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Population variation in second metacarpal sexual size dimorphism
1Anthropology Program, University of Northern British Columbia, Prince George, British Columbia V2N 4Z9, Canada. lazenby@unbc.edu
American Journal of Physical Anthropology
|July 19, 2002
Summary
Sexual size dimorphism in the second metacarpal bone was higher in 19th-century Euro-Canadian settlers than in central Canadian Inuit. This finding challenges the idea that technological advancement always reduces such differences.
Area of Science:
- Biological anthropology
- Paleopathology
- Human osteology
Background:
- Sexual size dimorphism (SSD) is a common trait in many species, influenced by genetic and environmental factors.
- Understanding SSD variation across different populations provides insights into evolutionary and biocultural influences.
Purpose of the Study:
- To compare sexual size dimorphism in osteometric and geometric morphology of the second metacarpal bone.
- To investigate biocultural factors influencing SSD in 19th-century Euro-Canadian settlers and proto/historic central Canadian Inuit.
Main Methods:
- Analysis of second metacarpal osteometric and geometric morphology.
- Statistical comparison of dimorphism levels between Euro-Canadian and Inuit populations.
Main Results:
- Significant within-group sexual size dimorphism was observed in all measured variables for both populations.
- Euro-Canadian settlers exhibited higher levels of sexual size dimorphism compared to Inuit across all variables.
- Differences were particularly noted in geometric measures sensitive to functional strain, suggesting activity profile variations.
Conclusions:
- Proximate factors, such as distinct activity profiles and potentially nutritional stress, may explain observed differences in sexual size dimorphism.
- Traditional models involving marriage practices or subsistence-based labor division do not adequately explain the observed dimorphism patterns.
- Higher dimorphism in the 19th-century settler sample contradicts the assumption that technological progress invariably reduces sexual size dimorphism.