The diet at the onset of the Andean Civilization: New stable isotope data from Caral and Áspero, North-Central Coast of Peru

Objectives: The subsistence system of the first urban centers with monumental architecture from the North-Central Coast of Peru, the core area for the social complexity process of Central Andes, has been debated since the late 1960s. To shed light on this aspect, we report paleodietary data from the two most important sites of the Supe Valley: Caral (3000–200 BC), the major settlement of the middle valley, and Áspero (3000–1800 BC), a notable coastal settlement. Our main objective was to test the Maritime Foundations of Andean Civilization hypothesis. Materials and Methods: Stable isotope values (δ¹³C_col, δ¹³C_ap, and δ¹⁵N) from 52 individuals (70 samples: 44 bones and 26 teeth) were analyzed using conventional methods and Bayesian Mixing Models to address the role of marine products and plants in people's diet at both sites over time. Results: Our results suggest high C₃ carbohydrate consumption (55%–68% total calories in Áspero and >70% in Caral). The consumption of marine resources was stable for Áspero between 3300 and 1800 BC, but it decreased for Caral between 2550 and 200 BC. Discussion: Marine protein was more important in Áspero than in Caral over time. C₃ plants, possibly tubers, formed the foundation of the diet in both sites during the Formative period (~3000–200 BC). Maize was a marginal food (<12% of calories) at least until 800 BC (29% of calories). The Maritime Foundations hypothesis does not completely account for these findings. Our results suggest the predominance of crop-focused agriculture during the evaluated period.