We describe the vocal repertoire of a facultatively social carnivore, the yellow mongoose, Cynictis penicillata. Using a combination of close-range observations, recordings, and experiments with simulated predators, we were able to obtain clear descriptions of call structure and function for a wide range of calls used by this herpestid. The vocal repertoire of the yellow mongooses comprised ten call types, half of which were used in appeasing or fearful contexts, and half in aggressive interactions. Data from this study suggest that the yellow mongoose uses an urgency-based alarm calling system, indicating high and low urgency through two distinct call types. Compared to solitary mongooses, the yellow mongoose has a large proportion of friendly vocalizations that enhance group cohesion, but its vocal repertoire is smaller and less context-specific than those of obligate social species. This study of the vocal repertoire of the yellow mongoose is, to our knowledge, the mo
st complete to have been conducted on a facultatively social species in its natural habitat.