Olfaction and social cognition in eusocial naked mole-rats, Heterocephalus glaber

Olfaction is the primary sensory modality involved in social cognition among rodents. Eusocial naked mole-rats live in large subterranean colonies with different castes and subcastes of individuals showing unique behavioural profiles. Thus, these animals are constantly faced with social decisions, which are key to colony maintenance and survival. Previous evidence suggests that naked mole-rats use olfaction for colony-level and individual recognition. To explicitly test a role for olfaction in naked mole-rat social decision making, we impaired function of the main olfactory system using zinc sulphate and measured performance in three behavioural paradigms: social dominance, social recognition and olfactory preference. We report that olfactory impairment significantly affected social dominance scores but that body mass was by far the most important variable for this behaviour. We confirm that naked mole-rats perform individual-level social recognition and that they prefer familiar versus unfamiliar colony olfactory cues. Although zinc sulphate decreased chemoinvestigatory behaviour in both the social recognition and olfactory preference paradigms, animals were still able to discriminate between stimuli, demonstrating that the main olfactory system is not necessary for social decision making in this species. A role for the accessory olfactory system is implied, although additional sensory cues, particularly auditory, must also be considered.