Abstract

PIP: Demographic data from 3 different historical periods of the Mekranoti-Kayapo Indians of Central Brazil were used to examine various explanations for historical changes in fertility among this group. The possible effects of warfare on Mekranoti fertility were also examined since warfare has had an important role in many preindustrial societies. The Mekranoti are a group of 285 relatively unacculturated Indians living in a single village in southern Para, Brazil. As in precontact days, their economy is based on slash and burn agriculture, hunting, and fishing. To assess Mekranoti fertility, pregnancy histories collected from all women 15 years or older as of December 1976 were used. In precontact years a woman who survived to age 50 could expect to give birth 6.5 times. During the contact years this average dropped to 5.6 and in the postcontact period it soared to almost 8.5. The drop in Mekranoti fertility from precontact to contact years corresponds with an increase in mortality. The direction of these changes would support a "health" argument about fertility, but the degrees of change do not. Whereas mortality increased markedly after 1955, fertility fell only slightly. The data are not consistent with the view that changes in lactation periods are responsible for fertility changes. The number of uses of contraceptives per reproductive woman year did not not vary much in the different historical periods and certainly could not account for differences in Mekranoti fertility. The data suggest that fertility changes over Mekranoti history may be due in part to sexual abstinence resulting either from postpartum sexual taboos or, more importantly, from a lack of husbands. Sex imbalances resulting from high male mortality in warfare and subsequent disruption of marriages by disease and death left many women without spouses for long periods of time. The findings are consistent with other studies that found lower fertility associated with male absence. The Mekranoti are unusual in having monogamy together with high male mortality from warfare.