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Behavioral Ecology of Singing in the Heart-Nosed Bat, Cardioderma cor
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Although singing has been recently recognized in some bat species, the prevalence and ecological significance of this behavior in bats is still mysterious. Cardioderma cor, the heart-nosed bat, was one of the first bats reported to sing, but little is known about the behavior of this species. Unlike other singing bats, this species roosts in groups during the day but disperses nightly to exclusive foraging areas, whereupon they sing from perches. The goal of this dissertation was to investigate the behavioral ecology of singing in C. cor, addressing key questions such as which bats sing, when and where they sing, and what and why they sing. I conducted a series of experiments to test the hypothesis that C. cor sings to create and defend foraging territories, a behavior commonly observed in songbirds but not mammals. I recorded the singing and sonar behavior of individuals across three field seasons in Tanzania. I mist-netted, tagged, and VHF-tracked 14 individuals to collect movement and singing data. Finally, I conducted acoustic playback experiments with 10 singers. C. cor males showed high fidelity to closely abutting night ranges that varied in size from 0.97 to 5.23 ha. Males foraged early in the evening before singing from preferred perches for up to several hours. I documented two C. cor song types, the most frequent being a “loud” song and less frequently a “soft” song uttered at the height of the dry season. Songs varied within individuals, but each individual’s songs were distinguishable by a unique set of spectral and temporal syllable parameters. C. cor and the sympatric, confamilial yellow-winged bat, Lavia frons, had overlapping foraging territories. However, C. cor’s repertoire was distinctive from that of L. frons’. Song playback experiments with C. cor elicited strong movement responses and changes in singing. Results suggested that song spectral and temporal parameters influenced behavioral responses. The results of this dissertation support the conclusion that C. cor’s singing behavior is consistent with the territory defense hypothesis for the evolution of singing, and suggest that song variability is likely integral to social interactions by facilitating individual discrimination or signaling motivational states.
Smarsh, Grace Christina (2017). Behavioral Ecology of Singing in the Heart-Nosed Bat, Cardioderma cor. Doctoral dissertation, Texas A & M University. Available electronically from