The Penguin History of the World

1 The Foundations

The roots of history lie in the pre-human past and it is hard (but important) to grasp just how long ago that was. If we think of a century on our calendar as a minute on some great clock recording the passage of time, then Europeans began to settle in the Americas only about five minutes ago. Slightly less than fifteen minutes before that, Christianity appeared. Rather more than an hour ago people settled in southern Mesopotamia who were soon to evolve the oldest civilization known to us. This is already well beyond the furthest margin of written record; according to our clock, people began writing down the past much less than an hour ago, too. Some six or seven hours further back on our scale, and much more remote, we can discern the first recognizable human beings of a modern physiological type already established in western Europe. Behind them, anything from a fortnight to three weeks earlier, appear the first traces of creatures with some human characteristics whose contribution to the evolution which followed is still in debate.

How much further back into a growing darkness we need go in order to understand the origins of man is debatable, but it is worth considering for a moment even larger tracts of time simply because so much happened in them which, even if we cannot say anything very precise about it, shaped what followed. This is because humanity was to carry forward into historical times certain possibilities and limitations, and they were settled long ago, in a past even more remote than the much shorter period of time – 4½ million years or so – in which creatures with at least some claim to human qualities are known to have existed. Though it is not our direct concern, we need to try to understand what was in the baggage of advantages and disadvantages with which human beings alone among the primates emerged after these huge tracts of time as change-makers. Virtually all the physical and much of the mental formation we still take for granted was by then determined, fixed in the sense that some possibilities were excluded and others were not. The crucial process is the evolution of human creatures as a distinct branch among the primates, for it is at this fork in the line, as it were, that we begin to look out for the station at which we get off for History. It is here that we can hope to find the first signs of that positive, conscious impact upon environment which marks the first stage of human achievement.

The bedrock of the story is the earth itself. Changes recorded in fossils of flora and fauna, in geographical forms and geological strata, narrate a drama of epic scale lasting hundreds of millions of years. During them the shape of the world changed out of recognition many times. Great rifts opened and closed in its surface, coasts rose and fell; at times huge areas were covered with a long-since vanished vegetation. Many species of plants and animals emerged and proliferated. Most died out. Yet these ‘dramatic’ events happened with almost unimaginable slowness. Some lasted millions of years; even the most rapid took centuries. The creatures who lived while they were going on could no more have perceived them than a twenty-first-century butterfly, in its three weeks or so of life, could sense the rhythm of the seasons. Yet slowly the earth was taking shape as a collection of habitats permitting different strains to survive. Meanwhile, biological evolution inched forwards with almost inconceivable slowness.

Climate was the first great pacemaker of change. About 65 million years ago – an early enough point at which to begin to grapple with our story – a long warm climatic phase began to draw to a close. It had favoured the great reptiles and during it Antarctica had separated from Australia. There were no ice-fields then in any part of the globe. As the world grew colder and the new climatic conditions restricted their habitat, the great reptiles did not manage to adapt, though it is likely that it was a sudden event – the impact of a giant asteroid – that killed them off completely. But the new conditions suited other animal strains which were already about, among them some mammals whose tiny ancestors had appeared 200 million years or so earlier. They now inherited the earth, or a considerable part of it. With many breaks in sequence and accidents of selection on the way, these strains were themselves to evolve into the mammals which occupy our own world – ourselves included.

Crudely summarized, the main lines of this evolution were probably determined for millions of years mainly by astronomical cycles and a few sudden events, such as eruption of massive volcanoes or the impact of asteroids. Climate was the all-important factor, changed by the earth’s position in relation to the sun or by short-term circumstances. A huge pattern emerges, of recurrent swings of temperature. The extremes which resulted, of climatic cooling on the one hand and aridity on the other, choked off some possible lines of development. Conversely, in other times, and in certain places, the onset of appropriately benign conditions allowed certain species to flourish and encouraged their spread into new habitats. The only major sub-division of this immensely long process which concerns us comes very recently (in prehistoric terms), slightly less than 4 million years ago. There then began a period of climatic changes which we believe to have been more rapid and violent than most observed in earlier times. ‘Rapid’, we must again remind ourselves, is a comparative term; these changes took tens of thousands of years. Such a pace of change, though, looks very different from the millions of years of much steadier conditions which lay in the past.

