These conflicts are extreme because so many cherished notions about our origins have been overturned by the Out of Africa theory. Our book will show why its basic tenets are correct, nevertheless, and will demonstrate that humankind’s common and recent ancestry has great importance, for it implies that all human beings must be very closely related to each other (as is also demonstrated by genetic studies). Human differences are mostly superficial, changes which took place in the blinking of an eye in terms of our whole evolutionary history. We may look dissimilar, but we should not be deceived by the stout build of the Eskimo, or the lanky physique of many Africans. What unites us is far more significant than what divides us. Our variable forms mask an essential truth–that under our skins, we are all Africans, the metaphorical sons and daughters of the man from Kibish.
African Exodus
The Origins of Modern Humanity
by Christopher Stringer and Robin McKie
(1996)
I have never been able to trace the source of my passion for fossils. Neither, to their eternal bafflement, could my family. Indeed, it was the basis for some unease that I spent so much of my childhood drawing and painting skulls–scarcely a healthy hobby for a growing boy, after all. I was also famed (if that is the right word) in our family for asking, as a youngster on one of my frequent visits to London’s Natural History Museum, if the attendants could give me any old bits of skeleton they didn’t need. Fortunately, their rebuff was of such gentleness that my ardor for ancient bones was left undented.
Indeed, such was my eagerness to spend my life among fossils that when I discovered it was possible to study human evolution as a special subject in its own right, I promptly discarded my dearly won place at medical school in order to devote myself to anthropology. The decision horrified my headmaster and my biology teacher, the latter concluding a sorrowful lecture with a prediction that I would never get a job “doing that subject.” My parents, to their eternal credit, suppressed their unease–and backed my decision.
I have since had many reasons to be grateful for their support. My mother and father helped me to pursue a career which has involved me in one of the great scientific dramas of modern times: the unfolding of a radical new understanding of our birth as a species and about the source of what are commonly called racial differences. This new theory has, in turn, triggered one of the fiercest, most bitter debates about our origins–a considerable achievement for a field already infamous for polemical divisions and open rivalry. As a result, I have been permitted to be both observer and participant in one of the great intellectual clashes of this century.
At the time of my introduction to the subject, however, I was merely concerned with trying to make a career in it. I graduated from University College London, still imbued with a love of the study of human evolution, and began to plan my Ph.D. research in 1969–in an intellectual climate dominated by a widespread antipathy towards social science, an aftermath of the student troubles of 1968. In addition, none of the “hard science” councils–which distributed cash for medical, scientific, or environmental projects–would take responsibility for research on fossil humans. The subject seemed to fall between all three. Despite the efforts of Michael Day (then at the Middlesex Hospital Medical School), Nigel Barnicot of University College London, and Don Brothwell of the Natural History Museum, I failed to raise the interests of any of these organizations.
By the summer of 1970, there were still no signs of a grant and my prospects of becoming a paleoanthropologist looked bleak. My biology teacher’s forebodings about my future occupation were beginning to look ominously prescient. Indeed, I was on the verge of giving up my temporary job at the Natural History Museum to go to a teachers’ training college when, at the last minute, a spare Medical Research Council post came up at Bristol University’s anatomy department: for a student to conduct research on human evolution. Jonathan Musgrave, a lecturer at the department, phoned Brothwell, who gave him my name. Within a month I was on my way to Bristol.
Jonathan Musgrave had studied Neanderthals, that mysterious, sturdy lineage of human precursors who had lived, died, and been buried in the caves of Europe tens of thousands of years ago, and whose relation to our own species, Homo sapiens, underpins our understanding of ourselves and our evolution. In Musgrave’s case, he had analyzed their hand bones, using a technique called multivariate analysis that exploits mathematical methods for examining many measurements at once. Two or more different objects–a pair of skulls, for example–are carefully surveyed, and a host of different measurements which mirror their shape are collected. Then, using the complex statistical methodology of multivariate analysis, it is possible to produce an overall measure of how much the two objects differ from each other. It is a powerful technique and I intended to use it on Neanderthal heads to determine just how similar they were to those of the Cro-Magnons, a race of early European members of Homo sapiens who thrived about 25,000 years ago and who were very similar to men and women today. As we shall see, this relationship is the source of considerable dispute among scientists today, for at its root lies the resolution of our own origins and nature. Did Neanderthals evolve into Cro-Magnons (and modern Europeans), or did the two represent distinct lineages or even species? I intended to bring an objective–not an emotional–approach to resolve these questions. I would use precise instruments such as calipers and protractors to determine skull height, breadth, and width; angle of forehead; projection of browridge; and dozens of other features to place Neanderthals and Cro-Magnons in their evolutionary context.
