Testing for vocal individual discrimination in adult banded mongooses

Abstract

The ability to individually recognize conspecifics is acknowledged as one of the prerequisites for the development of sophisticated social relationships in group-living species. It has been hypothesized that the discrimination of individual identities is crucial for the maintenance of social relationships and cooperation based on repeated interactions, and for the evolution of many social behaviours. Previous studies have shown that the close calls of the cooperatively breeding banded mongoose Mungos mungo are individually distinct. For instance, banded mongoose pups are able to distinguish between close calls of their escort and of a non-escort. In this study, we used playbacks based on the recently proposed violation-of-expectation paradigm and a dominance/age class recognition setup to investigate whether adult banded mongooses use the individual signature of close calls to distinguish among adult group members. We found no evidence that the individual signature in close calls is used to discriminate identity in banded mongooses. Based on the previous work, we suggest that this is not because banded mongooses are incapable of using signatures as a means of individual discrimination, but because the benefits of such discrimination are low. The study highlights the importance of understanding the function of a signal (e.g. the expected response), timing and the biology of the species when designing and performing playback experiments.