Primate dental function and evolution: longitudinal 3D tooth wear in wild baboons

Tooth wear constrains feeding efficiency, life history, and survival in mammals, yet its progression in wild populations remains poorly understood. We use high-resolution 3D analysis to quantify occlusal tissue loss over a 3-year period in the upper premolars and molars (P3-M3; n = 70) of wild baboons (Papio). Our sample includes olive baboons (P. anubis) and naturally occurring olive-hamadryas hybrids (P. anubis × P. hamadryas) from Awash National Park, Ethiopia. We calculate mean values for tooth types, visualize tissue loss across occlusal surfaces, and compare individuals by age, sex, and hybrid status. Molars lost tissue faster than premolars (molars: 0.13 mm³/mm²/year; premolars: 0.08 mm³/mm²/year), with the bulk of wear shifting from lingual to buccal cusps in older individuals. The rate of tissue loss did not increase with age, despite greater dentine exposure. There was no clear difference in wear patterns relating to sex or hybrid status, although subtle sex-related differences in P3 wear patterns were observed. These findings demonstrate the adaptive significance of gradual tissue loss in preserving dental function and establish comparative baselines for interpreting wear patterns in extinct primates, where dental remains often provide the primary record of diet and behaviour.