This work would shape my life and my career, it transpired–though I did not know this at the time. All that concerned me in the winter of 1970 was getting my hands on fossil skulls–many of which could be found in European museums where they had been gathering dust since the turn of the century. So Jonathan and I began to devise an itinerary that would allow me to visit the maximum number of the most important centers. In retrospect, planning and executing such a trip was only possible with the boldness–and naivete–of youth. (I was twenty-two years old at the time.) Musgrave had traveled around Europe by train to collect his data, but then he had been investigating hand bones, of which there are relatively few in the fossil record. Skulls are bigger, hardier, and tend not to slip through the paleontologist’s net so easily–which means there are far more bits of our predecessors’ heads scattered round museums than fragments of their fingers and thumbs. And that in turn meant that I needed to visit many more such learned institutions than Musgrave had. Unfortunately, I raised less than a thousand dollars in travel grants, and was forced to use my ancient Morris Minor car, and camp or stay in youth hostels.
So in July 1971, I left for Europe–having only set foot there twice before: on a brief school trip to Paris and to an Italian seaside resort with my parents. I spoke French passably, but otherwise had to rely on a series of phrase books. Letters were sent out to the museums, but a number, especially in France, East Germany, and Czechoslovakia, failed to send replies. I started in Belgium where I spent my first night in what seemed to be a hostel for vagrants, run by nuns! I studied the Spy skeletons (unearthed in 1886) which were among the first Neanderthal bones to be discovered, and which confirmed that these were the remains of a distinct kind of early human being (and not those of a single anatomical freak as had been suggested). In Germany, I was joined by my girlfriend, Rosie (now my wife), and she accompanied me for much of the rest of the expedition. I examined the original Neander Valley skeleton (after which these ancient people were named) in Bonn, and then omitting East Germany on the grounds that a visit there would surely end in tears, I moved on to Czechoslovakia, tense as this was the third anniversary of the Soviet-led invasion. There my car was emptied out all over the road, and I was interviewed for four hours by border officials who made it clear that they found a long-haired, Western anthropology student about as welcome as a hippie at a regimental reunion. “Your visit is of no value to the people of Czechoslovakia,” I was told in response to my pleadings that my work was of international scientific importance. I was a tourist, not a researcher, I was informed, and would therefore have to spend ten dollars a day in local currency, a sum that was utterly incompatible with my feeble budget. I cut my losses, and visit, and left Czechoslovakia after five days, although I still managed to find time to study both the Neanderthal and early Cro-Magnon remains kept at Brno.
After a brief stay in Vienna, we moved on to Zagreb, where I discovered that the head of its museum, Dr. Crnolatac, was out of the city and I was refused access to the largest collection of Neanderthals of all–the Krapina fossils excavated by the distinguished prehistorian Dragutin Gorjanovic-Kramberger. (His office had been perfectly preserved from that time, I discovered.) Many mysteries still surrounded this material, which had only been studied fully by one Western scientist, Loring Brace, of the University of Michigan, in the previous forty years. Perhaps I looked heartbroken, or possibly suicidal–for a junior curator took pity, and at great risk allowed me access to the Krapina fossils, which were regarded almost as holy relics by the Yugoslav scientific establishment.
I spent three days secluded with these fossil prizes. I was as happy as a fledgling paleontologist could be–until, on the second day, to my horror, one of the most important Krapina fossils, part of a face, came apart while I was measuring it. The prospect of a lifetime of Yugoslavian prison food flashed before my eyes until I realized the skull had separated along an old glued break. Rosie and I raced to a local hardware store, bought a tube of domestic adhesive, and amid much sweaty tension, I carefully reassembled one of the jewels of Yugoslavian science, watched by the junior curator, saving his neck, my career, and an international incident.