Scholars have long talked about ‘Ice Ages’, each lasting between 50,000 and 100,000 years, which covered big areas of the northern hemisphere (including much of Europe, and America as far south as modern New York) with great ice sheets, sometimes a mile or more thick. They have now distinguished some seventeen to nineteen (there is argument about the exact number) such ‘glaciations’ since the onset of the first, over 3 million years ago. We live in a warm period following the most recent of them, which came to an end some 10,000 years ago. Evidence of these glaciations and their effects is now available from all oceans and continents and they provide the backbone for prehistoric chronology. To the external scale which the Ice Ages provide we can relate such clues as we have to the evolution of humanity.

The Ice Ages make it easy to see how climate determined life and its evolution in prehistoric times, but to emphasize their dramatic direct effects is misleading. No doubt the slow onset of the ice was decisive and often disastrous for what lay in its path. Many of us still live in landscapes shaped by its scouring and gouging thousands of centuries ago. The huge inundations which followed the retreat of the ice as it melted must also have been locally catastrophic, destroying the habitats of creatures which had adapted to the challenge of arctic conditions. Yet they also created new opportunities. After each glaciation, new species spread into the areas uncovered by the thaw. Beyond regions directly affected, though, the effects of the glaciations may have been even more important for the global story of evolution. Changes in environment followed cooling and warming thousands of miles from the ice itself; and the outcome had its own determining force. Both aridification and the spread of grassland, for instance, changed the possibilities of species spreading themselves into new areas, especially if they could stand upright and move on two feet. Some of those species form part of the human evolutionary story, and all the most important stages in that evolution – so far observed – have been located in Africa, far from the ice-fields.

Climate can still be very important today, as contemplation of the disasters caused by drought show. But such effects, even when they affect millions of people, are not so fundamental as the slow transformation of the basic geography of the world and its supplies of food which climate wrought in prehistoric times. Until very recently climate determined where and how humans lived. It made technique very important (and still does): the possession in early times of a skill such as fishing or fire-making could make new environments available to branches of the human family fortunate enough to possess such skills, or able to discover and learn them. Different food-gathering possibilities in different habitats meant different chances of a varied diet and, eventually, of progressing from gathering to hunting, and then to growing. Long before the Ice Ages, though, and even before the appearance of the creatures from which humanity was to evolve, climate was setting the stage for and thus shaping, by selection, the eventual genetic inheritance of humanity itself.

One more backward glance is useful before plunging into the still shallow (though gradually deepening) pool of evidence. One hundred million or so years ago, primitive mammals were of two main sorts. Some, rodent-like, remained on the ground; others took or had taken to the trees. In this way the competition for resources was lessened and strains of each survived to people the world with the creatures we know today. In the second group were the prosimians. We are among their descendants, for they were the ancestors of the first primates.

It is best not to be too impressed by talk about ‘ancestors’ in any but the most general sense. Between the prosimians and ourselves lie millions of generations and many evolutionary blind alleys. It is important none the less that our remotest identifiable ancestors lived in trees because what survived in the next phase of evolution were genetic strains best suited to the special uncertainties and accidental challenges of the forest. That environment put a premium on the capacity to learn. Those survived whose genetic inheritance could respond and adapt to the surprising, sudden danger of deep shade, confused visual patterns and treacherous handholds. Strains prone to accident in such conditions were wiped out. Among those that prospered (genetically speaking) were some species with long digits which were to develop into fingers and, eventually, the oppositional thumb, and other forerunners of the apes already embarked upon an evolution towards three-dimensional vision and the diminution of the importance of the sense of smell.

The prosimians were little creatures. Tree-shrews still exist which give us some idea of what they were like; they were far from being monkeys, let alone men. Yet for millions of years they carried the traits which made humanity possible. During this time geography counted for much in their evolution, by imposing limits on contact between different strains, sometimes effectively isolating them, and thus increasing differentiation.

Changes would not happen quickly but it is likely that fragmentations of the environment caused by geographical disturbance led to the isolation of zones in which, little by little, the recognizable ancestors of many modern mammals appeared. Among them are the first monkeys and apes. They do not seem to go back more than 60 million years or so.

