The Ascent of Man, Page 3

  That was fifty million years ago, in very round figures. In the next twenty million years, the line that leads to the monkeys branches away from the main line to the apes and man. The next creature on the main line, thirty million years ago, was the fossil skull found in the Fayurn in Egypt, and named Aegyptopithecus. He has a shorter snout than the lemur, his teeth are ape-like, and he is larger – yet still lives in the trees. But from now on the ancestors of the apes and man spent part of their time on the ground.

  Another ten million years on take us to twenty million years ago, when there were what we should now call anthropoid apes in East Africa, Europe and Asia. A classical find made by Louis Leakey goes by the dignified name of Proconsul, and there was at least one other widespread genus, Dryopithecus. (The name Proconsul is a piece of anthropological wit; it was coined to suggest that he was an ancestor of a famous chimpanzee at the London Zoo in 1931 whose nickname was Consul.) The brain is markedly larger, the eyes are now fully forward in stereoscopic vision. These developments tell us how the main ape-and-man line was moving. But if, as is possible, it had already branched again, then so far as man is concerned, alas, this creature is on the branch line – the ape line. The teeth show us that he is an ape, because the way in which the jaw is locked by the big canines is not man-like.

  It is the change in the teeth that signals the separation of the line that leads to man, when it comes. The first harbinger that we have is Ramapithecus, found in Kenya and in India. This creature is fourteen million years old, and we only have pieces of the jaw. But it is clear that the teeth are level and more human. The great canines of the anthropoid apes are gone, the face is much flatter, and we are evidently near a branching of the evolutionary tree; some anthropologists would boldly put Ramapithecus among the hominids.

  There is now a blank in the fossil record of five to ten million years. Inevitably, the blank hides the most intriguing part of the story, when the hominid line to man is firmly separated from the line to the modern apes. But we have found no unequivocal record of that, yet. Then, perhaps five million years ago, we come certainly to the relatives of man.

  A cousin of man, not in the direct line to us, is a heavily-built Australopithecus who is a vegetarian. Australopithecus robustus is manlike and his line does not lead elsewhere; it has simply become extinct. The evidence that he lived on plants is again in his teeth, and it is quite direct: the teeth that survive are pitted by the fine grit that he picked up with the roots that he ate.

  His cousin on the line to man is lighter – visibly so in the jaw – and is probably a meat-eater. He is the nearest thing we have to what used to be called the ‘missing link’: Australopithecus africanus, one of a number of fossil skulls found at Sterkfontein in the Transvaal and elsewhere in Africa, a fully grown female. The Taung child, with which I began, would have grown up to be like her; fully erect, walking, and with a largish brain weighing between a pound and a pound and a half. That is the size of the brain of a big ape now; but of course this was a small creature standing only four feet high. Indeed, recent finds by Richard Leakey suggest that by two million years ago the brain was larger even than that.

  And with that larger brain the ancestors of man made two major inventions, for one of which we have visible evidence and for the other inferential evidence. First, the visible invention. Two million years ago Australopithecus made rudimentary stone tools where a simple blow has put an edge on the pebble. And for the next million years, man in his further evolution did not change this type of tool. He had made the fundamental invention, the purposeful act which prepares and stores a pebble for later use. By that lunge of skill and foresight, a symbolic act of discovery of the future, he had released the brake which the environment imposes on all other creatures. The steady use of the same tool for so long shows the strength of the invention. It was held in a simple way, by pressing its thick end against the palm of the hand in a power-grip. (The ancestors of man had a short thumb, and therefore could not manipulate very delicately, but could use the power-grip.) And, of course, it is a meat-eater’s tool almost certainly, to strike and to cut.

  The other invention is social, and we infer it by more subtle arithmetic. Skulls and skeletons of Australopithecus that have now been found in largish numbers show that most of them died before the age of twenty. That means that there must have been many orphans. For Australopithecus surely had a long childhood, as all the primates do; at the age of ten, say, the survivors were still children. Therefore there must have been a social organisation in which children were looked after and (as it were) adopted, were made part of the community, and so in some general sense were educated. That is a great step towards cultural evolution.

  At what point can we say that the precursors of man become man himself? That is a delicate question, because such changes do not take place overnight. It would be foolish to try and make them seem more sudden than they really were – to fix the transition too sharply or to argue about names. Two million years ago we were not yet men. One million years ago we were, because by one million years ago a creature appears who can be called Homo – Homo erectus. He spreads far beyond Africa. The classical find of Homo erectus was in fact made in China. He is Peking man, about four hundred thousand years old, and he is the first creature that certainly used fire.

  The changes in Homo erectus that have led to us are substantial over a million years, but they seem gradual by comparison with those that went before. The successor that we know best was first found in Germany in the last century: another classic fossil skull, he is Neanderthal man. He already has a three-pound brain, as large as modern man. Probably some lines of Neanderthal man died out; but it seems likely that a line in the Middle East went on directly to us, Homo sapiens.

