Stable isotopic reconstruction of weaning and childhood diet during times of change: An examination of life history and health of San Francisco Bay Area juveniles

Abstract

This study explores the impact of environmental and social transitions on the weaning age, childhood diet, and health of 39 individuals who died in childhood from the prehistoric San Francisco Bay Area Ohlone site of CA-ALA-329 (Mánni Muwékma Kúksú Hóowok Yatiš Túnnešte-tka). The sample spans the Middle and Late Periods, during which these environmental and social transitions occurred. According to the stable carbon and nitrogen isotope composition of bone and dental tissues, weaning age does not differ between temporal periods. However, the age at which weaning starts does differ from Bay Area individuals who lived into adulthood reported in previous studies; individuals from the present study started to wean later. Isotopic signatures of childhood independent foraging were observed in five children (median age-at-death between 4 and 7.5 years). Three of these children lived during the Middle Period and two lived during the Late Period. In addition, there is a frequency of 59% of skeletal indicators of poor health within our sample, which implies that these individuals who died prematurely in childhood appear to have been stressed. These results suggest that life history and health are influenced by a variety of factors that contribute to stress, such as embodied capital, resource availability, plant intensification, and transition to a storage economy. This study contributes to anthropological discussions regarding the facultative nature of childhood and life history. Broadly speaking, this study addresses how past small-scale societies adapted to climate and social change and the consequences of these adaptations on society’s youngest and possibly most vulnerable members.