that he liked bananas too and left a few out for him.
Gradually he became tamer and tamer, but it was not until the last five months that David showed complete confidence in his human friend. Two of the palms in camp were ripe, so I got in a great supply of bananas and devoted myself to David for a whole week.
After three days he actually took a banana from my hand. It was a wonderful moment. He was apprehensive when I held it out. He stood up and hit the trunk of a tree, rocking slightly from foot to foot. But when he took the fruit there was no snatching—he was amazingly gentle from the first. Friends in the Forest, Too
After that I began carrying a couple of bananas with me up in the mountains, and when I met David he would come up and take them, sitting close beside me, to the astonishment of his companions who gazed wide-eyed at the behavior of their fellow ape! Even when I had no bananas David would come to sit beside me for a moment, with a soft "hoo!" of greeting.
Soon David began popping into camp any old day, whether there was a palm with fruit or not. Dominic and Hassan were both delighted and would describe David's visits in detail when I returned, from the mountains in the evenings.
Best of all, David began to bring two friends along, Goliath and William. At first they were shy and watched from the safety of the trees, but eventually the sight of David sitting and stuffing himself was too much for them, and they rushed out to grab a share of the bananas. Ultimately they became as tame as David, and I was able to treat the three in a way few people would care to treat a mature chimpanzee in captivity.
Clothes and Blankets Disappear
In addition to their love for bananas, David and his friends had a passion for sucking material—old clothes and greasy cloths from the kitchen were the most sought after. David went off with a good many blankets, as well as shirts and other garments, and Goliath took many tea towels, but it was William who was the real thief.
William looked for things to steal, and Dominic, as soon as he saw him approach, would rush off to protect the washing and watch over the tents.
But there were many days when William's arrival went unnoticed, and finally my wardrobe was reduced to one pair of shorts and two shirts. All my blankets had, at some time or another, been rescued from the trees where William had abandoned them.
Chimpanzees show as much individuality as man himself, and David, Goliath, and William have very different characters. David has an exceptionally calm disposition and an air of natural dignity. He takes life as it comes, moving leisurely from place to place, and is always trying to calm the excitable Goliath.
Goliath, with his massive shoulders and bull neck, could easily be taken for a gorilla at first glance. He is wild, impetuous, and inclined to violence; all his movements are vigorous, whether he is swinging down from a tree or charging off to meet a friend.
His large size and uncertain temper make him well respected by the other chimpanzees. When he leaps into a tree to join a group, there are wild screams as the hitherto peaceful chimpanzees scatter in all directions. He is the only male I have seen actually attacking a female, and on one occasion he even drove a young ape from its nest, which he then appropriated, bending in a few more branches and settling down with great satisfaction.
Angry Goliath Brandishes Ax
When I refused to give Goliath more bananas, he became tremendously excited and rushed about slapping the ground or tearing off branches and waving them in the air. Once when I withheld the fruit, he charged after Dominic's wife, seizing an ax that was lying nearby and brandishing it over his head. He probably had no intention of using it as a weapon. It was simply a means of expressing his frustration; he calmed down at once when I went up to him with a banana.
William—well, William is just William. With his long, scarred upper lip and his long, drooping lower lip he is the clown of Chimpland. Yet he is a rather pathetic individual under his clownishness. In the early days when he sat watching David eat bananas and dared not approach, he would rock himself quietly from side to side, occasionally saying sadly, "Hoo! Hoo!" Once or twice he was a little more active, rocking branches and snapping twigs, but he never gave a display like Goliath's.
Even in health William is a sad figure, with his bony hips, his broken finger, his curled-up, slightly deformed feet, and his scars. Such scars and deformities are rare to my knowledge, though I have seen other broken fingers.
Once when William had a dreadful cold, he slept in the same nest for three nights, a most unusual procedure (page 283). Each night it poured rain, and when he climbed down in the morning he was shivering violently, and coughing and wheezing so that I longed to give him a hot toddy instead of a cold banana.
Chimpanzees often call out if it rains during the night. They sit up in their nests, hunched forward over their knees with heads bent down, and wait until the rain stops. I never observed them attempting to make a shelter or to take advantage of any natural one.
Rains Make Grass 12 Feet High
Rainfall in the Kigoma area is heavy, and the rainy season, which starts with the "short rains" in October, carries on without a break into the "long rains," which last until May.
At the start of the short rains, the mountains are at their most beautiful, with green grass pushing up through the black volcanic soil, and flowers, many of them exquisitely lovely, appearing overnight.