These monkeys and apes represent a great evolutionary stride. Both families had much greater manipulative dexterity than any predecessor. Within them, species distinct in size or acrobatic quality began to evolve. Physiological and psychological evolution blur in such matters. Like the development of better and stereoscopic vision, the growth of manipulative power seems to imply a growth of consciousness. Perhaps some of these creatures could distinguish different colours. The brains of the first primates were already much more complex than those of any of their predecessors; they were bigger, too. Somewhere the brain of one or more of these strains became complex enough and its physical powers sufficiently developed for the animal to cross the line at which the world as a mass of undifferentiated sensations becomes at least in part a world of objects. Whenever this happened it was a decisive step towards mastering the world by using it, instead of reacting automatically to it.

Some 25 or 30 million years ago, as desiccation began to reduce the area of the forests, competition for diminishing forest resources became fiercer. Environmental challenge and opportunity appeared where the trees and the grasslands met. Some primates, not powerful enough to hold on to their forest homes, were able, because of some genetic quality, to penetrate the savannahs in search of food and could meet the challenge and exploit the opportunities. Probably they had a posture and movement marginally more like that of men than, say, that of the gorillas or chimpanzees. An upright stance and the capacity to move easily on two feet make it possible to carry burdens, among them food. The dangerous open savannah could then be explored and its resources withdrawn from it to a safer home base. Most animals consume their food where they find it; man does not. Freedom to use the forelimbs for something other than locomotion or fighting also suggests other possibilities. We cannot confirm what the first ‘tool’ was, but primates other than man have been seen to pick up objects which come to hand and wave them as a deterrent, use them as weapons, or investigate and expose possible sources of food with their aid.

The next step in the argument is enormous, for it takes us to the first glimpse of a member of the biological family to which both man and the great apes belong. The evidence is fragmentary, but suggests that some 15 or 16 million years ago a very successful species was widespread throughout Africa, Europe and Asia. Probably it was a tree-dweller and certainly specimens were not very large – they may have weighed about forty pounds. Unfortunately, the evidence is such as to leave it isolated in time. We have no direct knowledge of its immediate forebears or descendants, but some kind of fork in the road of primate evolution seems to have occurred to its later relatives, often called hominids, around 5 million years ago. While one branch was to lead to the great apes and chimpanzees, the other led to human beings. This line has been named ‘hominin’. It is likely that the separation of these groups was a relatively slow process, occurring over millions of years, with episodes of interbreeding taking place. During that time big geological and geographical changes must have favoured and disfavoured many new evolutionary patterns.

The earliest surviving hominin fossils belong to a species which may or may not provide the ancestors for the small hominids which eventually emerged over a wide area of east and south-east Africa after this huge period of upheaval. They belong to the family now called Australopithecus. The earliest fragments of their fossils have been identified as over 4 million years old, but the oldest complete skull and a nearly complete skeleton found near Johannesburg in 1998 are probably at least half-a-million years ‘younger’ than that. This is not very different (allowing for the generous stretches of time and approximation available in prehistoric chronology) from the dating of ‘Lucy’, formerly the most complete specimen of Australopithecus discovered (in Ethiopia). Evidence of other species of ‘australopithecines’ (as they are usually termed), found as far apart as Kenya and the Transvaal, can be dated to various periods over the next 2 million years and has had a great impact upon archaeological thinking. Since 1970, something like 3 million years has been added to the period in which the search for human origins goes on, thanks to the australopithecine discoveries. Great uncertainty and much debate still surround them, but if the human species have a common ancestor it seems most likely that it belonged to a species of this genus. It is with Australopithecus, though, and with what, for want of a better word, we must call its ‘contemporaries’ that the difficulties of distinguishing between apes, man-like apes and other creatures with some human characteristics first appear in their full complexity. The questions raised are still becoming in some ways more difficult to deal with. No simple picture has yet emerged and discoveries are still being made.

We have most evidence about Australopithecus. But there came to live contemporaneously with some australopithecine species other, more man-like creatures, to whom the genus name Homo has been given. Homo was no doubt related to Australopithecus, but is first clearly identifiable as distinct about 2 million years ago on certain African sites; remains attributed to possible ancestors, however, have been dated by radioactivity to some 1½ million years before that.

Where specialists disagree and may be expected to go on arguing about such fragmentary evidence as we have (all that is left of 2 million or so years of hominid life could be put on a big dining-table), laymen had better not dogmatize. Yet it is clear enough that we can be fairly certain about the extent to which some characteristics later observable in humans already existed more than 2 million years ago. We know, for instance, that the australopithecines, though smaller than modern humans, had leg-bones and feet which were man-like rather than ape-like. We know they walked upright and could run and carry loads for long distances as apes could not. Their hands showed a flattening at the fingertips characteristic of those of men. These are stages far advanced on the road of human physique, even if the actual descent of our species is from some other branch of the hominid tree.

