- Shopping Bag ( 0 items )
Sudden in a shaft of sunlight Even while the dust moves There rises the hidden laughter Of children in the foliage.
T. S. Eliot, Four Quartets
Apes are distinguished as being among the very few items on the menu capable (before preparation) of laughter as an expression of mirth.
I first heard an ape laugh while walking in the great Taï Forest of Côte d'Ivoire, in West Africa. Primate researcher Christophe Boesch and I followed a group of wild chimpanzees as they moved on their daily circuit, a complex progression from food to food to food, from obscure fruits to tender herbs to hard nuts.
The chimpanzees in this part of West Africa possess a stone and wood technology, striking hammers against anvils to crack otherwise uncrackable nuts. The hammers can be artificially rounded, quite heavy stones; the anvils may be flat stones with deeply worn pockets. Alternatively, the hammers and anvils may, as they did in this case, consist of rough pieces of hardwood left lying at convenient places beneath productive nut trees. Whenever the chimps we followed came to small groves of ripe nut trees, they stopped to gather handfuls of fallen nuts from the ground, walked and carried them in their hands, and then sat or squatted down in front of their hardwood tools. Christophe and I observed these wild apes lean and hunch intently over their labors. We watched them crack open very hard African walnuts (Coula edulis), hefting heavy hammers made from branches and logs and pounding the nuts, which were carefully positioned in grooves and pockets and crotches of the hardwood anvils. Having cracked and then eaten their fill of the nut meat, these apes left the hammers next to the anvils and moved on.
That day's journey was (for me at least) disorienting. I had no sense of direction and little of distance, and the apes regularly appeared and disappeared from sight, proceeding sometimes individually and sometimes in pairs or small groups. At one point, a group large enough to seem like a migrating herd (who knows how many?) stopped at midday for a siesta and spread out around the gray corpse of a giant tree that had collapsed and broken a hole in the forest canopy. A shaft of sunlight pierced the hole and poured bright yellow onto the forest floor, onto the fallen tree and the bushy space around it, and onto the chimps as well, who were sacked out in the sun, faces turned up to the warmth like holiday sunbathers on a beach. After that midday siesta, the chimpanzees roused themselves and continued on their migration, examining a swampy area for apparently tasty plants, climbing trees looking for fruits, and resting from time to time.
Once, during a resting period, I sat next to a bush that shook with what was undeniably laughter: gleeful and hoarse and breathy, with an edge of frantic, side-splitting desperation. It was entirely like human laughter minus the vocalized overlay, as if a person without a voice box had just thought of something impossibly hilarious. I heard gasping and panting with a hoarse kind of wood-sawing sound: whuuu, whuuu, whuuu. The bush opened, and I saw two juvenile chimps inside, wrestling, tumbling, chasing, teasing each other, and laughing their heads off.
I have observed chimpanzee laughter at other times, in other places. I once watched a grizzled old male chase a juvenile male around a tree, with the little one laughing in delight while the old guy pursued and caught him, playfully biting at his foot and tickling him. I have seen wild-born, orphaned bonobos and gorillas laugh, once again seemingly as a frantic expression of delight and mirth. And I have been told by experts that orangutans, too, sometimes laugh.
Animal play is not surprising. Lion cubs play. Wolves and dogs and dolphins play. Many animals play, especially when they are young. I can believe that many animals experience pleasure. It is possible to imagine that some animals experience something we might call "mirth" or perhaps an irrepressible sensation of emotional lightness. But laughter? The famed ethologist Konrad Lorenz once suggested that dogs "laugh," based on his observations of facial expressions during moments of canine delight. But the laughter of apes is entirely different from any mere facial upturn of pleasure. Neither is it even remotely comparable to the high-pitched vocalizations of hyenas that have on occasion been described as "laughter" but are completely unassociated with play or pleasure.
