The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)

Regional Variation in Sexual Dimorphism among African and Diaspora Populations


Department of Anthropology, University of South Florida

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Studies concerning human sexual dimorphism can provide valuable information regarding the human condition and may help in understanding the influence of environmental, biological, cultural, and other factors that contribute to this variation. The purpose of this study is to evaluate and compare the regional variation of sexual dimorphism of 331 crania representing western (Benin, Chad, Congo, Ghana, Nigeria) and southern Africa (Botswana), as well as African Americans. An Index of Sexual Dimorphism (ISD) was calculated for each of the sixteen standard craniometric measurements, as well as the mean ISD for all variables. The mean ISD suggests that Botswana males and females (ISD = 5.76) are the most sexually dimorphic and the student’s t-test indicates that the degree of sexual dimorphism is significant between Botswana and all other groups (p-value < 0.05) except for Congo (p-value = 0.08). Comparisons of individual cranial variable ISDs suggest that the primary difference in the levels of sexual dimorphism is observed in the craniofacial variables. Additionally, Mahalanobis squared distances indicates significant differences between the three regional samples. Overall, the western African samples are not significantly different from one another, while the southern African sample and the African Americans are significantly different from all other groups (p-value < 0.05). The separation of both Botswana and the African Americans from the western African populations and the high degree of sexual dimorphism in Botswana suggests underlying biological variation within the cranium, which may have implications for human identification in human rights and forensic contexts.

This project was supported by Award No. NIJ 2008-DN-BX-K163 awarded by the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice. The opinions, findings, and conclusions or recommendations expressed in this presentation are those of the authors and do not necessarily reflect those of the Department of Justice.

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