The current thesis was undertaken to investigate the relationship between dietary or environmental factors and tooth wear patterns of two Western chimpanzee populations from West Africa (Taї chimpanzees, Liberian chimpanzees). Macroscopic (cusp wear analysis, OFA) and microscopic (3DST) tooth wear analyses are used to capture wear patterns from long-term and short-term perspectives. In CHAPTER 2, Taї chimpanzee 3DST signals reflect the age-dependent variation in the consumption of phytolith-producing plants rather than varying feeding durations on food categories (e.g. fruits, nuts, leaves) among age groups. Hence, phytoliths as small abrasive particles may be of greater importance for the formation of 3DST patterns than food categories. In CHAPTER 3, 3DST and OFA data are combined to explore the dietary ecology of the Liberian chimpanzees with no detailed dietary records. The results indicate that despite the differences found in the 3DST signals, which are mainly related to the ingestion of dust-covered foods, both populations show similar long-term feeding behaviors as inferred from OFA data. CHAPTER 4 introduces a new technique, macroscopic cusp wear analyses, to investigate whether basic geometric variables can be related to differential tooth use. The results reveal that Taї chimpanzees wear their “multiphase- cusps” more quickly than “single-phase-cusps”, while Liberian chimpanzees exhibit similar degrees of wear on all cusps, suggesting variations in tooth use between both populations. The findings of this thesis demonstrate that a combination of three complementary methods enables the analysis of tooth wear patterns at different temporal scales that would not be discernable with one method alone. Thus, these findings provide important insights into the aspects of tooth wear patterns that are reflected in the dietary ecology of a single subspecies, which further provides important information for future dietary reconstructions in recent and extinct species.