DEER AS POTENTIAL CLIMATIC RECORDERS THROUGH TIME

Previous work has shown that stable isotope values from evaporation sensitive fossil mammals can be used to compare changing climatic conditions. Specifically, camelids (Palaeolama, Hemiauchenia, Camelops) were identified as evaporation sensitive taxa and were used to compare relative aridity at Pleistocene sites. The family goes extinct in North America during the terminal Pleistocene extinction event, making them ineffective for tracking North American climatic changes through paleoecological, historical (including archaeological), and modern ecological records. Deer (Odocoileus sp.) were also identified as evaporation sensitive taxon; therefore, Odocoileus virginianus was selected for isotope analysis as they are a spatially and temporally abundant taxon that persists in fossil, historical, and modern records. This work aims to clarify the stable isotope ecology of O. virginianus using tooth enamel to track climatic variables through stable carbon and oxygen isotope analysis. Two samples were taken from each molar (m) including m1, m2, and m3 to also investigate seasonal signals and influence of weaning through ontogeny. When bulk values for each tooth are compared, δ¹³C m1 values are significantly lower than m2 and m3 values (p<0.01) and δ¹⁸O m2 values are significantly lower than m1 and m3 values (p<0.05). Significantly lower δ¹³C values and higher δ¹⁸O values in m1s as compared to m2s likely reflect the contribution of lipid rich milk to the diet of deer, while weaning likely occurred after the formation of first molars. To determine if climatic interpretations could be made we compared δ¹⁸O values and seasonality of meteoric water to δ¹⁸O enamel values. Results demonstrate the potential utility of deer as climatic recorders, especially their ability to track seasonal variability in annual climates.