Does upper limb robusticity and bilateral asymmetry support subsistence intensification at Roonka, South Australia?

Abstract

During the Holocene, what is now the state of South Australia experienced a shift to a drier climate with more frequent droughts c. 4 ka. The ‘intensification model’ in Australian archaeology proposes that Aboriginal people adopted subsistence strategies that exploited resources with high processing costs, while the ‘risk minimization’ model posits that people adopted more flexible foraging strategies. The purpose of this study is to determine whether human groups in South Australia demonstrate evidence for intensification or risk minimisation in response to declining patch quality by examining bone properties of the upper limb in a Holocene skeletal sample from Roonka. Cross-sectional geometry of the humeri and radii was used to examine temporal trends of diaphyseal rigidity and bilateral asymmetry in both sexes. Women show a significant temporal increase in robusticity and rigidity of the upper limbs; men have similar measurements between time periods. Neither sex exhibits a difference in bilateral asymmetry of the humeri and radii over time. These results support risk minimisation at Roonka. In the late Holocene, it is possible that men hunted large game, while women had mixed foraging strategies that involved hunting small game, digging tubers, processing seeds, and collecting shellfish to mitigate high resource variance.