Integrating cortisol and isotopic analyses of archaeological hair: Elucidating juvenile ante-mortem stress and behaviour

Understanding childhood experiences of health and well-being is essential to reconstructing ancient life-ways. Here, archaeological hair samples from five juveniles from Cahuachi and near Huaca del Loro in the Nasca Region, Peru, are analyzed for their carbon- and nitrogen-isotope compositions and cortisol levels. Stable isotopic data are used to investigate dietary change and nitrogen metabolism, and cortisol levels are used to infer exposure to stress. Using a case study approach, we determined that juveniles have distinct, individualized experiences of diet and morbidity, which are, in some cases, similar to adult experiences in the same region. Overall, Nasca Region juveniles have high systemic cortisol levels (1444 ± 402 ng/g) compared to Peruvian adults (281 ± 35 ng/g; Webb et al., 2010). Younger juveniles have comparatively high δ15N values that decrease over several months, suggesting transition from breast milk to a weaning diet. Older juveniles exhibit patterns of dietary shifting similar to those determined for adults in the region, or suggestive of particular socioeconomic roles. This study demonstrates the value of applying biomolecular methods to juvenile mummified remains to better understand the life histories of children in archaeological contexts.