Gradually, however, it becomes hard to move through the mountains. The grass, razor sharp and always drenched by rain or dew, shoots up to 12 feet or more all over the reserve, and traveling along the overgrown tracks is no joke. Once I came within 10 yards of a bull buffalo who was lying down dozing. Luckily I was downwind and he never knew I was there.
Keeping equipment dry is a never-ending battle. Water condenses in binoculars, camera lenses mist over, and everything is permanently thick with mildew.
In addition, when I am moving about through grass taller than my head, it is difficult to see anything. In order to continue my observations, I have to climb trees. Thus, as the rainy season progresses, my own habits become increasingly arboreal!
December brings the departure of the last of the fishermen permitted in the reserve, and my evening clinics, which consist mainly of handing out aspirin, Epsom salts, antimalaria pills, or adhesive tape to the inevitable visitors to camp, are considerably reduced. These clinics, started by my mother when we first arrived at the reserve, were a tremendous help in establishing and maintaining friendly relations with the Africans.
My most faithful patient was eight-yearold Jamanne (page 290). He always managed to think up some complaint, and was happiest when he could produce a minute scratch and demand a strip of adhesive tape. But his chief delight lay in helping me, handing out the medicine and explaining to the fishermen in the most superior manner how they should take it.
During the rains the chimpanzees tend to go to bed earlier and get up later, and when they rest during the day they often make themselves a day nest in a tree rather than lie on the cold, damp ground.
At these times infants still sleeping with their mothers at night make little nests as a sort of game, and very instructive play it is. An infant of about eighteen months finds it difficult to bend in even a couple of twigs; each time it reaches out for a second one, the first springs up again. But by the time the young one is ready to sleep alone, it has mastered the nest-making technique.
Rain Incites a Violent Ritual
Generally speaking, chimpanzees become more active during the rains and often, for no apparent reason, a male will break into a run, slapping the ground or hitting out at a low branch as he passes. This behavior, when large groups are present, may develop into a fascinating display which I have called the "rain dance."
I saw it on four occasions, always about midday and always in similar terrain. In every instance it followed the same pattern, but the duration varied from 15 to 30 minutes. It did not always take place in the rain, but rain was falling hard the first time I saw it.
I was watching a large group of chimpanzees, 16 in all, feeding and playing in a tree halfway up the opposite slope of a narrow ravine. Rain had been threatening all morning and finally it came down, gently at first, becoming gradually heavier.
When the rain started, the chimpanzees climbed down from the tree one by one and sat for a while on the ground before starting off up the grassy slope.
They had divided into two groups, with four large males in one group and three in the other. As they neared the ridge at the top, one of the males suddenly turned and charged diagonally downward, slapping the ground, calling loudly, and hitting at a tree as he passed. At once a male from the other group turned and began to run down the slope. Standing upright, he tore a low branch from a tree, waved it for a moment, and then dragged it behind him as he ran.
Meanwhile the females and juveniles were climbing trees near the skyline to watch.
At the top of the slope another male stood upright, rocking slightly from foot to foot, his arms swinging, working up momentum.
Then he too was away, charging downward, breaking off a great bough as he went. Two more set off, calling wildly. One after the other they sprang up into a tree and, without a pause, hurled themselves some 25 feet to the ground, tearing off branches as they fell and dragging them on their downward run.
At the bottom, each chimpanzee swung up into a tree to break his headlong rush. There he sat for a moment before climbing down to plod up to the top of the slope once more. Then, with loud cries, he was off again.
Thunder Roars Above Apes' Wild Calls
All the time the rain pelted down, harder and harder, while lightning streaked across the leaden sky and crashing thunder almost drowned the wild calling of the apes. Against the new green grass they looked very black and huge-like primitive, hairy men displaying their strength (painting, pages 298-9).
For about half an hour I watched; and then, as suddenly as it had started, the display was over. The spectators climbed down from their trees, and one by one the chimpanzees wandered up to the ridge and disappeared over the top. The last male paused on the skyline, looking back toward me with one hand on a tree trunk-the actor taking his final curtain. Then he, too, was gone.
Rain seems to have more effect on some chimpanzees than others. Goliath in particular often gets very excited at the start of a rain storm, and once he did a fantastic dance all by himself, swaying rhythmically from foot to foot, tearing down huge branches, and gradually becoming wilder and wilder. William, who was sitting close beside him at the start, paid absolutely no attention.
David Greybeard is inclined to become truculent in the rain. Once during a thunderstorm, when I was sitting on the banana box to try to prevent his taking all the fruit, he came and stood upright in front of me, hooting loudly, with one arm raised above his head. He then danced about, hitting a tree, the box, and finally me.