  Somewhere in that last million years or so, man made a change in the quality of his tools – which presumably points to some biological refinement in the hand during this period, and especially in the brain centres that control the hand. The more sophisticated creature (biologically and culturally) of the last half million years or so could do better than copy the ancient stone choppers that went back to Australopithecus. He made tools which require much finer manipulation in the making and, of course, in the use.

  The development of such refined skills as this and the use of fire is not an isolated phenomenon. On the contrary, we must always remember that the real content of evolution (biological as well as cultural) is the elaboration of new behaviour. It is only because behaviour leaves no fossils that we are forced to search for it in bones and teeth. Bones and teeth are not interesting in themselves, even to the creature to whom they belong; they serve him as equipment for action – and they are interesting to us because, as equipment, they reveal his actions, and changes in equipment reveal changes in behaviour and skill.

  For this reason, changes in man during his evolution did not take place piecemeal. He was not put together from the cranium of one primate and the jaw of another – that misconception is too naive to be real, and only makes a fake like the Piltdown skull. Any animal, and man especially, is a highly integrated structure, all the parts of which must change together as his behaviour changes. The evolution of the brain, of the hand, of the eyes, of the feet, the teeth, the whole human frame, made a mosaic of special gifts – and in a sense these chapters are each an essay on some special gift of man. They have made him what he is, faster in evolution, and richer and more flexible in behaviour, than any other animal. Unlike the creatures (some insects, for instance) that have been unchanged for five, ten, even fifty million years, he has changed over this time-scale out of all recognition. Man is not the most majestic of the creatures. Long before the mammals even, the dinosaurs were far more splendid. But he has what no other animal possesses, a jigsaw of faculties which alone, over three thousand million years of life, make him creative. Every animal leaves traces of what it was; man alone leaves traces of what he created.

  Change in diet is important in a changing species over a time as l
ong as fifty million years. The earliest creatures in the sequence leading to man were nimble-eyed and delicate-fingered insect and fruit eaters like the lemurs. Early apes and hominids, from Aegyptopithecus and Proconsul to the heavy Australopithecus, are thought to have spent their days rummaging mainly for vegetarian foods. But the light Australopithecus broke the ancient primate habit of vegetarianism.

  The change from a vegetarian to an omnivorous diet, once made, persisted in Homo erectus, Neanderthal man and Homo sapiens. From the ancestral light Australopithecus onwards, the family of man ate some meat: small animals at first, larger ones later. Meat is a more concentrated protein than plant, and eating meat cuts down the bulk and the time spent in eating by two-thirds. The consequences for the evolution of man were far-reaching. He had more time free, and could spend it in more indirect ways, to get food from sources (such as large animals) which could not be tackled by hungry brute force. Evidently that helped to promote (by natural selection) the tendency of all primates to interpose an internal delay in the brain between stimulus and response, until it developed into the full human ability to postpone the gratification of desire.

  But the most marked effect of an indirect strategy to enhance the food supply is, of course, to foster social action and communication. A slow creature like man can stalk, pursue and corner a large savannah animal that is adapted for flight only by co-operation. Hunting requires conscious planning and organisation by means of language, as well as special weapons. Indeed, language as we use it has something of the character of a hunting plan, in that (unlike the animals) we instruct one another in sentences which are put together from movable units. The hunt is a communal undertaking of which the climax, but only the climax, is the kill.

  Hunting cannot support a growing population in one place; the limit for the savannah was not more than two people to the square mile. At that density, the total land surface of the earth could only support the present population of California, about twenty million, and could not support the population of Great Britain. The choice for the hunters was brutal: starve or move.

  They moved away over prodigious distances. By a million years ago, they were in North Africa. By seven hundred thousand years ago, or even earlier, they were in Java. By four hundred thousand years ago, they had fanned out and marched north, to China in the east and Europe in the west. These incredible spreading migrations made man, from an early time, a widely dispersed species, even though his total numbers were quite small – perhaps one million.

  What is even more forbidding is that man moved north just after the climate there was turning to ice. In the great cold the ice, as it were, grew out of the ground. The northern climate had been temperate for immemorial ages – literally for several hundred million years. Yet before Homo erectus settled in China and northern Europe, a sequence of three separate Ice Ages began.

  The first was past its fiercest when Peking man lived in caves, four hundred thousand years ago. It is no surprise to find fire used in those caves for the first time. The ice moved south and retreated three times, and the land changed each time. The icecaps at their largest contained so much of the earth’s water that the level of the sea fell four hundred feet. After the second Ice Age, over two hundred thousand years ago, Neanderthal man with his big brain appears, and he became important in the last Ice Age.

  The cultures of man that we recognise best began to form in the most recent Ice Age, within the last hundred or even fifty thousand years. That is when we find the elaborate tools that point to sophisticated forms of hunting: the spear-thrower, for example, and the baton that may be a straightening tool; the fully barbed harpoon; and, of course, the flint master tools that were needed to make the hunting tools.

