Mobility studies in fossil mammals from Laguna de las Cruces, San Luis Potosí, México: The strontium isotopic analyses

Abstract

Strontium isotopic ratios from dental enamel of fossil camels, Camelops hesternus (n=5), horses, Equus sp. (n = 5), and mammoths, Mammuthus columbi (4) from Laguna de las Cruces, San Luis Potosí, central Mexico, have been used to study their migration behavior. Four camels, all horses, and one mammoth display 87Sr/86Sr similar to local plants and soils, thus identified as residents. In contrast, teeth of one camel and two of mammoths show lower 87Sr/86Sr ratios while one mammoth has higher strontium isotopic ratios that indicate that they migrated from other localities. Oxygen isotopes from resident animals are similar, which suggests that those individuals drank water from the same source, whereas δ18O values of migrants are different, confirming the strontium isotopic data findings. However, as yet, it is not possible to determine where the migrants came from because their strontium ratios are different from the plants and soils 87Sr/86Sr values from other Potosian and Zacatecan localities with which they were compared.