The last four chapters are a unit. They constitute the documentation for the racial history of man. The procession of skull after skull with accompanying teeth and long bones may seem a lengthy catalogue, but in reality it is not an overburdening mass of evidence. A total of a little over three hundred bone-bearing sites is not a large number: these sites encompass all our knowledge about the ancestry of a species that now numbers over two billions. All the pertinent information available in the literature on the subject and elsewhere had to be brought forth and considered. Only by examining every scrap of data could I hope to discover when and where each of the five lines of human descent began, and where each led.

But before I could start on this documentation, I had to establish some degree of credibility for my thesis, which I state in Chapter 1. My thesis is, in essence, that at the beginning of our record, over half a million years ago, man was a single species, Homo erectus, perhaps already divided into five geographic races or subspecies. Homo erectus then gradually evolved into Homo sapiens at different times, as each subspecies, living in its own territory, passed a critical threshold from a more brutal to a more sapient state, by one genetic process or another.

This point of view is not wholly original - I know, for instance, of two younger men who have thought it out independently of myself and of each other¹ - nor is it generally accepted. As I was working alone, with only Weidenreich's interpretation of the Sinanthropus material to guide me, I decided, before writing this book, to marshal many kinds of cognate evidence.

I studied genetic theory, zoogeography, and human physiology (with special reference to adaptations to climate and culture); the history of the primates, with its marvelous record of parallelism, by which such similar creatures as the Old and the New World monkeys could evolve from different prosimians; and the record of our hominid predecessors, the Australopithecines. I also made a survey of world archaeology covering the Pleistocene. In addition, I had to explain the differences among fossil men between evolutionary characteristics and those that are racial. These efforts filled eight chapters, numerically two thirds of the book, but without them, Chapters 9 through 12 would not have been solidly grounded.

Now that the task is over, I feel that the three Eurasiatic lines - the Australoid, Mongoloid, and Caucasoid - have been traced fully enough so that future discoveries will entail no major surprises. The African material, however, is less well documented, and new conclusions may be reached as new evidence becomes available.

As far as we know now, the Congoid line started on the same evolutionary level as the Eurasiatic ones in the Early Middle Pleistocene and then stood still for a half million years, after which Negroes and Pygmies appeared as if out of nowhere. The Ternefine-Tangier line has left us enough jaws and teeth to work with, only one very early but still unmeasured parietal from Ternefine, and two new pre-Mouillian skulls from Jebel Ighoud, Morocco. These skulls seem to support my hypothesis that the ancestors of the Bushmen and Hottentots originated north of the Sahara and only reached South Africa postglacially. After these skulls have been properly studied, they may also help explain why in the Middle Pleistocene North Africans resembled the earliest Mongoloids, whereas the East Africans were closest to the Caucasoids, and what role they may have played in the still enigmatic genesis of the Congoids.

We also urgently need new evidence concerning the details of the transition from the australopithecine to the human grade. The search for more early hominid fossils should be accelerated in the few suitable areas of the Old World which contain Lower Pleistocene deposits. Only when the key fossils have been found will we know where and when the major lines of human descent embarked on the separate paths that they have followed to this day.

Toward the end of the Pleistocene, after all five geographical races of man had become sapiens but before the two northernmost, the Mongoloid and Caucasoid, had completed their southward invasions and expansions, each race may have contained nearly equal numbers of individuals. However, by the time agriculture and animal husbandry had been invented, by Caucasoids and Mongoloids, these two had begun to outnumber the others. With the wide spread of food production, the numerical disproportion between the races increased; and today Mongoloids and Caucasoids together constitute the vast majority of the earth's inhabitants.

The Australoids are on the decline, except among the aboriginal tribes of India; and the Bushmen and Hottentots number only tens of thousands. The Pygmies are few, but hold their own. The African Negroes, on the other hand, have shown extraordinary vitality. They have been particularly versatile in adopting new cultures wherever they have been taken, as laborers, by Caucasoids and Mongoloids, and they have become the dominant racial element in many of the tropical lowland regions of the New World, as well as of Madagascar and parts of the Arabian coast. Once a race has become established as the principal population of a region, it has a tendency to stay there and to resist the genetic influences swept in by later invasions. Less than a thousand years ago the Arabs had a city near Amoy on the China coast, complete with minarets and bazaars. Thousands of Arab men must have impregnated Chinese women; yet today there is little if anything about the Fukienese to show it. Kashmiri traders live, marry local women, and die in the cities of Tibet, and Spaniards by the thousands have settled in the Andean altiplano, but today Tibetans and Andean Indians are as mongoloid as ever.
 

