Does sociality imply a complex vocal communication system? A case study for Fukomys micklemi (Bathyergidae, Rodentia)

African mole-rats (Bathyergidae) display different levels of sociality, ranging from solitary to eusocial. To integrate individuals into a social group, communication is necessary. In this study, we examined vocalizations of a social bathyergid, Fukomys micklemi, in order to investigate the relationship between sociality and communication. Because of its social organization and subterranean lifestyle, we expected this species to have an extensive vocal repertoire. Fifteen different adult specific call-types and four juvenile specific call-types could be recognized, similar to those in other social species. A new call-category, linked to submissive behaviour, is described. These submissive calls were exclusively observed in males, indicating their subordinance. The vocal repertoire of F. micklemi was compared with published results on vocalizations in other subterranean rodents, both in social and solitary species. This comparison confirmed the observation that the vocal repertoire of social species is not only more extensive, but also more diverse than that of solitary species.