Citation: "The carbon isotope ecology and diet of Australopithecus africanus at Sterkfontein, South Africa" Nikolaas J. van der Merwe, J. Francis Thackerayc, Julia A. Lee-Thorp and Julie Luyt Journal of Human Evolution Volume 44, Issue 5 , May 2003, Pages 581-597 Abstract The stable carbon isotope ratio of fossil tooth enamel carbonate is determined by the photosynthetic systems of plants at the base of the animal's foodweb. In subtropical Africa, grasses and many sedges have C4 photosynthesis and transmit their characteristically enriched 13C/12C ratios (more positive delta-13C values) along the foodchain to consumers. We report here a carbon isotope study of ten specimens of Australopithecus africanus from Member 4, Sterkfontein (ca. 2.5 to 2.0 Ma), compared with other fossil mammals from the same deposit. This is the most extensive isotopic study of an early hominin species that has been achieved so far. The results show that this hominin was intensively engaged with the savanna foodweb and that the dietary variation between individuals was more pronounced than for any other early hominin or non-human primate species on record. Suggestions that more than one species have been incuded in this taxon are not supported by the isotopic evidence. We conclude that Australopithecus africanus was highly opportunistic and adaptable in its feeding habits. And a brief extract from the paper's discussion section: We can conclude that Australopithecus africanus at Sterkfontein had a well established C4 dietary component, which may well have included all of the available C4 food sources: grasses, particularly seeds and rhizomes; C4 sedges (which have starchy underground storage organs); invertebrates (including locusts and termites); grazing mammals; and perhaps even insectivores and carnivores. Whatever the sources were, different individuals of this early hominin species differed widely in their consumption of C4-based foods. Tom Billings