Stable isotopic indicators of diet from two Late Prehistoric burial sites in Portugal: an investigation of dietary evidence of social differentiation

This paper details the results of a comparison of stable isotopic data from bone samples acquired from 31 individuals from two Late Neolithic-Copper Age (3500-2000 BC) burial sites in the Estremadura region of Portugal. The chosen sites of Feteira II and Paimogo I are geographically close and temporally overlapping but represent distinctive types of burial structures, one being a natural cave and the other a tholos. Because stable isotope analyses can quantify individual dietary intake, it can be useful in distinguishing patterns of food consumption within and between populations. The goal of this research was to ascertain if there are dietary differences that would indicate that socially-differentiated populations were interred in these burial spaces. The results of this study indicate diets based primarily on C3 plants and terrestrial animals for both sampled populations. Although several individuals do exhibit dietary signatures that suggest they were consuming some fish, marine resources do not appear to be major dietary staples in either group despite close proximity to the sea. Some variation in food and water consumption is apparent between individuals at the two burial sites with individuals at Feteira II exhibiting more variability in isotopic indicators of dietary carbohydrates and drinking water sources while individuals from Paimogo I exhibit more variability in protein source and intake. However, no statistically significance differences in isotopic values were found that would point to clear dietary distinctions between the compared burial populations.