Fisherfolk and farmers: Carbon and nitrogen isotope evidence from Middle Horizon Ancón, Peru

This study investigates human dietary patterns and economic trends at the coastal site of Ancón, Peru during the Andean Middle Horizon (550 AD –1000 AD ) using stable isotopic data from 32 individuals buried at the site. δ 13 C and δ 15 N results from human bone collagen and δ 13 C from human tooth enamel and bone carbonate indicate that inhabitants consumed a mixed diet composed primarily of marine protein and C 4 resources, with only marginal reliance on C 3 foods. Over time, Ancóneros appear to have relied more heavily on C 4 resources, particularly maize, despite the fact that the crop could not have been grown locally. These results are notable given that C 3 rather than C 4 or marine foods dominate the site's archaeological record. These data suggest that Ancón's inhabitants either had access to more fertile land up‐valley where maize could be cultivated successfully or that they engaged in trade relationships with their valley neighbours. A third possibility is that increased maize consumption at Ancón during the Middle Horizon resulted from Wari imperial influence and interregional exchange. Comparisons of δ 13 C values in enamel and bone carbonate from Ancón individuals indicate that δ 13 C carb_enamel values are significantly more positive than δ 13 C carb_bone values. This suggests that the diets of young children were systematically enriched in 13 C compared to that of adults, perhaps as a result of nursing activity and/or differential dietary practices among various age groups at the site. Copyright © 2009 John Wiley & Sons, Ltd.