Dietary changes in Plio-Pleistocene hominins from Sterkfontein, South Africa, based on stable carbon and nitrogen isotope ratios

Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios are used for the reconstruction of past diet and environments. δ¹³C of herbivores can differentiate between browsers and grazers as well as indicate prey preference of carnivores. δ¹⁵N shows trophic level: carnivores are 3 – 6 ‰ enriched compared to herbivores. δ¹³C is measured on the inorganic portion of tooth enamel, as enamel is highly robust to alteration. δ¹⁵N is measured on the organic fraction of collagen, which only rarely preserves past 50 ka. In 2021, a method was established at the MPIC that allows for the measurement of the small fraction of organic nitrogen within the mineral structure of enamel. Sterkfontein is a cave site in the Cradle of Humankind, South Africa, where all three hominin genera have been found. My project focusses on three infills of the cave. The Jacovec Cavern (3.6 Ma) has yielded Australopithecus fossils. Member 5 Oldowan (2.1 – 1.7 Ma) contained Paranthropus fossils, and Member 5 Acheulean (1.7 – 1.4 Ma) yielded early Homo specimens. I sampled tooth enamel of herbivores, carnivores, and hominins from each infill and measured δ¹³C and δ¹⁵N to reconstruct dietary behavior and the potential onset of meat consumption.