In this book, we have followed our ancestors, both archaic and sapient, through some very remarkable episodes of migration. Migration has been a continuous activity throughout human prehistory, but it has also been cyclical in its intensity It has served as a distributor rather than a primary generator of human biological and cultural i nnovation, although there can be no doubt that any migration into a new and unfamiliar environment can alter the selective canvas within which mutation and innovation must operate. Often, we see generalized pulses or range expansions rather than actual population histories with specific details, especially in the Pleistocene, when the records are faint. During the Holocene, reconstructions can often become much sharper with the added perspective of comparative linguistics.
Successful prehistoric migrations would have required a number of important facilitating conditions. First comes opportunity through demographic profile; a successful migrant population must have been able to grow in numbers, although whether such growth came entirely from an increasing birth rate within or by assimilation of others from without can often be an interesting question. Obviously, growth was always from within in situations of initial colonization. Second comes opportunity through geographical access, usually reflecting environmental opportunity to enter a region that was previously inaccessible, whether previously occupied or not. Third comes opportunity through technology and economy. Early speakers of Indo-European languages would perhaps not have migrated anywhere if they were hunter-gatherers rather than Fertile Crescent farmers with a highly portable and land-hungry system of food production. Similarly, Polynesians would have gone nowhere without their boats.
To what degree was prehistoric migration a conscious process, as opposed to an unthinking reaction to some environmental imperative? In my view, the human migratory past becomes more coherent, and infinitely more interesting, if we allow our ancestors the ability to act rationally, to make decisions and choices, and to plan for the future. Human rationality can find ways around what might appear to be environmental or climatic imperatives, through the application of cultural knowledge. How far back in time we push these abilities is another matter, but they were probably present in some form two million years ago, lubricated by a rudimentary hominin language ability. We have no concrete information to the effect that we are more intelligent than our sapient ancestors at, let us say 40,000 years ago, although the differences will surely be compounded as we go back further in time.
First Migrants: Ancient Migration in Global Perspective, First Edition. Peter Bellwood. © Peter Bellwood. Published 2013 by John Wiley & Sons, Ltd.
In this book, therefore, I have promoted human agency rather than climatic or other environmental changes (for instance, in sea level) as the main stimulus behind any prehistoric migration. Postglacial climatic amelioration allowed food production and the migrations that resulted from it to develop, but it alone did not determine the Fertile Crescent and China as such crucial regions for early development. The crops, the animals, and their human exploiters also defined such situations, and while species distributions were climatically determined, it was not just postglacial warming that made wild wheat grow in Syria and wild rice in China. Prior long-term botanical histories also mattered.
However, I fully admit that looking for any single stimulus such as climate change or human free will to explain any situation in prehistory might be misguided. I like to think that human affairs then were just as complex in structure as human affairs today, and there are many situations in the world today that I would find very hard to understand or explain relying on just a single causal factor. Nevertheless, while simplification of complex situations can sometimes be unwarranted, simplification to some degree is necessary if one is to present a coherent account of human migration through the ages, across the whole world, without becoming buried under the minutiae, unable to see the light at the end of the tunnel.
In this book, I have tried to expose the foundations of the whole human array of biological and cultural variation, as it existed on the eve of the ancient world, the M edieval world, and the era of European colonization. I have maximized the significance of actual migrations of human populations as major creators of this array, depositing layer upon layer of human residue to build up the vast palimpsest that makes our species what it is today Many of these layers have been almost erased, like those laid down by the Anatolian and Yeniseian language groups, or by many once-meaningful parts of the archaeological record, or in the DNA of the Neanderthals. Minor hints of such former existences survive for those of us who are willing to search hard. I have also argued strongly against ideas that relate the observed biological and cultural patterning purely to factors which do not involve population migration, such as gene flow, cultural diffusion or language shift, since I regard such factors as being geographically localized in their direct impacts. I certainly do not deny the significance of such reticulate processes, but I believe that a world-wide and multidisciplinary perspective is necessary if we are to understand their significances correctly.
For instance, genetic and cultural factors that have high selective value, directly related to biological fecundity or cultural efficiency (e. g., a broad pelvis, strong heterosexual inclinations, the bow and arrow, the computer), can no doubt spread from one population to another through interbreeding or communication, rather than through migration alone. But whole genomes, whole languages and whole cultures have massive complexity, and, more importantly from a migration perspective, massive inertia. Some of their component variables are able to spread independently, but the whole entities not so easily unless the carriers of those entities choose to carry them physically via migration. The situation of cultural and genetic free-flow mixing across continents that seems to many people to characterize our world today is very much a result of cultural and especially religious freedom, technological wizardry and mass communication. I doubt that it characterized Paleolithic or Neolithic cultures that existed at tribal rather than state levels of organization, even if some of them did invest considerable energy in trade and exchange with distant regions.