As with "the hidden laughter of children in the foliage" in T. S. Eliot's Four Quartets, my own experience of the laughter of apes thus becomes that awkwardly articulated moment in an expedition at once physical and metaphysical. Laughter must be among the most fragile and fleeting of vocal utterances. What does it mean? That apes laugh is undeniable. That their laughter means anything is a matter of opinion.
The laughter of apes occurs most often during direct physical encounters, such as a chase-andtickle game. But according to Jane Goodall, who has studied wild chimpanzees in East Africa for the last forty years, "even removed and comparatively complex events can induce chimpanzee laughter." Laughter may happen without any direct physical contact-during a chase without the tickle, for instance, perhaps in anticipation of the tickle. Goodall has observed laughter in much more complicated circumstances, as when one chimp observes another's discomfort. Older chimpanzees sometimes tease their younger siblings with a twig in a tug-ofwar game; the older one may repeatedly pull the twig away from the younger one and laugh at the frustration induced. In one case, Moeza teased her younger brother Michaelmas with a play twig, and finally scampered into a higher place in a tree where Michaelmas was afraid to follow. When the younger sibling screamed in frustration, Moeza, according to Goodall, "gave soft chuckles as she watched his fury."
The laughter of apes provokes us to consider the possibility of an underlying complexity of cognition and intellect, to wonder about the existence of an ape mind. Laughter, in this sense, seems akin to the fascinating and peculiar capacity to recognize oneself in a mirror, an ability shared by humans and apes but not by monkeys. The classic test was first conducted by American psychologist G. Gordon Gallup, Jr., who in the late 1960s demonstrated that four apes (chimpanzees) knocked out with an anesthetic and then marked on the forehead and one ear with a spot of odorless, tasteless red dye would, when awakened and confronted with a mirror, reach up and touch the red spots on their own faces. Six monkeys, similarly marked and faced with a mirror, continued to treat the mirrored image as a vision of some irritatingly provocative member of their species, threatening and vocalizing at the image. Gallup concluded that he had shown a "decisive difference between monkeys and chimps," and that chimps were thus experimentally shown to have a "self-concept."
Charles Darwin postulated a strong evolutionary continuity between apes and humans, and suggested that apes might therefore possess humanlike emotions, memory, and reasoning. But biologists after Darwin less enthusiastically concluded from the available evidence (mostly in comparative anatomy and paleoanthropology) that the ancestors of Homo sapiens diverged from the line that also produced the four modern great apes some 20 million years ago. Even on the evolutionary calendar that's a long time ago-so long ago, the thinking went, that the continuities between human and ape might prove not so interesting. So humans and apes were considered close relatives who had evolved independently for so long that the relationship between modern humans and modern apes could best be described as that of remote cousins. Based on that reasoning, until a couple of decades ago humans were assigned their own special taxonomic family, the Hominidae, while the great apes were comfortably ensconced in theirs, the Pongidae.
Starting in the 1970s, however, laboratory techniques for manipulating the genetic molecule known as DNA advanced to the point where it became possible to look at evolutionary relationships between species far more precisely than ever before. As a result of the last few decades of careful genetic studies, scientists now recognize that the apes are not merely our nearest relatives but nearer to us than anyone had ever imagined.
Orangutan genetic material shows itself to be 96.4 percent identical to human genetic material, which indicates (calculating from a schedule of likely rates of DNA change) that ancestral orangutans split off from the larger ape line approximately 12 million years ago, leaving the ancestral group of the three modern African apes (gorillas, chimpanzees, and bonobos) and humans still evolving together as a single genetic lineage.
Modern gorilla DNA is 97.7 percent the same as that of humans, indicating that their line started to evolve independently around 7.5 million years ago. And modern chimpanzee and bonobo DNA turns out to be around 98.7 percent identical to that of modern humans, which suggests that ancestral humans split away from the line that produced chimpanzees and bonobos around 6 million years ago.
