Origins of stable isotopic variations in Late Pleistocene horse enamel and bone from Alberta

Oxygen and carbon isotopic measurements of coevally formed bone and tooth enamel bioapatite from a modern equid show that these tissues record drinking water and diet isotopic signals in an identical fashion. Hence, data for both tissues can be combined to track movement, dietary changes, and seasonal variability over the animal’s lifetime, and climatic variability over longer time periods. This tool was tested for horses using ten paired tooth and bone samples to reconstruct conditions in Alberta during the Late Pleistocene. While post-mortem isotopic alteration confounded interpretation of the results, two key findings emerged: (i) pre- and post-Last Glacial Maximum (LGM) time periods based on radiocarbon dates correspond with high and low δ15N collagen values, respectively; and (ii) pre- and post-LGM horses have similar drinking water δ18O and diet δ13C values, suggesting that environmental conditions, including seasonality, were similar across the time periods represented by these samples