Looking at all of the data on ancient migration presented in the previous chapters, can we make any further interesting observations? The most impressive migrations in human prehistory had nothing to do with ancient states or conquering armies, but were related entirely to small tribal populations of hunters and gatherers, farmers, and fisher folk. In general, the oldest migrations appear to have gone the furthest, especially those of the Palaeolithic hunter-gatherers who discovered the previously unsettled Americas and Australia. Once the continents, apart from Antarctica, had hunter-gatherer populations in residence, then subsequent migration by further hunter-gatherers into inhabited territory was more limited in extent. The First Americans were able to migrate much further than the Na-Dene or the Eskimo-Aleuts, simply because they got there first.
During the Holocene, rapid expansion commenced again with many of the early food producing populations, such as the Indo-Europeans, Bantu and Sino-Tibetans of the Old World. These populations, by virtue of their rapid demographic growth and developing technologies, were able to penetrate vast territories formerly the preserve of hunters and gatherers. However, once these early food producer migrations reached their pre-colonial limits, in both hemispheres, the pace of migration died down. In Eurasia, most significant continental-scale migration was long over by the time of Christ, only to commence again during the colonial era after ad 1500. Even the great post-Roman migrations of Germanic and Turkic speakers led to very little population or language change, except in those few cases in which Anglo-Saxons and Vikings were able to cross sea and found thriving new settlements.
We must therefore conclude that the Palaeolithic migrations were the greatest in geographical extent. The Holocene migrations of food producers were more limited in extent than those of the first Homo sapiens, or even the first Eurasian hominins, even if we lump the food producer migrations all together. This is partly because very extensive regions of the earth's surface were simply impossible for the establishment of successful agriculture, whereas virtually everywhere, apart from the most hostile deserts and mountains, and the poles, could support some form of hunting and gathering. Most of these food producer migrations also occurred into regions that were already settled, hence, they faced varying degrees of resistance, as likewise did those by hunter-gatherers in similar circumstances of pre-existing settlement. Some groups of course spread much further than others, with Austronesians perhaps taking line honors because of the intervention of so much sea, not to mention the fact that all of the Pacific Islands beyond the Solomons were previously empty. Migrations into empty or relatively empty territories spread more rapidly and successfully than migrations into densely inhabited terrain, a conclusion driven home by a simple examination of the course of European colonial history since ad 1500.1 Much always depended, of course, on the relative levels of population density and cultural complexity between indigenous and migrant groups.
Why did ancient populations commence their migrations? My instinct would be to place need for land and resources as the most common causal factor in situations of free and considered migration (not forced by war or other sources of desperation), both in the prehistoric past and in more recent history Issues connected with land and resources would presumably also have been uppermost in the minds of those actually migrating, rather than abstract worries about climate change or trends in demographic profile, neither likely to have been obvious to prehistoric people with only rudimentary methods of recording and notation.
Why did migrations cease? Those that entered empty territory continued apace until they met environmental barriers (mountains, deserts, sea). But not even climatic limits to farming stopped all farmers from spreading onwards into lives of obligatory hunting and gathering, as in the Great Basin of North America, the South Island of New Zealand, and probably the rainforests of the deep interior of Borneo. In previously occupied landscapes, we find so often that the greatest inertia, especially in food producer migrations, was caused by admixture and assimilation. We can see this clearly when we examine biological variation across many of the Old World major language families that were spread by relatively recent population migrations in Holocene time.
For instance, northern Europeans and South Asians, who speak unequivocally-related Indo-European languages, undoubtedly owe some of their differentiating physical features to natural selection that has occurred since the original Indo-European diaspora about 8500 years ago. Such are likely to include blue eyes and light skin color in the case of northern Europeans, and darker skin color and dark eyes in the case of South Asians. After all, these features are related directly to latitudinal variations in the intensity of solar radiation, especially ultraviolet light. But it is also clear from current genetic research that much of the differentiation relates directly to a carry-over of genetic substratum from the pre-Indo-European populations of each region (Chapter 7). These pre-Indo-European populations were perhaps even more differentiated from each other, after 40,000 years of natural selection amongst their Palaeolithic and Mesolithic ancestors, than are modern northern Europeans and South Asians. As I have stressed throughout this book, migration has never been an all or nothing aspect of human behavior, with extinction the only route for the indigenous. Migration into an inhabited territory will always have involved a process of admixture. This is surely true whether we are discussing deep prehistory, or the colonial era in Australasia and the Americas.
