A Reassessment of the Kung San
The !Kung San are a group of hunter-gathers that make their home in the northern Kalahari desert. Although many ecological and cultural changes have occurred within this group throughout the past thirty years, this article examines the gathering and subsistence patterns that characterize these people. Bentley examines the total fertility rate of the !Kung San and hypothesizes that the pattern of female energetics in their subsistence routine has a direct effect upon their fecundity (1984: 79). His perspective explores the topic of fertility in great depth, and represents a viewpoint that is absent from the text written by Richard Lee, The Dobe Ju’/hoansi. In fact, some of the hypotheses proposed by Bentley appear to contradict Lee’s own research, while others are supported by the findings of Lee.
One question that remains undecided regarding the low fertility rates of the !Kung is the degree to which this is a result of sociocultural means, or an effect of physiological and biological processes. Bentley examines the "intermediate variables" within Bongaarts’ reproductive equation, which is one means of illustrating and quantifying the mechanisms that may cause the low fertility rate, and demonstrates that this research seems insufficient in explaining fertility. Briefly, Bongaarts’ equation incorporates the following variables: total fertility rate, index of proportions married, index of contraception, index of induced abortion, index of lactational infecundability, and total fecundity (which includes fecundability, intra-uterine mortality, and permanent sterility).
In addition to showing that the intermediate variables of Bongaart’s equation are insufficient in explaining the below normal fecundity of the !Kung, Bentley also feels that arguments used to explain low fertility that depend on factors such as nutrition, health status, and lactational practices are also insufficient. The belief that infanticide was a primary controlling factor in fertility was invalidated: in 500 cases of live births, there were only six occurrences of infanticide (Bentley 1984: 95). Data regarding the "critical fat" hypothesis, the assertion that there is a minimum level of body fat required for the onset of menarche and maintenance of reproductive function, seems inconclusive in the evaluation of this theory (Bentley 1984: 98). According to Bentley, there is not any substantial evidence that indicates the cause of low fertility among the !Kung.
Bentley proposes that a correlation exist between energetics, endocrine function, and fecundity; physiological mechanisms are of great importance in understanding the population dynamics of mobile hunter-gatherer groups (1984: 104). He cites recent studies in sports medicine that seem to indicate that certain exercises lead to gonadal disorders such as late or delayed menarche, low gonadotropin levels, abnormal estrogen and progesterone levels, and a short...