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IdeasA History of Thought and Invention, from Fire to Freud
By Peter Watson
HarperCollins Publishers, Inc.Copyright © 2006 Peter Watson
All right reserved.
Ideas Before Language
George Schaller, director of the Wildlife Conservation Division of the New York Zoological Society, is known to his fellow biologists as a meticulous observer of wild animals. In a long and distinguished career he has made many systematic studies of lions, tigers, cheetahs, leopards, wild dogs, mountain gorillas and hyenas. His book, The Last Panda, published in 1993, recorded many new and striking facts about the animal the Chinese call the 'bearcat'. He found that on one occasion a sick panda had gone freely to a human family in the Wolong area, where it was fed sugar and rice porridge for three days, until it recovered and returned to the forest.1
In the late 1960s Schaller and a colleague spent a few days on the Serengeti plain in Tanzania, East Africa, where they made a simple observation which had escaped everyone else. In the course of those few days, they stumbled across quite a lot of dead meat 'just lying around'. They found dead buffalo, the butchered remains of lion kills, and they also came across a few incapacitated animals that would have been easy prey for carnivores. Smaller deer (like Thompson's gazelles) remaineduneaten for barely a day but larger animals, such as adult buffalo, 'persisted as significant food resources' for about four days.2 Schaller concluded from this that early humans could have survived quite easily on the Serengeti simply by scavenging, that there was enough 'ruin' in the bush for them to live on without going hunting. Other colleagues subsequently pointed out that even today the Hadza, a hunter-gathering tribe who live in northern Tanzania, sometimes scavenge by creeping up on lions who have made a kill and then creating a loud din. The lions are frightened away.
This outline of man's earliest lifestyle is conjectural.3 And to dignify the practice as an 'idea' is surely an exaggeration: this was instinct at work. But scavenging, unromantic as it sounds, may not be such a bad starting-point. It may even be that the open African savannah was the type of environment which favoured animals who were generalists, as much as specialists, like a hippopotamus, for example, or a giraffe, and it is this which stimulated mankind's intelligence in the first place. The scavenging hypothesis has, however, found recent support from a study of the marks made on bones excavated at palaeontological sites: animals killed by carnivores do show tool marks but fewer than those butchered by humans. It is important to stress that meat-eating in early humans does not, in and of itself, imply hunting.4
There are two candidates for humankind's first idea, one rather more hypothetical than the other. The more hypothetical relates to bipedalism. For a long time, ever since the publication of The Descent of Man by Charles Darwin in 1871, the matter of bipedalism was felt to be a non-issue. Following Darwin, everyone assumed that man's early ancestors descended from the trees and began to walk upright because of changes in the climate, which made rainforest scarcer and open savannah more common. (Between 6.5 million and 5 million years ago, the Antarctic ice-cap sucked so much water from the oceans that the Mediterranean was drained dry.) This dating agrees well with the genetic evidence. It is now known that the basic mutation rate in DNA is 0.71 per cent per million years. Working back from the present difference between chimpanzee and human DNA, we arrive at a figure of 6.6 million years ago for the chimpanzee-human divergence.5
Several species of bipedal ape have now been discovered in Africa, all the way back to Sahelanthropus, who lived six to seven million years ago in the Djurab desert of Chad and was close to the common ancestor for chimpanzees and humans.6 But the human ancestor which illustrates bipedalism best is Australopithecus afarensis, better known as 'Lucy', because on the night she was discovered the Beatles' song 'Lucy in the Sky with Diamonds' was playing in the palaeontologists' camp. Enough of Lucy's skeleton survives to put beyond doubt the fact that, by 3.4 to 2.9 million years ago, early humans were bipedal.
It is now believed that the first and most important spurt in the brain size of man's direct ancestors was associated with the evolution of bipedalism. (Most important because it was the largest; there is evidence that our brains are, relative to our bodies, slightly smaller now than in the past.) 7 In the new, open, savannah-type environment, so it is argued, walking upright freed the arms and hands to transport food to the more widely scattered trees where other group members were living. It was bipedalism which also freed the hands to make stone tools, which helped early man change his diet to a carnivorous one which, in providing much more calorie-rich food, enabled further brain growth. But there was a second important consequence: the upright posture also made possible the descent of the larynx, which lies much lower in the throat of humans than in the apes.8 At its new level, the larynx was in a much better position to form vowels and consonants. In addition, bipedalism also changed the pattern of breathing, which improved the quality of sound. Finally, meat, as well as being more nutritious, was easier to chew than tough plant material, and this helped modify the structure of the jaw, encouraging fine muscles to develop which, among other things, enabled subtler movements of the tongue, necessary for the varied range of sounds used in speech. Cutting-tools also supplemented teeth which may therefore have become smaller, helpful in the development of speech. None of this was 'intended', of course; it was a 'spin-off' as a result of bipedalism and meat-eating. A final consequence of bipedalism was that females could only give birth to relatively small-brained offspring--because mothers needed relatively narrow pelvises to be able to walk efficiently. From this it followed that the infants would be dependent on their mothers for a considerable period, which . . .
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