We drove south, with relief, to study another mystery fossil, excavated from the Petralona Cave in northern Greece and stored at Thessalonika University, before Rosie had to return home, leaving me to take a terrifying drive west across the Pindus Mountains to the ferry terminal at Igoumenitsa. In Italy, I studied the Neanderthal remains from Monte Circeo and Saccopastore, and had my car broken into in Rome, losing a number of important possessions, including a-human skull, a recent Homo sapiens specimen that I had brought along to act as reference material when making comparisons with ancient skulls–though God knows what my Italian thieves made of it. However, my precious measuring instruments and hard won data were not stolen. If I had lost these, I would–as I recorded in my diary–have simply thrown myself in the Tiber. From then on, I always slept with my data sheets under my pillow–only they were truly irreplaceable.
I finished my tour in France, the country that has the richest collections of human fossils in Europe. Unfortunately, my money had virtually run out, and following a second car break-in in Avignon, I was left with only the few dirty clothes in my laundry bag! I camped in the Bois de Boulogne in late October, with a decidedly limited wardrobe–not the most enjoyable experience of my life. To cap it all, one of the curators at the Musee de l’Homme proved to be less than helpful and I was denied access to the La Ferrassie skeleton, found in 1909 and the most complete of all Neanderthal fossils. Apparently studies of it had still not been completed sixty years after it had been discovered! I was also told that another key fossil skull, from the Jebel Irhoud cave in Morocco, had been returned there, an economy with the truth that was only revealed when secret assistance by another anthropologist–Yves Coppens, whose work on the East Side Story of human evolution will be discussed in Chapter 2–gave me furtive access to it.
At the end of October 1971, I returned home to Bristol after my four-month, 5,000-mile, fossil-measuring marathon. Rosie and I had had our tent swept away during a thunderstorm in Prague, the car exhaust had collapsed and had to be held together with a coat hanger, and I had lost fourteen pounds. On the other hand, I was positively fattened intellectually by the firsthand knowledge I had gained of Europe’s most important Neanderthal and Cro-Magnon skulls. The next two years were spent analyzing that data, and studying the Natural History Museum’s, and other, collections. I devoted much of my time to laboriously transcribing my measurements onto computer punch cards so they could be analyzed by Bristol University’s giant computer–a state-of-the-art machine that seemed impressive at the time, but which had less calculating power than a modern desktop machine. By the time I returned to the Natural History Museum at the end of 1973 as a senior research fellow, my Ph.D. was almost finished, and my conclusions were crystallizing.
I was sure–for a start–that Europe did not have two parallel, coexisting lines of human evolution, Neanderthal and modern, as some scientists had argued. Nor was it the case that Neanderthals represented a worldwide stage in the evolution of modern humans, as was also being suggested at the time. It looked like the Neanderthals had evolved in Europe, but that highly dissimilar Cro-Magnons had not. As I completed my Ph.D., I became convinced the Neanderthals were not our ancestors, that the early fossils of Europe recorded their evolution but not that of modern Homo sapiens, and that there was little sign of intermixture between Neanderthals and early modern people in either Europe or the Middle East, as some scientists had proposed. The latter had simply replaced the former. But where did those early modern people come from? I couldn’t say in 1974. There was simply too little evidence.
It was then that I became involved with the man from Kibish. Strongly built, stained in hues of blue and brown from his lengthy immersion in the soil, the fragments of his skull, jaw, and skeleton had been disinterred from their resting place on the banks of the River Kibish in Ethiopia in 1967. A year later, these anatomical relics were sent on a brief tour of research centers where they were copied and measured before being packed and sent back to Addis Ababa where they have remained ever since. I had first glimpsed these few, precious fragments of bone in Michael Day’s office while still a postgraduate student, and even included a mention of them in my Ph.D. However, it was not until 1974, when Michael Day was preparing to return them to Ethiopia, after measuring and copying them, and reconstructing their owner, that I got a proper look, an inspection that was eventually to trigger my fundamental rethink about the evolution of our species.