It is to early members of the genus Homo, none the less, that we owe our first relics of tools. Tool-using is not confined to men, but the making of tools has long been thought of as a human characteristic. It is a notable step in winning a livelihood from the environment. Tools found in Ethiopia are the oldest which we have (about 2½ million years old) and they consist of stones crudely fashioned by striking flakes off pebbles to give them an edge. The pebbles seem often to have been carried purposefully and perhaps selectively to the site where they were prepared. Conscious creation of implements had begun. Simple pebble choppers of the same type from later times turn up all over the Old World of prehistory; about 1 million years ago, for example, they were in use in the Jordan valley. In Africa, therefore, begins the flow of what was to prove the biggest single body of evidence about prehistoric man and his precursors and the one which has provided most information about their distribution and cultures. A site at the Olduvai Gorge in Tanzania has provided the traces of the first identified building, a windbreak of stones which has been dated 1.9 million years ago, as well as evidence that its inhabitants were meat-eaters, in the form of bones smashed to enable the marrow and brains to be got at and eaten raw.

Olduvai prompts a tempting speculation. The bringing of stones and meat to the site combines with other evidence to suggest that the children of early hominins could not easily cling to their mother for long foraging expeditions as do the offspring of other primates. It may be that this is the first trace of the human institution of the home base. Among primates, only humans have them: places where females and children normally stay while the males search for food to bring back to them. Such a base also implies the shady outlines of sexual differentiation in economic roles. It might even register the achievement of some degree of forethought and planning, in that food was not devoured to gratify the immediate appetite on the spot where it was taken, but reserved for family consumption elsewhere. Whether hunting, as opposed to scavenging from carcasses (now known to have been done by australopithecines), took place is another question, but the meat of large animals was consumed at a very early date at Olduvai.

Yet such exciting evidence only provides tiny and isolated islands of hard fact. It cannot be presumed that the East African sites were necessarily typical of those which sheltered and made possible the emergence of humanity; we know about them only because conditions there allowed the survival and subsequent discovery of early hominin remains. Nor, though the evidence may incline that way, can we be sure that any of these hominins is a direct ancestor of humanity; they may all be precursors. What can be said is that these creatures show remarkable evolutionary efficiency in the creative manner we associate with human beings, and suggest the uselessness of categories such as ape-men (or men-apes) – and that few scholars would now be prepared to say categorically that we are not directly descended from Homo habilis, the species first identified with tool-using.

It is also easy to believe that the invention of the home base made biological survival easier. It would have made possible brief periods of rest and recovery from the hazards posed by sickness and accident, thus sidestepping, however slightly, the process of evolution by physical selection. Together with their other advantages, it may help to explain how examples of the genus Homo were able to leave traces of themselves throughout most of the world outside the Americas and Australasia in the next million or so years. But we do not know for certain whether this was through the spread of one stock, or because similar creatures evolved in different places. It is generally held, though, that tool-making was carried to Asia and India (and perhaps to Europe) by migrants originally from East Africa. The establishment and survival in so many different places of these hominins must show a superior capacity to grapple with changing conditions, but in the end we do not know what was the behavioural secret which suddenly (to continue to talk in terms of prehistoric time) released that capacity and enabled them to spread over the landmass of Africa and Asia. No other mammal settled so widely and successfully before our own branch of the human family, which was eventually to occupy every continent except Antarctica, a unique biological achievement.

The next clear stage in human evolution is nothing less than a revolution in physique. After a divergence between hominins and more ape-like creatures, which occurred around 5 million years ago, it took rather less than 2 million years for one successful family of hominins to increase its brain size to about twice that of Australopithecus. One of the most important stages of this process, and some of the most crucial in the evolution of humanity, were already reached in a species called Homo erectus. It was already widespread and successful a million years ago, and had by then spread into Europe and Asia. The oldest specimen of the species so far found may be about half a million years older than that, while the last evidence for its survival (from Indonesia) suggests members of it were still living between 10,000 and 15,000 years ago, well after our own kind had spread throughout most of the earth. Homo erectus therefore successfully exploited a much bigger environment than earlier species and did so for much longer than has Homo sapiens, our species of modern man. Many signs once more point to an African origin and thence to a spread through Europe and Asia (where Homo erectus was first found). Apart from fossils, a special tool helps to plot the distribution of the new species by defining areas into which Homo erectus did not spread as well as those into which he did. This is the so-called ‘hand-axe’ of stone, whose main use seems to have been for skinning and cutting up large animals (its use as an axe in the usual, hafted sense seems unlikely, but the name is established). There can be no doubt of the success of Homo erectus as a genetic product.

