Social behaviour and vocalizations of the tent-roosting Honduran White Bat

Bats are highly gregarious animals, displaying a large spectrum of social systems with different organizational structures. One important factor shaping sociality is group stability. To maintain group cohesion and stability, bats often rely on social vocal communication. The Honduran white bat, Ectophylla alba exhibits an unusual social structure compared to other tent-roosting species. This small white-furred bat lives in perennial stable mixed-sex groups. Tent construction requires several individuals and, as the only tent roosting species so far, involves both sexes. The bats social system and ecology render this species an interesting candidate to study social behaviour and social vocal communication. In our study, we investigated the social behaviour and vocalizations of E. alba in the tent by observing two stable groups, including pups, in the wild. We documented 16 different behaviours, among others, play and fur chewing, a behaviour presumably used for scent-marking. Moreover, we found 10 distinct social call types in addition to echolocation calls, and, for seven call types, we were able to identify the corresponding behavioural context. Most of the social call types were affiliative, including two types of contact calls, maternal directives, pup isolation calls and a call type related to the fur-chewing behaviour. In sum, this study entails an ethogram and describes the first vocal repertoire of a tent-roosting phyllostomid bat, providing the basis for further in-depth studies about the sociality and vocal communication in E. alba.