Acoustic cues to caller identity in lemurs: a case study
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This study investigated the acoustic structure of grunt vocalizations in red-bellied lemurs (Eulemur rubriventer) and its potential for individual discrimination. Acoustic analyses were performed on 1,605 grunts recorded from seven lemurs belonging to two captive groups. From the perspective of sound-filter theory, we described the acoustic structure of grunts, measuring two sets of parameters: fundamental frequency characteristics as larynx-related variables and four formant frequencies as filter-related features. Formants were effective in assigning 80.5% of the vocalizations to the correct emitter against 24.9% scored by the model based on larynx-related variables. We concluded that vocal tract resonances might potentially provide conspecifics with individual cues.
KeywordsEulemur rubriventer Vocalization Vocal tract resonance Formants Discriminant analysis
We thank M. Bonelli for help in data collection, and P. Moisson, D. Gomis, and the Staff at Mulhouse Zoo for granting us access to their lemur groups. This research was supported by the Università degli Studi di Torino and the Ministero dell’Istruzione, dell’Università e della Ricerca. We also thank Dr. Cesare Avesani Zaborra and Parco Natura Viva-Centro Tutela Specie Minacciate for continued support. The authors would also like to express their appreciation to three anonymous reviewers for their constructive comments and suggestions on previous versions of this manuscript.
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