Chimps and Baboons Sometimes Clash
Occasionally a group of baboons gathers round David while he is eating bananas. Sometimes he ignores them, but often, and particularly when it is raining, he chases them off, swinging his arms and hooting.
The relationship between the chimpanzee and the baboon is complex and interesting. The ape is the larger and more powerful animal, but the baboon is far more numerous and represents the chimpanzee's only serious competitor for food.
For the most part the two species tolerate each other, and it is common to see baboon and chimpanzee feeding in the same tree. On the other hand, I have seen a group of chimpanzees leap out of a tree at the approach of a baboon troop.
On one occasion a fairly young male baboon climbed up into a palm where David and William were feeding and began to taunt William, going up to him, barking and hitting out at him. William hit back and the two fought for a moment. Then both chimpanzees climbed from the tree, leaving the baboon in possession.
Sometimes young male baboons chase after female and juvenile chimpanzees, which rush away screaming. Often one or two male chimpanzees then join in, chasing after the baboons, which flee in turn. These mock battles seem to be a strange mixture of play and aggression.
I once watched a troop of baboons teasing four adult chimpanzees—two males and two females. The male baboons insolently moved closer and closer to the apes-until, all at once, the latter seemed to lose their tempers.
The males stood upright and charged at their tormentors, swinging their arms over their heads. The females leaped to the low branches of a tree and, leaning down, screamed piercingly at the baboons below. I thought a real fight would take place, but after a few moments the male chimpanzees returned from the chase, and both apes and baboons walked peacefully on.
It would seem that the chimpanzee and the baboon tolerate each other because each, to some extent, has respect for the other. But these happy relations do not exist between the chimpanzee and some of his smaller neighbors.
Gombe Chimpanzees Eat Meat
It will be a surprise to many to learn that the chimpanzee in the wild has definite carnivorous tendencies. It has always been suspected by scientists that wild chimpanzees might eat an occasional lizard or small rodent, but no one thought these apes might kill fairly large animals.
As far as I can determine, the fact that they do so came to light for the first time during my research. This behavior may not be common to all races of chimpanzees in Africa, but it is certainly true of those of the Gombe Stream Reserve.
Monkeys seem to be a favorite item on the menu. I saw them eaten on four occasions, and twice I found bits of bone in the chimpanzee droppings. In addition, I once saw a young bushbuck eaten, and another time a young bush pig. Four times the prey was unidentifiable.
I saw chimpanzees eating meat several times before I actually saw them attack and kill. On that occasion the prey was a red colobus monkey. I was watching four of these monkeys resting in a tall, leafless tree when suddenly a young chimpanzee climbed into a neighboring tree. He sat close enough to one of the monkeys to attract its attention, yet not close enough to scare it away. Meanwhile another young chimpanzee bounded up the tree in which the monkey was sitting, ran with incredible speed along the branch, leaped at the colobus, caught it with its hands, and presumably broke its neck.
Five other chimpanzees then climbed up, including a mature male. But because an adolescent had made the kill, the carcass was torn up and shared among the whole group, with no fighting or quarreling.
At other times, however, when the prey is in the possession of a mature male, there is no such sharing. The others in the group show respect. They sit as close to the male as they can, watching the meat with longing eyes, holding out their hands palm uppermost in a begging gesture.
William Pays Price for Grabbing
The reaction of the male to his suppliants varies. Let me describe the time when Huxley was eating a young bushbuck. He was clasping the carcass with one arm, and it was, incidentally, almost as big as himself! Presumably he had broken its neck, just as other chimps had killed monkeys. In his free hand Huxley held a bunch of twigs and after each mouthful of meat he ate a few leaves—for all the world like a man with a lump of cheese and a stick of celery.
Gathered close round Huxley, and all begging, were three other large males-J. B., Hollis, and William. Several times Huxley tore off a piece of meat and put it into the outstretched hand of J. B. Once Hollis begged from J. B. and was rewarded with a small bloody splinter. When a youngster of about four years held out its hand, Huxley, after a moment, very gently cuffed it on the head, but a female with a tiny infant was allowed to feed from the carcass unmolested.
The sight of this female tucking it in proved too much for poor old William, who had been begging and begging in vain. He ventured to help himself to a bite. Evidently it was one thing for the mother to share in the spoil, but quite another when William tried to join in. Huxley at once grabbed William and bit him, at which J. B. came racing down and chased the screaming William from the tree.
There was a good deal of yelling and crashing around in the undergrowth, and then the two climbed back into the tree. They sat near Huxley, who at once hit William four or five times, after which J. B. did the same.
