Biomechanical evidence for occupational specialization in Mesolithic-Neolithic hunter-gatherers from Zvejnieki, Latvia

Mesolithic cemeteries have greater dimensionality and scale that reflect emerging social complexity following the Upper Paleolithic. The Zvejnieki cemetery dates between the Middle Mesolithic and Late Neolithic, is associated with a persistent hunter-fisher-gatherer economy, and includes burials with pendants fashioned from mammal teeth. Stable isotopic analyses indicate dietary differences between individuals with pendants and without pendants beginning early in life. This context provides an opportunity to explore questions relating to occupational specialization using long bone cross-sectional geometry. Femoral cross-sectional properties from Zvejnieki were compared to a European database from the Upper Paleolithic to Neolithic to explore mobility. Femoral and humeral cross-sectional properties were compared between individuals with and without pendants to understand differences in mobility and manual activity in relation to mortuary practices. Diminished femoral rigidity and circular femoral shape were found at Zvejnieki, but no differences were observed between burial groups. Expanded cortical area and diminished medullary area were observed in the right humeri of males with pendants. Right humeral shape was comparatively circular among males with pendants, while right and left humeral shape was anteroposteriorally reinforced among males without pendants. Females with pendants had elevated right and left humeral shape ratios compared to females without pendants. Femoral morphology reflects reduced mobility, interaction with flat terrain, and exploitation of abundant, local resources at Zvejnieki. Differences in humeral cross-sectional properties between burial groups are consistent with specialized manual activity. These patterns reflect the economic and ideological components of independent specialization and point toward expanding social dimensions in Mesolithic-Neolithic hunter-gatherers.