The man from Kibish (the skeleton’s features suggest he was a male) had a higher and rounder skull and a bigger chin than any Neanderthal, and his skeleton suggests his was a taller and lighter frame than we find in those archetypal cave people–though he still had a powerful physique compared with an average modern male, with a noticeable browridge over his eyes and a rather broad and receding forehead. His bones had been found by an expedition led by Richard Leakey, who is better known for his discoveries of far more ancient and primitive hominid fossils around Lake Turkana in northern Kenya, only a few hundred kilometers from the Kibish region of Ethiopia. Leakey’s own work at Kibish, one of his earliest adventures, was carried out on behalf of his father, Louis, who was leading the Kenyan contingent of a joint French-American-Kenyan dig in the Omo-Kibish area. Its aim was to investigate the sediments lying on either side of the lower reaches of the Omo River where it widens and flows south towards Lake Turkana in north Kenya.
As Richard recalls in his autobiography, One Life, he and his team only narrowly avoided being eaten by crocodiles at one stage of their expedition. This was difficult and uncomfortable work; yet, for all their pains, their reward was a meager hoard of human remains: a partial skull and skeleton, a second skull discovered on the opposite bank of the Kibish River, and a third small fragment of skull. No volcanic rocks, which often supply important geological and chronological data, were found around the site. However, samples of shells collected from well above the level of the Kibish dig were dated to around 40,000 years ago, indicating that the bones, which were found far below this sequence of beds, must be far older. In addition, shells from the same level as the Kibish site were dated using a special technique called uranium-series dating–which we shall meet later–to around 130,000 years old. As Leakey put it: “I have probably collected as many fossils as anyone else around, and the one thing I do know is where things come from. The best estimate we could get from the geology and dating … would place them [the Kibish fossils] at between 100,000 to 130,000 years old.”
At the time, by the standards of other African finds, this seemed an unremarkable date for a supposedly primitive human being. But, beginning with my thesis, I began to think more deeply about that man from Kibish. Surely his skull was too domed, the brow too small, the chin too strong, and the bones too fine for him to be classified as an ancient form of human being? Quite frankly, he basically looked like a modern human and–more than any Neanderthal–he appeared to be a far more likely ancestor for the relatively recent Cro-Magnon people of Europe. Nor was I alone. Michael Day, and a other few researchers whom we shall meet in Chapter 3, were also coming to a similar conclusion. So in 1976, at a Cambridge conference, I presented my ideas on the man from Kibish, and his importance as a prototype modern European. A paper on my lecture was eventually published two years later. However, apart from a few negative reactions such as a fairly dismissive critique of my methods and deductions by Milford Wolpoff, of the University of Michigan, whom we shall encounter later, my theorizing mostly fell on deaf ears.
Michael and I were undeterred, however, and in 1980, in response to an invitation to attend a conference at Nice, we decided to reexamine the Kibish 1 skull, and rigorously test how modern it was. It passed with flying colors. Michael also restudied the rest of the Kibish 1 skeleton and concluded it was equally modern-looking. Indeed, so modern and lithe were its proportions that we realized we might be dealing with a far more revolutionary piece of fossil evidence than we had previously realized. Could this be the oldest modern human of them all, we wondered? Was the Kibish Man a forerunner of all the men and women who populate our planet today? Michael and I presented a cautious assessment of the dating evidence at the conference in 1982 but insisted that the Kibish skeleton did indeed belong to an early modern human, and not a kind of African Neanderthal, as some scientists, such as Brace, had claimed. Our view was supported by Leakey: “Geological investigations and dating have shown that the two skulls [from Kibish] are about 130,000 years old, yet despite their antiquity they are both clearly identifiable as Homo sapiens, our own species. At the time of their discovery, scientists generally believed that our species had only emerged in the last 60,000 years and many considered the famous Neanderthal Man to be the immediate precursor to ourselves. The Omo fossils thus provided important evidence that this was not so.”
