Are Dogs Suitable Proxies for Humans in Archaeological Isotopic Dietary Assessments? Bayesian Analyses of Bone Collagen Stable Isotope Ratios from Ancestral Iroquoian Sites

Abstract Under the archaeological canine surrogacy approach (CSA) it is assumed that because dogs were reliant on humans for food, they had similar diets to the people with whom they lived. As a result, the stable isotopes of their tissues (bone collagen and apatite, tooth enamel and dentine collagen) will be close to the humans with whom they cohabited. Therefore, in the absence of human tissue, dog tissue isotopes can be used to reconstruct past human diets. Here d13C and d15N ratios on previously published dog and human bone collagen from fourteenth-seventeenth century AD ancestral Iroquoian village archaeological sites and ossuaries in southern Ontario are used with MixSIAR, a Bayesian dietary mixing model, to determine if dog stable isotope ratios are good proxies for human diets. The modeling results indicate that human and dogs had different diets. Human dietary protein came primarily from maize and high trophic level fish and dogs from maize, terrestrial animals, low trophic level fish, and human feces. This indicates that CSA is likely not a valid approach for the reconstruction of ancestral Iroquoian diets.