Small mammals are proposed to reflect environmental conditions at high spatial and temporal resolutions due to their small home ranges and short lifespans. The taxonomic abundance of small mammals at fossil and archaeological sites is commonly used as a paleoenvironmental proxy. However, isotopic exploration of small mammals as paleoecological indicators has lagged, primarily due to the lack of comprehensive, ground-truthed data on modern small mammal diet and ecology. This is especially true for eastern African environments, with critical implications for studies of hominin paleoecology. This talk will explore small mammal ecology and diet in modern eastern African ecosystems. I will present stable isotope data (δ13C, δ15N, δ18O) from small mammal teeth and hair from a variety of ecosystems including rainforests, woodlands, wooded grasslands, and grasslands from 16 genera of small mammals. I will discuss potential drivers of small mammal diet, including vegetation availability and climate and will conclude by outlining future directions of this research project and avenues for additional research.