Basic ecological data are missing from the majority of Madagascar’s snakes. We here report seven dietary records from two species of the genus Compsophis and one record from Alluaudina bellyi. Among these are the first records of reptile predation by the former genus, suggesting they are not as strictly anurophagous as heretofore thought. We also report the consumption of a poison frog (Mantella) byaCompsophis, the second reported instance of predation of a member of this genus by a snake, and discuss possible implications for resistance to their alkaloid toxins. The consumption of a small leaf-litter dwelling frog (Stumpffia sp.) by A. bellyi is the first ever diet record for any Alluaudina. We discuss the possible role of niche partitioning between terrestrial and arboreal prey as one of the primary axes of initial divergence between the sister genera Alluaudina and Compsophis, and suggest that differences in their diet may be evident from their dentition, warranting further study.