Cross-sectional analysis of long bones, occupational activities and long-distance trade of the Classic Maya from Xcambó--archaeological and osteological evidence.

Xcambó is a Classic period Maya site (250-700 AD) situated on the northern coast of Yucatan, Mexico. Archaeological evidence suggests that the site began as a salt production center but adopted a more administrative role as a commercial port in the Late Classic period. Economic growth, depending on its magnitude, could have affected the daily occupations of Xcambó's inhabitants. However, this is difficult to infer from the archaeological record. The aim of this study was to directly evaluate this possibility through skeletal analysis. Since diaphyseal robusticity and shape are predominantly influenced by mechanical loading history, long bone cross-sections can be used to access activity patterns. To this end, humeri and femora of 47 male and 35 female adult specimens from two Xcambó population samples were scrutinized. Our analysis satisfies general archaeological expectations and provides additional information on the population's physical response to economic growth. Decreasing robusticity and femoral anterior-posterior rigidity indicate an overall decrease in physical workload and mobility, concomitant with the site's increasing administrative function. We also observed a significant decrease in sexual dimorphism, possibly attributable to the differential response of male and female physical work spheres during socioeconomic change. In general, our findings suggest even nonsubsistence based socioeconomic change can significantly affect the bone structure of a population, rendering activity analysis an important aspect of the reconstruction of living conditions of past populations. Copyright 2008 Wiley-Liss, Inc.