Shifts of Human Subspecies

from PLEISTOCENE to POST-PLEISTOCENE

Map 13

When two races come in to contact and mixture occurs, one race tends to dominate the other. The local advantage that the genetically superior group (superior for its time and place) possesses may be primarily cultural or primarily physiological, or a  combination of both. For example, the dominance of the Europeans over the native peoples of North America, Australia, and New Zealand is primarily cultural; that of the Negroes in the tropical lowlands of the New World and of the Indians in the Andes is primarily physiological.

There is, however, a third kind of dominance, expressed by the resistance of a population to the intrusion of large numbers of outsiders into its social and genetic structures. Call it xenophobia, prejudice, or whatever, people do not ordinarily welcome masses of strangers in their midst, particularly if the strangers come with women and children and settle down to stay. Social mechanisms arise automatically to isolate the newcomers as much as possible and to keep them genetically separate. This has happened historically to Jews (who wanted to preserve their culture) nearly everywhere, and to Negroes in the New World. It has happened recently to Europeans in India and Indonesia, and in Africa it is happening very dramatically to Europeans, even as I write.

The above is the behavioral aspect of race relations. The genetic aspect operates in a comparable way. Genes that form part of a cell nucleus possess an internal equilibrium as a group, just as do the members of social institutions. Genes in a population are in equilibrium if the population is living a healthy life as a corporate entity. Racial intermixture can upset the genetic as well as the social equilibrium of a group, and so, newly introduced genes tend to disappear or be reduced to a minimum percentage unless they possess a selective advantage over their local counterparts.

I am making these statements not for any political or social prupose but merely to show that, were it not for the mechanisms cited above, men would not be black, white, yellow, or brown. We would all be light khaki, for there has been enough gene flow over the clinal regions of the world during the last half million years to have homogenized us all had that been the evolutionary scheme of things, and had it not been advantageous to each of the geographical races for it to retain, for the most part, the adaptive elements in its genetic status quo.

This status quo entails not only the variations in bones and teeth that are evident in fossil man, and those of the surface features of living men, like skin, hair, lips, and ears, by which we can distinguish races almost at a glance, but also subtler differences seen only on the dissecting table or through the eyepieces of microscopes. Races differ in the extent and manner in which the fine subcutaneous muscles of the lips and cheeks have become differentiated from the parent mammalian muscle body; in the chemical composition of hair and of bodily secretions, including milk; in the ways in which different muscles are attached to bones; in the sizes and probable secretion rates of different endocrines; in certain details of the nervous system, as, for example, how far down in the lumbar vertebrae the neural canal extends; and in the capacity of individuals to tolerate crowding and stress. These and other details of racial difference I hope to describe and document in a later volume.

In studying racial differences in living men, physical anthropologists are now relying less and less on anthropometry and more and more on research in blood groups, hemoglobins, and other biochemical features. This is all to the good because the inheritance of these newly discovered characteristics can be accurately determined. In them, racial differences have been found, differences just as great as the better known and much more conspicuous anatomical variations. Being invisible to the naked eye, they are much less controversial than the latter in an increasingly race-conscious world. To me, at least, it is encouraging to know that biochemistry divides us into the same subspecies that we have long recognized on the basis of other criteria.

To readers who find these simple biological facts disconcerting, let me repeat something I said in Chapter 1. Until the present century, and in some countries until the present day, all five subspecies of man whose racial histories I have traced include populations of food gatherers and hunters living in the same regions that their ancestors occupied at least as early as early postglacial times. Some of the most backward in a cultural sense belong to the Mongoloid and Caucasoid subspecies, other populations of which have achieved the highest levels of civilization yet known in the world. But these backward populations do not live in their ancestral homelands; they hunt in distant regions that their ancestors invaded.

Caucasoids and Mongoloids who live in their homelands and in recently colonized regions, such as North America, did not rise to their present population levels and positions of cultural dominance by accident. They achieved all this because their ancestors occupied the most favorable of the earth's zoological regions, in which other kinds of animals also attained dominance during the Pleistocene. These regions had challenging climates and ample breeding grounds and were centrally located within continental land masses. There general adaptation was more important than special adaptation. Any other subspecies that had evolved in these regions would probably have been just as successful. Now the success of these groups is being challenged in many parts of the world as other groups who evolved later learn to use their inventions, especially modem means of communication. And evolution is still taking place, particularly natural selection resulting from crowding and stress, as described in Chapter 3.

In any case, neither the future of man nor the detailed description of the bodies, biochemical peculiarities, or behavior patterns of the living races of man is the subject of this book. I have, I hope, shown as accurately as the evidence warrants whence each of them came, and what steps guided it to its present position. Further details may be found in my new book, The Living Races of Man. (New York: Alfred A. Knopf; 1965).

Footnotes:

1 Frank Livingstone of the University of Michigan and Loring Brace of the University of California at Santa Barbara.