Sub-species of Homo erectus survived for a very long time, and, although few scholars now believe that any of these, at least in their non-African form, is one of our direct ancestors, there is no precise dividing line between them and us (there never is in human prehistory, a fact it is only too easy to overlook or forget). With the different sub-species of Homo erectus we are already dealing with a creature who has added to the upright stance of his predecessors a brain approaching that of modern man in magnitude. Though we still know only a little of the way in which the brain is organized, there is, allowing for body size, a rough correlation between size and intelligence. It is reasonable, therefore, to attribute great importance to the selection of strains with bigger brains and to reckon this a huge advance in the story of the slow accumulation of human characteristics.

Bigger brains meant bigger skulls and other changes too. An increase in antenatal size requires changes in the female pelvis to permit the birth of offspring with larger heads, and another consequence was a longer period of growth after birth; physiological evolution in the female was not sufficient to provide antenatal accommodation to any point approaching physical maturity. Human children need maternal care long after birth. Prolonged infancy and immaturity in their turn imply prolonged dependency: it is a long time before such infants can gather their own food. It may be with the early Homo erectus that there began that long extension of tolerated immaturity, whose latest manifestation is the maintenance of young people by society during long periods of higher education.

Biological change also meant that care and nurture came gradually to count for more than large litters in ensuring the survival of the species. This in turn implied further and sharper differentiation in the roles of the sexes. Females were being pinned down much more by maternity at a time when food-gathering techniques seem to have become more elaborate and to demand arduous and prolonged co-operative action by males – perhaps because bigger creatures needed more and better food. Psychologically, too, the change may be significant. A new emphasis on the individual is one concomitant of prolonged infancy. Perhaps it was intensified by a social situation in which the importance of learning and memory was becoming more and more profound and skills more complex. About this point the mechanics of what is going forward begin to slip from our grasp (if, indeed, they were ever in it). We are somewhere near the area in which the genetic programming of the hominids is infringed by learning. This is the beginning of the great change from the natural physical endowment to tradition and culture – and eventually to conscious control – as evolutionary selectors, though we may never be able to say where precisely this change occurs.

Another important physiological change is the loss of oestrus by the female hominin. We do not know when this happened, but after it had been completed her sexual rhythm was importantly differentiated from that of other animals. Man is the only animal in which the mechanism of the oestrus (the restriction of the female’s sexual attractiveness and receptivity to the limited periods in which she is on heat) has entirely disappeared. It is easy to see the evolutionary connection between this and the prolongation of infancy: if female hominins had undergone the violent disruption of their ordinary routine which the oestrus imposes, their offspring would have been periodically exposed to a neglect which would have made their survival impossible. The selection of a genetic strain which dispensed with oestrus, therefore, was essential to the survival of the species; such a strain must have been available, though the process in which it emerged may have taken a million or a million and a half years because it cannot have been effected consciously.

Such a change has radical implications. The increasing attractiveness and receptivity of females to males make individual choice much more significant in mating. The selection of a partner is less shaped by the rhythm of nature; we are at the start of a very long and obscure road which leads to the idea of sexual love. Together with prolonged infant dependency, the new possibilities of individual selection point ahead also to the stable and enduring family unit of father, mother and offspring, an institution unique to mankind. Some have even speculated that incest taboos (which are in practice well-nigh universal, however much the precise identification of the prohibited relationships may vary) originate in the recognition of the dangers presented by socially immature but sexually adult young males for long periods in close association with females who are always potentially sexually receptive.

