150 BUREAU OF AMERICAN ETHNOLOGY [Bull. 197 



the extreme variations in mortality which were characteristic of 

 most North American Indian tribes during the period of initial contact 

 with European settlers (Wissler, 1936 a, 1936 b; Aberle et ah, 1940; 

 Clements, 1931; Krogman, 1935). 



In his study of early Navaho history, Worcester (MS.) mentions 

 four factors which are associated with the relative stability of Navaho 

 death rates throughout this period. First, their food supplies were 

 sufficiently stable to permit survival, albeit with much periodic hard- 

 ship. Secondly, the early cessation of hostilities against the Ameri- 

 cans and the effective prohibition of predatory activities both by 

 and against Navahos after 1864 combined to eliminate the heavy 

 male mortality which commonly occurred among Plains Indian 

 tribes. Thirdly, the geographic dispersion of the Navaho effectively 

 insulated them from the worst effects of epidemics which decimated the 

 populations of many densely settled Indian villages and communities. 

 Finally, the profomid isolation of most Navahos from outside con- 

 tacts permitted them to maintain a relatively stable social existence 

 from the time of their return to their homelands in 1869 well into the 

 20th century. 



The numbers of births and deaths that were reported as occurring 

 among the population of the Navaho during selected years from 1884, 

 when the first such report was made, to 1957, are shown in table 29. 

 The 1884 report includes the earliest estimate of the Navaho fertility 

 and mortality I found, except for scattered references regarding 

 the mortality of the Navaho during the Fort Sumner period. As is 

 noted in the footnotes to table 29, the data shown for the years from 

 1912 through 1928 were selected in order to illustrate the nature of the 

 vital statistics that are available for this period. The reader should 

 note, further, that Navaho vital statistics during this period are fre- 

 quently combined with those of the Hopi or the small number of 

 Paiutes residing under the jurisdiction of the Western Navajo Agency 

 at this time. 



Even a cursory examination of the crude rates of birth, death, and 

 natural increase that are derived from these data suffices to indicate 

 their extreme mireliability. The crude birth rates vary from lows of 

 under 10 per 1,000 to highs of 120 per 1,000. The crude death rates 

 display similar variation, from lows around 7 per 1,000 to highs of 120 

 and 178 per 1,000. Although death rates might be expected to vary 

 more sharply than birth rates, due to the impact of sporadic epidemics, 

 there is no historical evidence to support these amazing variations in 

 mortality (except for the general rise in mortality that accompanied 

 the influenza pandemic of 1918-19). The crude rates of natural in- 

 crease that are derived from these data display similar implausible 

 variation, from a net decrease of 12 percent per year to a net increase 

 of 4.3 percent per year. It should be noted in this regard that where 