  It is clear that then, as now, inventions may be rare but they spread fast through a culture. For example, the Magdalenian hunters of southern Europe fifteen thousand years ago invented the harpoon. In the early period of the invention, the Magdalenian harpoons were unbarbed; then they were barbed with a single row of fish hooks; and at the end of the period, when the flowering of cave art took place, they were fully barbed with a double row of hooks. The Magdalenian hunters decorated their bone tools, and they can be pinned to precise periods in time and to exact geographical locations by the refinement of style which they carry. They are, in a true sense, fossils that recount the cultural evolution of man in an orderly progression.

  Man survived the fierce test of the Ice Ages because he had the flexibility of mind to recognise inventions and to turn them into community property. Evidently the Ice Ages worked a profound change in the way man could live. They forced him to depend less on plants and more on animals. The rigours of hunting on the edge of the ice also changed the strategy of hunting. It became less attractive to stalk single animals, however large. The better alternative was to follow herds and not to lose them – to learn to anticipate and in the end to adopt their habits, including their wandering migrations. This is a peculiar adaptation – the transhumance mode of life on the move. It has some of the earlier qualities of hunting, because it is a pursuit; the place and the pace are set by the food animal. And it has some of the later qualities of herding, because the animal is tended and, as it were, stored as a mobile reservoir of food.

  Fossils that recount the cultural evolution of man in an orderly progression.

  Rock painting of a reindeer hunt, Los Caballos Shelter, Valtorta Gorge, Castellon, Eastern Spain. The invention of the bow and arrow came at the end of the last Ice Age.

  The transhumance way of life is itself a cultural fossil now, and has barely survived. The only people that still live in this way are the Lapps in the extreme north of Scandinavia, who follow the reindeer as they did during the Ice Age. The ancestors of the Lapps may have come north from the Franco-Cantabrian cave area of the Pyrenees in the wake of the reindeer as the last icecaps retreated from southern Europe twelve thousand years ago. There are thirty thousand people and three hundred thousand reindeer, and their way of life is coming to an end even now. The herds go on their own migration across the fiords from one icy pasture of lichen to another, and the Lapps go with them. But the Lapps are not herdsmen; they do not control the reindeer, they have not domesticated it. They simply move where the herds move.

  Even though the reindeer herds are in effect still wild, the Lapps have some of the traditional inventions for controlling single animals that other cultures also discovered: for example, they make some males manageable as draught animals by castrating them. It is a strange relationship. The Lapps are entirely dependent on the reindeer – they eat the meat, a pound a head each every day, they use the sinews and fur and hides and bones, they drink the milk, they even use the antlers. And yet the Lapps are freer than the reindeer, because their mode of life is a cultural adaptation and not a biological one. The adaptation that the Lapps have made, the transhumance life on the move in a landscape of ice, is a choice that they can change; it is not irreversible, as biological mutations are. For a biological adaptation is an inborn form of behaviour; but a culture is a learned form of behaviour – a communally preferred form, which (like other inventions) has been adopted by a whole society.

  There lies the fundamental difference between a cultural adaptation and a biological one; and both can be demonstrated in the Lapps. Making a shelter from reindeer hides is an adaptation that the Lapps can change tomorrow – most of them are doing so now. By contrast the Lapps, or human lines ancestral to them, have also undergone a certain amount of biological adaptation. The biological adaptations in Homo sapiens are not large; we are a rather homogeneous species, because we spread so fast over the world from a single centre. Nevertheless biological differences do exist between groups of men, as we all know. We call them racial differences, by which we mean exactly that they cannot be changed by a change of habit or habitat. You cannot change the colour of your skin. Why are the Lapps white? Man began with a dark skin; the sunlight makes vitamin D in his skin, and if he had been white in Africa, it wou
ld make too much. But in the north, man needs to let in all the sunlight there is to make enough vitamin D, and natural selection therefore favoured those with whiter skins.

  The biological differences between different communities are on this modest scale. The Lapps have not lived by biological adaptation but by invention: by the imaginative use of the reindeer’s habits and all its products, by turning it into a draught animal, by artefacts and the sledge. Surviving in the ice did not depend on skin colour; the Lapps have survived, man survived the Ice Ages, by the master invention of all – fire.

  Fire is the symbol of the hearth, and from the time Homo sapiens began to leave the mark of his hand thirty thousand years ago, the hearth was the cave. For at least a million years man, in some recognisable form, lived as a forager and a hunter. We have almost no monuments of that immense period of prehistory, so much longer than any history that we record. Only at the end of that time, on the edge of the European ice-sheet, we find in caves like Altamira (and elsewhere in Spain and southern France) the record of what dominated the mind of man the hunter. There we see what made his world and preoccupied him. The cave paintings, which are about twenty thousand years old, fix for ever the universal base of his culture then, the hunter’s knowledge of the animal that he lived by and stalked.