Shadows of Forgotten Ancestors (42 page)

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Authors: Carl Sagan,Ann Druyan

BOOK: Shadows of Forgotten Ancestors
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They’re a little shorter, somewhat hairier, much stronger, and a lot more sexually active than most humans are. They have brown hair and brown eyes. In their natural habitats, they may live to be forty or fifty years old—which is longer than the average in any human society before the Industrial and Medical revolutions. But their average life expectancy is much less. Unlike modern humans, females past infancy are not likely to live as long as males. They alternate between walking on two feet and on all fours, using their knuckles. Chimpanzee males tend to have short fuses. They give off a faint but characteristic odor when they’re nervous or excited, revealing emotions they sometimes try to hide. Chimps are not ashamed of displaying their sexual parts. By our lights they’re a lot dumber than we are, but they do use and even make tools. They apparently hold grudges, nurse resentments, and harbor thoughts of revenge. They plan future courses of action.

Family ties may be strong and lasting. Aged mothers will rush to the defense of their children, even full-grown sons. Orphaned infants are tenderly raised by older siblings. They experience prolonged grief at the loss of a loved one. They suffer from bronchitis and pneumonia,
and can be infected with almost any human disease, including the AIDS virus. The elderly turn gray, get wrinkles, lose teeth and hair. Chimps get drunk. They’re able to learn more words of a human language than we have of any chimp language. When they look in the mirror, they recognize themselves. They are, at least to some degree, self-aware. Infants get cranky and irritable when they’re weaned. Chimps form friendships, often with comrades-in-arms who hunt together and guard their turf against intruders. They share food with relatives and friends.

When raised among humans, they have been known to masturbate to pictures of naked people. (This is probably true only of those who, through prolonged contact, have come to consider themselves human. Wild chimps would no more masturbate to erotic images of humans than vice versa.) They keep secrets. They lie. They both oppress and protect the weak. Some, despite many setbacks, persistently strive for social advancement and career opportunities. Others, less ambitious, are more or less content with their lot.

Among much other innate knowledge, they are born with an understanding about how to make a bed of leaves each night up there in the trees. They are much better climbers than we, partly because they haven’t lost, as we have, the ability to grasp branches with their feet. The youngsters love to climb trees and rival one another in spectacular feats of gymnastic derring-do. But when an infant has climbed too high, its mother—socializing with her friends at the base of the tree—decisively taps the trunk and the baby obediently scampers down.

The forest is crisscrossed with a network of trails made by generations of chimps going about their daily business. Each knows the local geography at least as well as the average human city-dweller knows the neighborhood streets and shops. They almost never get lost. Here and there along the trails are trees with acoustically resonant trunks. When a party of foragers spies such a tree, many run forward and drum away—both sexes, children as well as adults. There are no strings, woodwinds, or brass yet, but the percussion section is in place.

Chimps recognize one another’s individual voices, and a distinctive pant-hoot may summon an ally or relative from a considerable distance. In answering a pant-hoot from, say, an adjacent valley, they lift their heads and purse their lips as if they were on stage at La Scala. Up close, they have an uncanny ability—“uncanny” means only that
we haven’t been smart enough to figure it out yet—to communicate with one another, not just about such straightforward matters as sex or dominance, but about much more subtle matters, such as hidden dangers, or buried food supplies. A classic set of experiments was done by the psychologist E. W. Menzel:

[Menzel] maintained four to six young chimpanzees in a large outdoor enclosure that was also connected to a smaller holding cage. He restrained all but one animal in the holding cage, while showing this chosen “leader” the hidden location of either an amount of food or an aversive stimulus such as a stuffed snake. The leader was then returned to the holding cage, and the whole group was released. According to Menzel’s reports, the variable behavior of the animals indicated that they “seemed to know approximately where the object was, and what sort of object it was, long before the leader reached the spot where it had been hidden” … If the goal was food, they ran ahead looking in possible hiding places; if it was a stuffed alligator or snake, they emerged from their cage showing piloerection [their hair standing on end] and staying close to their companions. If the hidden item was an alligator or snake, they became very cautious in their approach and often mobbed the area, hooting in the direction of the hidden item and hitting at it with sticks. If the hidden item was food, the animals searched the area intensively and showed little fear or distress. The behaviors occurred even if the aversive stimulus had been removed before the animals were released from the holding cage, so it was not the item itself that produced these reactions.

