Survivorship in gracile and robust Australopithecines: A demographic comparison and a proposed birth model



The age distributions for the two australopithecine types are examined and found to differ significantly as does the difference in average age at death: 22.9 years for Australopithecus africanus and 18.0 years for Australopithecus robustus. Survivorship curves for the two types are constructed. In addition, the survivorship curve for the australopithecine sample is compared to one group of pre-urban Homo sapiens and found to be much the same, if it is assumed the young australopithecines are not adequately represented. A proposed birth model is presented and it is concluded that both australopithecine types followed a human model of reproduction.