1Laboratory for Human Osteoarchaeology, Leiden University, 2Department of Anthropology, Northwestern University, 3Research Centre in Evolutionary Anthropology and Palaeoecology, Liverpool John Moores University
April 16, 2020 , Platinum Ballroom
Though skeletal sexual dimorphism is a helpful tool in archaeological and forensic contexts, evidence shows sexual dimorphism is expressed inconsistently among human populations. Cranial and pelvic nonmetric sex estimation methods have been reevaluated and recalibrated for specific ancestral groups/modern populations. Other studies show that climate can contribute to variation in sexual dimorphism as well, but little research has explored morphology shifts due to different climatic pressures.
This study aims to highlight variation across Köppen-Geiger climate classifications using a cross-population comparative study of standard nonmetric sex indicators of the cranium and pelvis. The three populations examined are a Native Alaskan sample (n=104), a component of the Terry Black collection (n=99), and a post-Medieval Dutch sample from Middenbeemster (n=118). These sex-balanced groups were compared for statistical significance of sexual dimorphism variation using one-way ANOVAs, Tukey-Kramer post-hoc tests, and Greene’s t-test. The nonmetric traits respond to climate with little consistency. However, there is a trend toward a reduction of sexual dimorphism in populations of colder climates for the supraorbital margin (p=0.09 and p=0.04), as well as a shift to a hyperfemale morphology in the mental eminence (p<0.05).
Despite confounding factors such as ancestral, occupational, and nutritional differences, variation among standard nonmetric traits used in sex estimation demonstrates that further exploration of the complex relationship between climate and sexual dimorphism is warranted. Future studies will improve forensic and archaeological procedures and produce more accurate skeletal assessments tailored to climatic influence.