Sex Differences in Bilateral Asymmetry Among Hunter-Gatherers From the Lower Paraná River Wetlands (Argentina)

This study assesses sex differences in subsistence strategies through bilateral asymmetry in the upper and lower limbs of Late Holocene hunter-gatherers from the lower Paraná River wetlands (Argentina).

The sample comprises 55 adult individuals of both sexes. Entheseal changes, linear external measurements, and diaphyseal shape were analyzed to quantify absolute and directional asymmetries. Bivariate and bootstrap analyses were applied to identify sex differences, and Spearman correlations were used to explore relationships between asymmetries across skeletal elements. Comparative data from global hunter-gatherer populations were also considered to contextualize the findings.

Bilateral asymmetry ranged from 0% to nearly 30%, especially in upper limb midshafts. Males showed significantly greater asymmetry than females, particularly in the upper limbs. Right-side dominance was common in both sexes, though left-side dominance also appeared, especially in males. Positive correlations between asymmetries of different bones were more frequent in females, whereas males also displayed negative correlations.

High percentages of bilateral asymmetry are consistent with uni- and bimanual hunting techniques and food processing, possibly beginning in adolescence. Sex differences suggest a division of labor, with males likely performing high-intensity, unilateral tasks and rowing, while females engage in more balanced, bimanual activities. Comparisons with global hunter-gatherers reveal similar asymmetry patterns, though local deviations may reflect adaptations to specific environmental and economic contexts.