In the food tests, one male (Rocky) began to monopolize the food supply when it was located. When Belle, a female, served as leader, she attempted to avoid indicating the location of the food cache, but Rocky could often extrapolate from her line of orientation and find the food. If Belle were shown two caches, one large and one small, she would lead Rocky to the small one and, while he was busy eating, run to the larger one which she would share with other individuals. Menzel concluded that chimpanzees could communicate the direction, amount, quality, and nature of the goal, as well as attempt to conceal at least some of this information, but precisely how chimpanzees achieve such communication is still not known.
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The only possibilities seem to be gestures and speech.

Chimps have hundreds of different kinds of food and crave dietary
variety. They eat fruit, leaves, seeds, insects, and larger animals, sometimes dead ones. Caterpillars are delicacies, and the discovery of an infestation of caterpillars becomes a memorable gastronomic event. They’re known to eat soil from cliff faces, presumably to provide mineral nutrients such as salt. Mothers will offer choice tidbits of food to their infants and will snatch unusual, possibly dangerous, foods from their mouths. In the wild, adults share food occasionally, often in response to begging. There are no set mealtimes; they snack throughout the day. As a foraging party moves on, one of its members may carry a branch still laden with berries or leaves to munch as she rambles.

When in the middle of the night, in their beds of leaves in the high branches, they are awakened by the cries of predators, they clutch each other in fright, their urine and feces raining down on the forest floor below.

They love to play, children (whose energy is prodigious) more than adults, but even adult play is common—especially when there’s enough to eat and large numbers of chimps gather together. Play often involves, but is not restricted to, mock fighting.

Chimp males are protective toward females and the young. They will readily risk their own lives to protect “women and children” from attack, or to rescue a youngster in trouble. Goodall writes, “Often it seems that a male cannot resist reaching out to draw an infant into a close embrace, to pat him, or to initiate gentle play.”
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When a male is discovered
in flagrante delicto
with a female, which is often, an infant may rush up to punch the male in the mouth or jump on the back of the female, most often his mother.
*
In such situations the male’s tolerance frequently exceeds human limits.

But in a display competition for dominance, all this good-natured equanimity vanishes, and a male who ordinarily is protective of infants may pick up a small, innocent bystander and slam it to the ground in his rage. When an unfamiliar female is discovered in their territory,
chimps are known to seize her infant by the ankles and smash it against the rocks.
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Chimps tend to pick on the runt of the litter, and to displace their own anger away from higher-ranking chimps (who might do them harm) to those who are milder-tempered, younger, weaker, and female. At Gombe in 1966 there was a polio epidemic which resulted in the partial paralysis of full-fledged members of the group. Crippled by their disease, they were forced to move in odd ways, dragging limbs. Other chimps were at first afraid; then they threatened the afflicted, and then attacked them.

Because aggression is episodic and friendly relations so much more common, some early field observers were tempted by the notion that chimps in a state of nature (that is, unimprisoned) are non-violent and peace-loving. This is not the case. In hunting other animals, in working the dominance hierarchy, in hustling the females, in peevish moments, and in skirmishes with other groups of chimps (the Strangers, in our narrative), they show themselves capable of great violence.

Meat contains essential amino acids and other molecular building blocks more difficult to acquire from plants. Both sexes are ravenous for meat. On rare occasions, females will attack other females in their group and steal and eat their infants. Once the little one is in hand, there are no ill feelings directed to the mother of the tiny victim. In one case, a female approached those who were eating her baby; one of the diners responded by putting out her arms to embrace and comfort the grieving mother. Chimps are known to hunt mice, rats, small birds, a twenty-kilogram adolescent bush pig, monkeys such as baboons and colubuses, and other chimps.