The DNA data show that apes evolved closely as a group and that humans remained part of that group until the first human precursors stepped out into their own evolutionary experiment only 6 million years ago. And the mere 1.3 percent difference between humans and the chimpanzees and bonobos means that we are actually closer to them than zebras are to horses, or African elephants are to Indian elephants.
In more practical terms, those numbers mean that the next time you go to the zoo and wander past cages containing chimpanzees or bonobos, you might pause and look into the eye of a being who will indeed look back; and you should know that you (genetically almost 99 percent chimpanzee) are sharing a gaze with someone who is, according to the best measurement, almost 99 percent human. You are on one side of the bars, the chimps and bonobos on the other side, simply because those apes lack a little more than 1 percent of the requisite genes to be treated like humans. And if you linger to gaze at gorillas in the same zoo, remember that they are sitting on the other side of the bars or the moat not because they have done anything wrong, but simply and solely because they happen to be missing just slightly more than 2 percent of the human genome.
Structurally, the brains of humans exactly resemble the brains of the nonhuman apes, except in size. The largest gorilla brain on record, around 690 cubic centimeters in volume, still is smaller than the smallest known adult human brain, measured at about 790 cubic centimeters. Simply comparing average brain size suggests intellectual differences between human adults and adults of the other ape species. On the other hand, the fact that an adult chimpanzee brain is distinctly larger than the brain of a human child evokes the possibility of overlapping mental qualities.
Cranial capacity is not the same as intellectual capacity, however, and it remains a commonplace act of self-flattery for people to persist in emphasizing that great divide between the intellect of humans and the other apes. Why should we, the makers of such wondrous things as automobiles and computers and atomic bombs, be impressed by them, the makers of mere nutcrackers and termite dippers? We continue to mark not similarity but difference, as if the distinction between us and them is a matter of our own species' pride. Homo sapiens may possess some superficial similarities with Pan troglodytes, it has been declared again and again, but the mental divide between the two species remains uncrossable. "I considered the differences between men and animals," so journalist Jeremy Gavon has recently expressed the idea. "Some were vast. A chimpanzee could be taught to drive a car. It could even be taught to build parts of it. But it could not begin to design it.... Our intellect is incomparably more sophisticated than any animal."
True, a chimpanzee could not begin to design a car. But, come to think of it, neither could I. Nor could you or any other person working in intellectual isolation-without the help of books, conversations, directions, documents, explanations, and traditions-design a car. Or even a bicycle. Or a pair of shoes. Or a mousetrap. Apes work in intellectual isolation because they lack language. We have language, and therefore our creations and inventions and technologies become collective efforts and cultural products. No one person designed or invented the automobile. Automobiles derive from earlier transportation technologies, and from power and metallurgic technologies that go back as far as the first tool that turned the first wheel and the first fire that smelted the first piece of shiny metal. Nor did one brilliant person hiding in a garage in northern California invent the personal computer. Computers appeared as the consequence of developments in the Chinese abacus, ninth-century Arabic mathematics, the eighteenth-century jacquard loom, nineteenth-century mechanical office machines, twentieth-century electronics, and so on. Bicycles were not possible before bicycle wheels; bicycle wheels were inconceivable before spokes; spokes were impossible before spokeshaves. None of the technologies that have elevated our own species into a position of planetary mastery has been created by an individual person working in isolation and inspired solely by the brilliance of an intellect that is "incomparably more sophisticated" than that of the apes. With your brain alone, with my brain alone (minus language and a language-based tradition), we would consider ourselves very lucky indeed to think of cracking nuts between a stone hammer and a stone anvil. Our greatest human creation is not the tool but the word, not the technology that we so treasure and depend on but the language that has allowed us to talk about it. Language, not technology, is the most compelling artifact of the human intellect.
Excerpted from Eating Apes by Dale Peterson Copyright © 2003 by Regents of the University of California.
Excerpted by permission. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
|App. A||Saving the Apes||231|
|App. B||Further Reading||240|
|App. C||The Primate Family Tree||243|
|App. D||The HIV/SIV Family Tree||244|