Human and animal subsistence in northern Iberia during the Late Chalcolithic-Bronze Age : biomolecular insights from Muela de Borja, Ebro Valley

This study explores human diet and animal management strategies in multiple Late Chalcolithic and Bronze Age (2550–1200 cal BCE) sites (Moncín, Majaladares, El Estrechuelo and El Balcón) located in Muela de Borja in the Ebro Valley, Northern Iberia, through the application of stable carbon (δ13C) and nitrogen (δ15N) isotope analysis and zooarchaeology by mass spectrometry (ZooMS). Thirty-three animal and nine human bones were analysed across the four sites. ZooMS enabled us to identify a number of fragmented animal bones whose species representation reflected that of the wider zooarchaeological assemblage. The isotopic results complemented by a Bayesian stable isotope mixing model (BSIMM) indicate that all humans had a relatively uniform diet consisting of C3 terrestrial plant and animal resources, despite representing a range of burial sites and a broad chronology. In contrast, animals had a highly variable diet, which suggests the existence of diverse feeding and management strategies within and between species. When comparing data from these sites to other published sites of a similar chronology, we see regional patterns in δ13C and δ15N that reflect environmental differentiation. These results provide a deeper understanding of the diversity of human and animal dietary practices during the Late Chalcolithic and Bronze Age in the Ebro Valley and Northern Iberia.