In such matters it is best to be cautious. The evidence can take us only a very little way. Moreover, it is drawn from a very long span of time, a huge period which would have given time for considerable physical, psychological and technological evolution. The earliest forms of Homo erectus may not have been much like the last, some of whom have been classified by some scientists as archaic forms of the next evolutionary stage of the hominin line. Yet all reflections support the general hypothesis that the changes in hominins observable while Homo erectus occupies the centre of our stage were especially important in defining the arcs within which humanity was to evolve. He had unprecedented capacity to manipulate his environment, feeble though his handhold on it may seem to us. Besides the hand-axes which make possible the observation of his cultural traditions, late forms of Homo erectus left behind the earliest surviving traces of constructed dwellings (huts, sometimes fifty feet long, built of branches, with stone-slab or skin floors), the earliest worked wood, the first wooden spear and the earliest container, a wooden bowl. Creation on such a scale hints strongly at a new level of mental ability, at a conception of the object formed before manufacture is begun, and perhaps an idea of process. Some have argued far more. In the repetition of simple forms, triangles, ellipses and ovals, in huge numbers of examples of stone tools, there has been discerned intense care to produce regular shapes which does not seem proportionate to any small gain in efficiency which may have been achieved. Can there be discerned in this the first tiny budding of the aesthetic sense?

The greatest of prehistoric technical and cultural advances was made when some of these creatures learnt how to manage fire. Until recently, the earliest available evidence of its use came from China, and probably from between 300,000 and 500,000 years ago. But very recent discoveries in the Transvaal have provided evidence, convincing to some scholars, that hominins there were using fire well before that. It remains fairly certain that Homo erectus never learnt how to make fire and that even his successors did not for a long time possess this skill. That he knew how to use it, on the other hand, is indisputable. The importance of this knowledge is attested by the folklore of many later peoples; in almost all of them a heroic figure or magical beast first seizes fire. A violation of the supernatural order is implied: in the Greek legend Prometheus steals the fire of the gods. This is suggestive, not solid, but perhaps the first fire was taken from outbreaks of natural gas or volcanic activity. Culturally, economically, socially and technologically, fire was a revolutionary instrument – if we again remember that a prehistoric ‘revolution’ took millennia. It brought the possibility of warmth and light and therefore of a double extension of the habitable environment, into the cold and into the dark. In physical terms, one obvious expression of this was the occupation of caves. Animals could now be driven out and kept out by fire (and perhaps the seed lies here of the use of fire to drive big game in hunting). Technology could move forward: spears could be hardened in fires and cooking became possible, indigestible substances such as seeds becoming sources of food and distasteful or bitter plants edible. This must have stimulated attention to the variety and availability of plant life; the science of botany was stirring without anyone knowing it.

Fire must have influenced mentality more directly, too. It was another factor strengthening the tendency to conscious inhibition and restraint, and therefore their evolutionary importance. The focus of the cooking fire as the source of light and warmth had also the deep psychological power which it still retains. Around the hearths after dark gathered a community almost certainly already aware of itself as a small and meaningful unit against a chaotic and unfriendly background. Language – of whose origins we as yet know nothing – would have been sharpened by a new kind of group intercourse. The group itself would be elaborated, too, in its structure. At some point, fire-bearers and fire specialists appeared, beings of awesome and mysterious importance, for on them depended life and death. They carried and guarded the great liberating tool, and the need to guard it must sometimes have made them masters. Yet the deepest tendency of this new power always ran towards the liberation of mankind. Fire began to break up the iron rigidity of night and day and even the discipline of the seasons. It thus carried further the breakdown of the great objective natural rhythms which bound our fireless ancestors. Behaviour could be less routine and automatic. There is even a discernible possibility of leisure.

Big-game hunting was the other great achievement of Homo erectus. Its origins must lie far back in the scavenging which turned vegetarian hominids into omnivores. Meat-eating provided concentrated protein. It released meat-eaters from the incessant nibbling of so many vegetarian creatures, and so permitted economies of effort. It is one of the first signs that the capacity for conscious restraint is at work when food is being carried home to be shared tomorrow rather than consumed on the spot today. At the beginning of the archaeological record, an elephant and perhaps a few giraffes and buffaloes were among the beasts whose scavenged meat was consumed at Olduvai, but for a long time the bones of smaller animals vastly preponderate in the rubbish. By about 300,000 years ago the picture is wholly altered.