By now I was taking stronger and stronger lines on the distinctiveness of the different populations of early humans, and was edging towards the view that perhaps the Neanderthals were different enough from modern humans to not be grouped with us as Homo sapiens at all. (A couple of colleagues based in New York, Todd Olson and Ian Tattersall, and one in London, Peter Andrews, played a pivotal role in convincing me that my data clearly pointed that way. They gave me backbone when I needed it.) Instead, the Neanderthals seemed to represent a long-lived European line of evolution, but one which disappeared from the continent rapidly around 35,000 years ago. Neanderthal characteristics which had evolved and persisted for 200,000 years had been replaced by new ones in less than 10,000 years. I summarized my thinking in 1984 in Natural History magazine: “The origin of the Cro-Magnons’ modern characteristics seems to lie outside of Europe. Evidence from southwest Asia suggests that modern people replaced the Neanderthals about 40,000 years ago. Before then, it is necessary to look to Africa for the origin of the earliest modern humans.”
In other words, the Kibish Man was a far better candidate as the forebear, not just for the Cro-Magnons but for every one of us alive today, not just Europeans but all the other peoples of the world, from the Eskimos of Greenland to the Pygmies of Africa, and from Australian Aborigines to Native Americans. In short, the Kibish Man acted as pathfinder for a new genesis for the human species.
Since then, many paleontologists, anthropologists, and geneticists have come to agree that this ancient resident of the riverbanks of Ethiopia and all his Kibish kin–both far and near–could indeed be our ancestors, though it has also become clear that the evolutionary pathway of these fledgling modern humans was not an easy one. At one stage, according to genetic data, our species became as endangered as the mountain gorilla is today, its population reduced to only about 10,000 adults. Restricted to one region of Africa, but tempered in the flames of near extinction, this population went on to make a remarkable comeback. It then spread across Africa until, by about 100,000 years ago, it had colonized much of the continent’s savannas and woodlands. We see the imprint of this spread in biological studies that have revealed that races within Africa are genetically the most disparate on the planet, indicating that modern humans have existed there in larger numbers, for a longer time than anywhere else.
Then there has been the archeological evidence. For example, in the western branch of the African Rift Valley, on the eroded banks of the Semliki River, near the town of Katanda, archeologists led by the husband-and-wife team of John Yellen, of the National Science Foundation, Washington, and Alison Brooks, of George Washington University, have uncovered many treasures, including startlingly elegant bone harpoons and knives. Previously it was thought that the Cro-Magnons were the first humans to develop such delicate carving skills–50,000 years later. Yet this very much older group of Homo sapiens, living in the heartland of Africa, apparently displayed the same extraordinary skills. It was as if, said one observer, a prototype Pontiac car had been found in the attic of Leonardo da Vinci.
In addition, the team has found fish bones, including some from two-meter-long catfish. It seems the Katanda people were efficiently and repeatedly catching catfish during the spawning season, indicating that systematic fishing is quite an ancient human skill–and not some relatively recently acquired expertise, as many archeologists had previously thought. On top of this, archeologists have discovered evidence that one of the Katanda sites had at least two separate but similar clusters of stones and debris that look like the residue of two distinct neighboring groupings, signs of the possible impact of the nuclear family on society, a phenomenon that now defines the fabric of our lives.
All this evidence paints an intriguing picture about our recent African forebears and their sophisticated lifestyles. Bands of these people–armed with new proficiencies, like those honed by the men and women who had flourished on the banks of the Semliki–would have begun to thrive and multiply, eventually triggering an exodus from their homeland. Slowly they trickled northward, and into the Levant, the countries bordering the eastern Mediterranean. Then, by about 80,000 years ago, small groups were spreading across the globe via the Middle East, planting the seeds of human modernity in Asia and later on in Europe and Australia. In each region, these seeds slowly germinated until, about 40,000 years ago, something caused them to blossom with an explosive population growth.
It was one of the critical events in mankind’s convoluted route to evolutionary success. The nature of the trigger of this great social upheaval is still hotly debated, but remains a mystery at the heart of our “progress” as a species. Was it a biological, mental, or social event that sent our species rushing pell-mell toward world domination? Was it the advent of symbolic language, the appearance of the nuclear family as the basic element of human social structure, or a fundamental change in the workings of the brain? Whatever the nature of the change, it has a lot to answer for. It transformed us, after all, from minor bit players in a zoological soap opera into evolutionary superstars, with all the attendant dangers of vanity, hubris, and indifference to the fate of others that such an analogy carries with it.
