Vocalisations indicate behavioural type in Glossophagine bats

Vocalisations play a crucial role in the social systems of many animals, and may inadvertently reveal behavioural characteristics of the sender. Bats, the second largest mammalian order, rely extensively on vocalisations due to their nocturnal lifestyle and complex social systems, making them ideal for studying links between vocalisations and consistent behavioural traits. In this study, we developed a new testing regime to investigate if consistent individual vocalisation differences in nectarivorous bats are associated with specific behavioural types. We exposed 60 wild, male Glossophaga soricina handleyi bats to novel and risky stressors, and assessed their behavioural and vocal responses. Proactive, exploratory, and bold bats were more likely to produce social calls, and among the vocalising bats, more agitated bats produced higher numbers of social calls. We thus show that bat vocalisation behaviour can be indicative of a certain behavioural type, potentially allowing conspecifics to assess personalities from a distance, which in turn could impact subsequent social interactions, group dynamics, and reproductive success. Our results, in combination with previous findings in birds, suggest that advertent or inadvertent long-distance broadcasting of personality may be widespread, thus opening up new exciting questions about the links between vocalisations and sociality.