548 ANNUAL REPORT SMITHSONIAN INSTITUTION, 196 2 



Little, if anything, is known about population size during this hunt- 

 ing and gathering stage of man's existence. The total land area of the 

 earth is approximately 58 million square miles. It seems reasonable to 

 assume that not more than 20 million square miles could have been used 

 successfully by the relatively few who inhabited the earth at that time. 

 The consensus of competent opinion indicates that, on moderately 

 fertile soil in a temperate climate, about 2 square miles per person 

 would be needed for a hunting and gathering economy. 



It must be assumed that there were severe limitations on man's 

 numbers during this period; and that his life cycle and average gen- 

 eration were much shorter than they are today. Man existed for the 

 most part in wandering bands in order to survive. Our ancient 

 ancestors were completely subject to all the vagaries of the weather 

 and the ecological cycle of the game animals on which their existence 

 depended. Food shortages were usually endemic, and the ravages of 

 epidemics were routine — although the wide dispersal of the popula- 

 tion tended to localize these hazards. Nevertheless, the picture that 

 emerges is one in which births and deaths were roughly balanced, with 

 births perhaps holding a narrow margin. 



THE LONG TIME-SPAN OF PREHISTORY 



Anthropologists and paleontologists are gradually putting together, 

 piece by piece, the great jigsaw puzzle that is the history of early man. 

 T. Dale Stewart, eminent physical anthropologist of the Smithsonian 

 Institute in Washington, D.C., points out that only a few fossils of 

 humans who lived in this period have been found. Nevertheless, 

 man's long time-scale is known today with far greater accuracy than 

 ever before, mainly because of the new radioactive dating techniques. 

 According to Dr. Stewart, new discoveries demand new theories or 

 the adjustment of existing theories. 



The remains of Zinjanthropus, recently found in the Olduvai gorge 

 of Tanganyika by L. S. B. Leakey, Curator of the Coryndon Museum, 

 Nairobi, Kenya, which Leakey believes date back almost 2 million 

 years, probably do not represent the beginning of the line. Zinjan- 

 thropus has been called man because he was a toolmaker, in the crudest 

 sense. Since his physical form represents a very early stage of human 

 evolution, it is not advisable to assume so early a beginning for pur- 

 poses of estimating human population growth. 



However, it is generally believed that "man" had reached the point 

 of being able to make simple tools and to talk by a half million or 

 even a million years ago. Homo sapiens first appeared witli great 

 force in Europe sometime between 25,000 and 30,000 years ago, though 

 he presumably emerged much earlier. Very little is known about 

 where he came from or about his connection with the Neanderthal 

 people who were one of many types of man to precede him. By 



