Nature Ecology & Evolution nature ecology & evolution https://doi.org/10.1038/s41559-025-02798-1 Article Geochemical chronologies in Paranthropus robustus teeth inform habitat and life histories Andrew Sillen  1 , Christopher Dean  2,3 & Vincent Balter  4 Radiogenic strontium isotopes ( 87 Sr/ 86 Sr) and the alkaline earth ratios (AERs) Sr/Ca and Ba/Ca in fossil dental enamel can inform the habitat, residence and life histories of early hominins recovered from the Pleistocene cradle-of-humankind sites of Gauteng, South Africa. Key questions, which may be addressed with these indices, are the relative exploitation of wet versus dry botanic regimes and whether early hominins dispersed in a manner similar to that of chimpanzees (characterized by male philopatry and female dispersal at puberty) or to that of humans (who are not so characterized). Here we developed 28 new dental chronologies in 20 Paranthropus robustus teeth from Swartkrans and Kromdraai. Resulting geochemical time series demonstrate that, while maternal 87 Sr/ 86 Sr in earlier-forming teeth varies widely, third molar 87 Sr/ 86 Sr, derived from postweaning solid foods, progressively converges to 0.7306 ± 0.0035 (± 2 s.d.), which we express as the local isotopically delineated exploitation area (LIDEA). The spatial resolution of LIDEA is determined using a bioavailable 87 Sr/ 86 Sr isoscape. In this environmental context, we interpret LIDEA as a quantifiable signal indicating eurytopy (generalization), with some 30% of Sr deriving from riparian woodland habitats. With regard to residence, many individuals arrived at the site after second molar mineralization, while some matured locally, demonstrating both male and female dispersal as well as lifelong local residence. Analysis of both 87 Sr/ 86 Sr and the AERs further highlights concomitant patterns, as well as numerous periodicities that may be related to resource depletion, seasonality or lunar cycles. The South African cradle-of-humankind sites of Swartkrans, Krom- draai, Sterkfontein, Drimolen, Cooper’s and Gondolin are located on a narrow band of dolomite, a geological substrate providing strik- ingly different 87 Sr/ 86 Sr than the surrounding intrusive quartzite and granite substrates. Therefore, in this region, 87 Sr/ 86 Sr can viv- idly differentiate local from distal localities and these differences are recorded in teeth 1–5 . These sites are located in a varied biome known as bankenveld characterized by several physiognomic types, including grassland and bushveld in relatively drier soils, and temper- ate microphyllous bushveld and temperate forest along the valley floors and streams 6,7 . Previous study has also demonstrated a clear 87 Sr/ 86 Sr difference between plants growing on the drier grassland/ bushveld from those growing on the Blaaubank stream greenbelt immediately adjacent to Swartkrans, a phenomenon resulting from the dominance of relatively depleted dolomite-derived soluble Sr in stream water 8,9 . Received: 15 March 2025 Accepted: 23 June 2025 Published online: xx xx xxxx Check for updates 1 Department of Anthropology, Rutgers University, New Brunswick, NJ, USA. 2 Centre for Human Evolution Research, Natural History Museum, London, UK. 3 Department of Cell and Developmental Biology, University College London, London, UK. 4 Laboratoire de Géologie de Lyon-Terre, Planètes, Environnement, UMR 5276 CNRS, Ecole Normale Supérieure de Lyon, Université Lyon1, Lyon, France. e-mail: Vincent.Balter@ens-lyon.fr