The Rock cavy or mocó (Kerodon rupestris), is a species of cavy endemic to eastern Brazil, from eastern Piauí state to Minas Gerais state. It has been introduced to the oceanic island of Fernando de Noronha. Rock cavies are found in dry, rocky areas with low, scrubby vegetation, and close to stony mountains and hills, resembling another (only distantly related) creature, the Rock hyrax (Procavia capensis). They usually shelter in crevices and the males are territorial, defending rock piles against other adult males.