A successful hunt is accompanied by enormous excitement. The spectators scream, hug, kiss, and pat one another reassuringly. Those actually involved in the kill immediately begin feeding, or attempt to carry off tasty body parts. The forest is filled with screeches, barks, pants, and hoots—which attract additional chimps, sometimes from a considerable distance. Generally males help themselves to bigger portions than females. Those of high rank are more likely to distribute the spoils, and one way or another most who are actually present at the kill gain a share. Newcomers plead for morsels. Pieces will be stolen, and the chimp whose prize has been taken will be furious, perhaps indulging in a temper tantrum. Portions of meat are taken to bed for midnight snacks.

A rat may be eaten head first. A monkey or young antelope is often killed by having its head smashed against a rock or tree trunk, or by giving it a vampirish bite in the back of the neck. Almost always the brains are eaten first. This is often the prize of the hunter who performs the actual kill. Other tasty body parts include the genitals of male victims and the fetuses of pregnant female victims. Goodall reports the final, attenuated, scream of a young bush pig as a chimp, like some ancient Aztec priest, tore out its living heart. Cooking has not yet been invented, nor flatware, nor table manners, nor squeamishness. This is a world of red blood and raw meat.

Janis Carter describes
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a juvenile chimp and a colubus monkey, about its own size, grooming one another; but when the colubus is seized by the tail and killed by a passing adult chimp, who bashes its head against a tree, the juvenile readily enough joins in devouring its erstwhile playmate. Most of the monkey (and small mammal) victims of chimp predation are infants and juveniles, often snatched from their mothers’ arms. Sometimes the mother tries to rescue the infant and is herself eaten.

In this world there is no mercy shown to food, even if it’s still ambulatory. Food is for eating. Those who are moved to mercy eat less and leave fewer offspring. Clearly the chimps do not recognize monkeys, or chimps of other groups, or even members of their own group as deserving of mercy or other moral considerations. They may be heroic in defending their own young, but they do not show the least compassion for the young of other groups of species. Perhaps they consider them “animals.”

Hunting is a cooperative endeavor. Cooperation is essential for making the larger kills—and also for avoiding their dangers, such as an enraged bush pig charging, tusks first, to save its young. The hunters exhibit real teamwork. One chimp may softly call to another when it has detected prey in the underbrush. They smile to one another. The victim is flushed out of its cover toward other chimps who are lying in wait. Escape routes are blocked off. Ambushes are refined. Plays are called. The chimps—so passionate after the kill—were coolly planning it all out beforehand.

——

 

In densely forested habitats, the territory controlled by a given chimpanzee group is only a few kilometers wide. In sparsely wooded
regions, it can be as much as thirty kilometers across. These are the territories that a chimp group considers its turf, its home, its fatherland or motherland, to which something like patriotic sentiments are owed. It is not to be trespassed by strangers. It’s a jungle out there. The typical day range of a chimp combat patrol is a few kilometers. So if they live in heavy forest, they can fairly readily patrol a good portion of the border in a single day. But if the vegetation and food supply are more sparse and their territory accordingly larger, it may be a few days’ journey from one end to the other, and longer if they go around the perimeter.

A patrol is typified by cautious, silent travel during which the members of the party tend to move in a compact group. There are many pauses as the chimpanzees gaze around and listen. Sometimes they climb tall trees and sit quietly for an hour or more, gazing out over the “unsafe” area of a neighboring community. They are very tense and at a sudden sound (a twig cracking in the undergrowth or the rustling of leaves) may grin and reach out to touch or embrace one another.

During a patrol the males, and occasionally a female, may sniff the ground, treetrunks, or other vegetation. They may pick up and smell leaves, and pay particular attention to discarded food wadges, feces, or abandoned tools on termite heaps. If a fairly fresh sleeping nest is seen, one or more of the adult males may climb up to inspect it and then display around it so that the branches are pulled apart and it is partially or totally destroyed.

Perhaps the most striking aspect of patrolling behavior is the silence of those taking part. They avoid treading on dry leaves and rustling the vegetation. On one occasion vocal silence was maintained for more than three hours … [When] patrolling chimpanzees return once more to familiar areas, there is often an outburst of loud calling, drumming displays, hurling of rocks, and even some chasing and mild aggression between individuals … Possibly this noisy and vigorous behavior serves as an outlet for the suppressed tension and social excitement engendered by journeying silently into unsafe areas.
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