This may be where we can find a clue to the way by which Australopithecus and his relatives were replaced by the bigger, more efficient Homo erectus. A new food supply permits larger consumption but also imposes new environments: game has to be followed if meat-eating becomes general. As the hominins become more or less parasitic upon other species there follows further exploration of territory and new settlements, too, as sites particularly favoured by the mammoth or woolly rhinoceros are identified. Knowledge of such facts has to be learnt and passed on; technique has to be transmitted and guarded, for the skills required to trap, kill and dismember the huge beasts of antiquity were enormous in relation to anything which preceded them. What is more, they were co-operative skills: only large numbers could carry out so complex an operation as the driving – perhaps by fire – of game to a killing-ground favourable because of bogs in which a weighty creature would flounder, or because of a precipice, well-placed vantage points, or secure platforms for the hunters. Few weapons were available to supplement natural traps and, once dead, the victims presented further problems. With only wood, stone and flint, they had to be cut up and removed to the home base. Once carried home, the new supplies of meat mark another step towards the provision of leisure as the consumer is released for a time from the drudgery of ceaselessly rummaging in his environment for small, but continuously available, quantities of nourishment.

It is very difficult not to feel that this is an epoch of crucial significance. Considered against a background of millions of years of evolution, the pace of change, though still unbelievably slow in terms of later societies, is quickening. These are not men as we know them, but they are beginning to be man-like creatures: the greatest of predators is beginning to stir in his cradle. Something like a true society, too, is dimly discernible, not merely in the complicated co-operative hunting enterprises, but in what this implies in passing on knowledge from generation to generation. Culture and tradition are slowly taking over from genetic mutation and natural selection as the primary sources of change among the hominins. It is the groups with the best ‘memories’ of effective techniques which will carry forward evolution. The importance of experience was very great, for knowledge of methods which were likely to succeed rested upon it, not (as increasingly in modern society) on experiment and analysis. This fact alone would have given new importance to the older and more experienced. They knew how things were done and what methods worked and they did so at a time when the home base and big-game hunting made their maintenance by the group easier. They would not have been very old, of course. Very few can have lived more than forty years.

Selection also favoured those groups whose members not only had good memories but the increasing power to reflect given by speech. We know very little about the prehistory of language. Modern types of language can only have appeared long after Homo erectus disappeared. Yet some sort of communication must have been used in big-game hunting, and all primates make meaningful signals. How early hominins communicated may never be known, but one plausible suggestion is that they began by breaking up calls akin to those of other animals into particular sounds capable of rearrangement. This would give the possibility of different messages and may be the remote tap-root of grammar. What is certain is that a great acceleration of evolution would follow the appearance of groups able to pool experience, to practise and refine skills, to elaborate ideas through language. Once more, we cannot separate one process from others: better vision, an increased physical capacity to deal with the world as a set of discrete objects, and the multiplication of artefacts by using tools were all going on simultaneously over the hundreds of thousands of years in which language was evolving. Together they contributed to a growing extension of mental capacity until one day conceptualization became possible and abstract thought appeared.

It remains true, though, that if nothing very general can be confidently said about the behaviour of hominins before man, still less can anything very precise be confirmed. We move in a fog, dimly apprehending for a moment creatures now more, now less, man-like and familiar. Their minds, we can be sure, are almost inconceivably unlike our own as instruments for the registration of the outside world. Yet when we look at the range of the attributes of Homo erectus it is his human, not pre-human, characteristics which are most striking. Physically, he has a brain of an order of magnitude comparable to our own. He makes tools (and does so within more than one technical tradition), builds shelters, takes over natural refuges by exploiting fire, and sallies out of them to hunt and gather his food. He does this in groups with a discipline which can sustain complicated operations; he therefore has some ability to exchange ideas by speech. The basic biological units of his hunting groups probably prefigure the nuclear human family, being founded on the institutions of the home base and a sexual differentiation of activity. There may even be some complexity of social organization in so far as fire-bearers and gatherers or old creatures whose memories made them the databanks of their ‘societies’ could be supported by the labour of others. There has to be some social organization to permit the sharing of co-operatively obtained food, too. There is nothing to be usefully added to an account such as this by pretending to say where exactly can be found a prehistorical point or dividing line at which such things had come to be, but subsequent human history is unimaginable without them. When an African relative of Homo erectus, perhaps possessing slightly larger and more complex brains than others, evolved into Homo sapiens it did so with an enormous achievement and heritage already secure in its grasp. Whether we choose to call it human or not hardly matters.