SEXUAL DIMORPHISM IN AUSTRALOPITHECUS-AFARENSIS

This study reassesses body weight sexual dimorphism inA. afarensis by applying equations that predict body weight from hindlimb joint size in a comparative sample of modern apes and humans. The resulting estimates show a level of body size dimorphism in this fossil hominid to be below that seen in modern gorillas or orang-utans, greater than modern species ofPan, and well above modernH. sapiens. This degree of dimorphism fits with the behavioral model proposed byFoley & Lee, 1989 in whichA. afarensis lived in large kin-related multimale groups with females that are not kin-related. The moderate level of body size sexual dimorphism found in this study removes one objection to the lumping of all Hadar hominids into a single species. © 1991 Academic Press Limited.