Yet the nature of this new trait is not the only baffling question raised by the study of recent human evolution. Today men and women conduct themselves in highly complex ways: some are uncovering the strange, indeterminate nature of matter, with its building blocks of quarks and leptons; some are probing the first few seconds of the origins of the universe 15,000 million years ago; while others are trying to develop artificial brains capable of staggering feats of calculation. Yet the intellectual tools that allow us to investigate the deepest secrets of our world are the ones which were forged during our fight for survival, in a set of circumstances very different from those which prevail today. How on earth could an animal that struggled for survival like any other creature, whose time was absorbed in a constant search for meat, plants, and raw materials, and who had to maintain constant vigilance against predators, develop the mental hardwiring needed by a nuclear physicist or astronomer? This is a vexing issue that takes us to the very heart of our African Exodus, to the journey that brought us from precarious survival on a single continent to global control.
If we can ever hope to understand the special attributes that delineate a modern human being we have to attempt to solve such puzzles. How was the Kibish Man different from his Neanderthal cousins in Europe, and what evolutionary pressures led the Katanda people to make such crucial changes in behavior–in the heart of a continent that has for far too long been stigmatized as backward? These are intriguing questions–though I would never have dreamed my early fossil forays would lead to the posing of such fundamental inquiries.
This book–the work of a scientist, myself; and a journalist, Robin McKie–aims to provide some answers to questions like these, and to help us understand what it means to be human. We shall do this using three main sources of evidence: paleontological (bones), archeological (stones), and DNA (genes)–with a dash of human observation thrown in for good measure. In the next chapter, we shall follow the story of the emergence of the human lineage, a range of creatures who began their separate existence as “apes who left the trees” and who began to walk upright. In the succeeding chapter, we shall explore how studies of our mysterious predecessors, the Neanderthals, have played a powerful role in shaping our ideas about our own evolution, research that led many scientists to conclude that these people were the ancestors of modern Europeans. We shall also focus on the subsequent studies that have led to the overthrow of this notion, an act that has helped trigger a revolution in our self-awareness as a species. In Chapter 4, we will investigate why Homo sapiens triumphed at the expense of the Neanderthals. These chapters will reveal how recent are mankind’s African origins, a feature highlighted in Chapter 5, which will survey the genetic evidence that underpins this idea and which also shows how startlingly similar is every member of the human population of this planet. Chapter 6 will trace mankind’s footsteps as our ancestors embarked on their African Exodus, crossing the world, leaving enigmatic traces of their presence. In Chapter 7, we will investigate the aftermath of that conquest–the establishment of the world’s different contemporary populations. These are the various races into which humanity is divided, a classification whose significance has been utterly transformed by our awareness of our recent African origins. Then in the penultimate chapter, we will probe one of the most important questions: Was one piece of mental architecture responsible for our rapid rise to world dominion? And finally, we shall look at the legacy of that ascendancy, the Stone Age bodies and the impulses of modern humans, features that confirm the strange story of our evolution and which ultimately threaten to eclipse us as a species.
Of course, our reconstruction of mankind’s history is not the only one that can be created from the scientific data available, but for us it is the most realistic one. As Jacob Bronowski said: “Science is a very human form of knowledge. We are always at the brink of the known, we always feel forward for what is to be hoped. Every judgement in science stands on the edge of error, and is personal. Science is a tribute to what we can know, although we are fallible.” Some will therefore disagree with us, and a few may become quite apoplectic, for this is an intensely disputed intellectual area, a scientific battlefield that has witnessed clashes of such vehemence that they make the row set off by the Piltdown Man fraud look like an amiable ecclesiastic debate.
These conflicts are extreme because so many cherished notions about our origins have been overturned by the Out of Africa theory. Our book will show why its basic tenets are correct, nevertheless, and will demonstrate that humankind’s common and recent ancestry has great importance, for it implies that all human beings must be very closely related to each other (as is also demonstrated by genetic studies). Human differences are mostly superficial, changes which took place in the blinking of an eye in terms of our whole evolutionary history. We may look dissimilar, but we should not be deceived by the stout build of the Eskimo, or the lanky physique of many Africans. What unites us is far more significant than what divides us. Our variable forms mask an essential truth–that under our skins, we are all Africans, the metaphorical sons and daughters of the man from Kibish.