Questions also arise concerning the sizes of ancient migrations, in terms of human population numbers. Exact figures are impossible to obtain, although relative increases in population size and density can often be plotted from the archaeological and genetic records. We must also distinguish between actual groups of migrants at any one time, as part of a single event, and the overall aggregate sizes of whole ethnolinguistic migrations, such as those of the early Bantu or Indo-Europeans from start to finish (however concepts such as 'start' and 'finish' might be defined). The early Bantu and Indo-Europeans, of course, must eventually have numbered in the tens of thousands of people, spread over huge regions and through long periods of time, involving many uncoordinated but compounded individual episodes of small group migration.
If we focus on those individual episodes of migration, then we can be fairly sure that they were originally small in population numbers in prehistoric contexts. Mass coordinated migration, such as that which led to the recent European colonizations of Australia and North America, obviously could not have occurred in prehistory. There was simply not the transport technology nor the massive bureaucracy necessary to implement such a process. However, and I believe this to be very important, while initial groups of prehistoric migrants were necessarily small, their potential for demographic growth, once they reached new and encouraging circumstances, was in many cases absolutely phenomenal. We see this in so many cases, involving both hunter-gatherers and early farmers in prehistory, as well as in many comparative historical situations, some discussed in Chapters 1 and 2.
However, lest the reader thinks that migration was the only solution to a need for land and resources in prehistory, we must not forget that many populations who felt such needs never resorted to migration at all. The alternative to a migratory solution is to intensify production, assuming one has the technological ability to engage in such a course of action. Studies of late prehistoric and ethnographic cultures in New Guinea and Oceania reveal to us quite clearly that an increasing intensity of agricultural production reduces any incentive to migrate, simply because of the increasing value of improved land and the energy invested in creating it.2 In Chapter 8, I discussed an example of this involving early rice farmers on the fertile alluvial soils of the Yangzi Valley Early migrant food producers were more likely to have emanated from stressed hinterland environments than core environments of plenty, often perhaps as a result of domino effects originating through the various demographic or environmental imbalances that could arise within the latter regions. This is a generalization that fits well with farmer migration out of a rather heavily exploited late Neolithic Fertile Crescent, or from the hinterland of the Yangzi and Yellow rivers down the constricted and rather barren southern coastline of China into Fujian, Guangdong and Taiwan. It is no coincidence that Fujian and Guangdong were also the main source regions for the recent historical 'Chinese diaspora’, that carried so many settlers of Chinese origin into nineteenth - and twentieth-century Southeast Asia and Oceania.
Sometimes, perhaps, ancient migrants somehow beat the odds and found themselves in locations where no one could have dreamt they could go. I repeat from Chapter 9 the comment of George Catlin, concerning the Great Plains of North America in the 1830s, that groups of people could be “run off to a distant region, where they take up their residence and establish themselves as a nation.” I have tended in this book to treat migrations as rational processes that reflected specific demographic, cultural, and environmental circumstances, and that traveled in likely as opposed to unlikely directions. From the viewpoint of a scientific investigator, this is undoubtedly the assumption to make, since tracing something random and inchoate in human behavior back into prehistoric time is unlikely to be a rewarding exercise. However, I will happily admit that chance must have played just as much of a role as careful planning behind the outcomes of many prehistoric migrations.
What does the future hold for migration studies in human prehistory? I suspect that developments in human genetics, both autosomal and in ancient DNA, will have a tremendous impact. So too will advances in the use of computational techniques in comparative linguistics, and in fields such as chronology, residue analysis and stable isotope analysis in archaeology and bioanthropology But chance will always play a role in the recovery of data, given that so much has been destroyed and lost from the deep past. There will always be problems with small samples, unrepresentative samples, and sometimes misidentification. When I was writing First Farmers, for instance, major constructional activities in Arizona and southwestern Taiwan were bringing to light astounding remains of the activities of early farmers, revealing details of ancient life previously undreamt of. Recent excavations beneath the Bosporus in Istanbul are having a similar impact on our knowledge of many periods of the past there, including the Neolithic and the Byzantine port of Theodosius. Sadly, however, in many developing countries without strong laws to protect antiquities, similar constructional activities go unobserved by archaeologists, and archaeological records of any kind are almost nonexistent, or looted for greed and profit. The study of human prehistory should not be just a prerogative of wealthy nations, but should ideally involve the inhabitants of every country, given that the past belongs to everyone, equally We must all share our ancestral experiences without prejudice or superiority. As members of a single species, all humans alive now are just as modern, or just as ancient, as all other humans. There are no throw-backs or remnants. All that divides us is the ceaseless current of the past.
Notes
1. Boxer 1965; Crosby 1986.
2. For excellent statements to this effect see Brown and Podolefsky 1976 for the New Guinea Highlands; Kirch 1994 for the island of Futuna in western Polynesia.
World History