Poor William tried neither to escape nor to retaliate. He simply sat there screaming and took his medicine. And then he reached out to touch the lips of his punishers in the gesture of appeasement, and all was peaceful again. William was not forgiven, however, to the extent of a handout.
Raw meat, though obviously a great delicacy, is only an occasional supplement to the chimpanzee's diet. Whether the apes deliberately set out to hunt for meat, or merely make kills because of opportunity, remains undetermined. I suspect the latter.
The bulk of the diet is, of course, vegetarian. I have collected 81 different types of vegetable foods eaten by chimpanzees, of which half consists of fruits, a quarter of leaves, and the remainder of seeds, blossoms, stems, and bark.
Epic Discovery Reveals a Tool-maker
In addition, however, the chimpanzees sometimes feed on insects-at certain times of the year fairly extensively. I have seen them eating termites, two species of ant, and two types of gall, a tumorlike growth on a leaf in which the young gallfly lives. And it is this method adopted by the chimpanzees for feeding on ants and termites that probably represents the most important discovery in my two years of research.
For a long time there has been heated discussion in scientific circles as to whether any primates in the wild ever modify natural objects to make tools. My chimpanzees have settled the argument once and for all: The answer is that at least some chimpanzees do.
Termites form a major part of the chimpanzee diet for a two-month period. The termite season starts at the beginning of the rains, when the fertile insects grow wings and are ready to leave the nest. At this time the passages are extended to the surface of the termite heap and then sealed lightly over while the insects await good flying weather. The chimpanzee is not alone in his taste for termites-the baboon in particular has a fondness for the juicy insects, but he must wait until they fly and then take his turn, together with the birds, at grabbing the termites as they leave the nest.
The chimpanzee forestalls them all. He comes along, peers at the surface of the termite heap and, where he spies one of the sealed-off entrances, scrapes away the thin layer of soil. Then he picks a straw or dried stem of grass and pokes this carefully down the hole. The termites, like miniature bulldogs, bite the straw and hang on grimly as it is gently withdrawn.
I have watched chimpanzees fish this way for two hours at a time, picking dainty morsels from the straw and munching them with delight. When they don't have much luck with one hole, they open another and try again.
As the straw becomes bent at the end, the chimpanzee breaks off the bent pieces until the tool is too short for further use. Then it is discarded and a new one picked. Sometimes a leafy twig is selected, and before this can be used the chimpanzee has to strip off the leaves.
In so doing—in modifying a natural object to make it suitable for a specific purposethe chimpanzee has reached the first crude beginnings of tool making.
Chimps Carry Tools on Termite Search
In this respect, the chimpanzees do not always await the discovery of a termite nest before seeking a tool. I have seen them break off a twig and carry it for as far as half a mile, going from one termite hill to another, though none at the time was suitable for feeding.
It is unlikely that this practice of fishing for termites is an inborn behavior pattern. Among higher primates, behavior is found to depend more and more on learned techniques and less and less on "instincts." It seems almost certain that this method of eating termites is a social tradition, passed from ape to ape by watching and imitation. As such, it must be regarded as a crude and primitive culture.
We do not know yet if similar traditions have developed among other chimpanzee populations in Africa. The answer may throw interesting light on the spread and development of culture in early man.* Meat in Diet Poses Question
It is equally important to find out whether capture and eating of prey is common to all chimpanzees or peculiar to those of the Gombe Stream Reserve. Perhaps this is simply a local tradition, in which case there is always the possibility that it might develop and eventually involve more elaborate hunting techniques.
At present these chimpanzees appear merely to take advantage of any good opportunity that presents itself for the killing of prey-as was perhaps the case with early man. It seems important that in the future recurring observations should be made of the meateating and hunting behavior of this chimpanzee population.
In the chimpanzee, there is reason to speculate that overspecialization has not led to an evolutionary dead end, as may be the case with the other great apes. Of course, if the forests of Africa were cleared for agriculture, the chimpanzee would not survive in competition with man. But if the forests gradually disappeared due to changing climate or similar causes, I think it is interesting to conjecture that the chimpanzee, with his primitive hunting and tool-using, might have a chance of survival, a chance of adapting himself to the new conditions.
There is still much to learn about the behavior of the free-ranging chimpanzee. I am returning to the Gombe Stream Reserve for a further six months, again with the generous support of the National Geographic Society. After that I hope to make behavior studies in other parts of Africa, because, until we have sufficient comparative data, we cannot tell if the behavior of the Gombe Stream chimpanzees differs from those in other regions. Only after we have such data can we draw far-reaching conclusions about the way of life of the chimpanzee, which with the other great apes is the most nearly human of all the animals inhabiting the earth today.