BODY DIMENSIONS AND DIFFERENTIAL FERTILITY IN KUNG SAN MALES FROM NAMIBIA

The relationship between paternal somatic morphology and number and se x of the offspring was investigated with 114 !Kung San males from Nami bia. Significant correlations were observed between measures of facial and distal robustness and the total number of sons and daughters as w ell as for the sex ratio of children and the ratio of living to dead c hildren. Anthropometric characteristics of !Kung San men correlated wi th the number of daughters more frequently than with the number of son s, and the majority of correlation coefficients were negative. This in dicates that more slender men tend to have more daughters, while the p ositive correlations between body dimensions and the number of sons de monstrate that more robustly built and tall men tend to have more sons . Mortality of children also differs relative to the paternal body bui ld. The mortality rate in children of more slender fathers is higher t han in those of more robust fathers. Robust men have more male childre n and these children have a better chance to survive. The differential fertility of the !Kung may be explained by the association between a high social rank and robustness of physique which may lead to typical patterns of sexual selection. The results of the present study are con sistent with the Trivers-Willard hypothesis, which describes different ial sex-biased parental investment under different socioeconomic condi tions. (C) 1994 Wiley-Liss, Inc.