Leuchtenberger, C., Sousa-Lima, R., Ribas, C., Magnusson, W. E., & Mourão, G. (2016). Giant otter alarm calls as potential mechanisms for individual discrimination and sexual selection. Bioacoustics, 25(3), 279–291.
Acoustic variation can convey identity information, facilitate social\rinteractions among individuals and may be useful in identifying sex\rand group affiliation of senders. Giant otters live in highly cohesive\rgroups with exclusive territories along water bodies defended by the\rentire group by means of acoustic and chemical signals. Snorts are\rharsh alarm calls, emitted in threat contexts, which commonly elicit\rthe cohesion and the alert behaviour of the members of the group.\rThe aim of this study was to determine whether giant otter snorts\rhave potential to be used for individual discrimination. We tested this\rhypothesis by verifying if the acoustic characteristics of snorts vary\rbetween two study areas, among social groups and individuals, and\rbetween males and females. Snort acoustic variables did not differ\rsignificantly among study areas, but varied significantly among\rgroups, individuals and between sexes, with higher discrimination\rbetween sexes. The frequency of formants (F1–F5) and formant\rdispersion (DF) potentially allow identity coding among groups,\rindividuals and sexes. The stronger sex discrimination of snorts may\rbe related to information on body size carried by formant frequencies\rand dispersion, indicating acoustic sexual dimorphism in giant otters.\rAcoustic differences among groups and individuals are more likely\rlearned, since we did not find evidence for a genetic signal encoded\rin the snort variables measured. We conclude that the snorts carry\rinformation that could be used for individual or group recognition.