Stable and Radiogenic Isotope Analysis of Faunal Remains from a Western Iowa Oneota Complex Site: An Investigation of Diet and Mobility Variation in the Late Prehistoric Period of the Upper Midwest

This study provides evidence of the value of using isotopic data from faunal remains to understand human diet and mobility patterns when human remains are not available for examination. In this research, bone apatite, bone collagen, and enamel apatite from fauna recovered from recent excavations of the Dixon site (13WD8), an Oneota complex site (AD 1300–1400) in western Iowa, were analyzed for δ13C, δ15N, δ18O, and 87Sr/86Sr values. The goals of this study were to gather information about human and animal diet and mobility and faunal procurement strategies of humans in the late prehistoric period of upper midwestern North America and to contribute to the growing literature using domesticated dogs as surrogates for humans in isotopic studies of dietary patterns. The results of this study find that the people occupying the Dixon site were subsisting on agricultural products, including maize, in conjunction with the gathered wild resources and hunted fauna, which included both large and small local game. While the Oneota complex is thought to be associated with some amount of seasonal migration, there is no evidence of these movements offered via this study's data nor is there strong evidence of long-distance hunting. Domesticated canids were an important part of the Dixon settlement and were fed human foodstuffs and scraps, including maize. At times, these canids were also a source of food. As a substitute for analyses of human remains, this study uses the canine surrogacy approach (CSA) and argues that the canid data would be similar to the human data from the Dixon settlement. A Bayesian stable-isotope mixing model (MixSiar) was used to quantitatively interpret the stable-isotope values of the Dixon canids, and it suggests that bison hunting was a specialization of the human population occupying the Dixon site.