LAUSR

Abstract In this paper, we report the stable carbon and nitrogen isotope analysis results of wild (n = 15) and domestic (n = 21) animal samples from the Proezzhaia I site, a fortified Medieval settlement in Trans-Baikal, Siberia. Additionally, we analyzed five modern freshwater fish samples from the Shilka River, which flows immediately north of the site. Together, these samples provide the first dietary stable isotope data for the entire Trans-Baikal region. Our results reveal a C3 plant dominated diet for all animal taxa sampled, but with a possible minor inclusion of C4 plant material in the diets of some cattle (Bos sp.) and horses (Equus sp.). We infer this C4 plant was likely a type of millet, the remains of which were identified at a contemporaneous site upriver. Additionally, these results indicate that some cattle and horses consumed plant material grown in 15N-enriched soil, which suggests several distinct animal management practices, or may indicate a trade in or movement of animals from an area with a different nitrogen isotope baseline.