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Proc Biol Sci. 2004 May 22; 271(1543): 1043–1049.
PMCID: PMC1691697

Signature-whistle production in undisturbed free-ranging bottlenose dolphins (Tursiops truncatus).


Data from behavioural observations and acoustic recordings of free-ranging bottlenose dolphins (Tursiops truncatus) were analysed to determine whether signature whistles are produced by wild undisturbed dolphins, and how whistle production varies with activity and group size. The study animals were part of a resident community of bottlenose dolphins near Sarasota, Florida, USA. This community of dolphins provides a unique opportunity for the study of signature-whistle production, since most animals have been recorded during capture-release events since 1975. Three mother-calf pairs and their associates were recorded for a total of 141.25 h between May and August of 1994 and 1995. Whistles of undisturbed dolphins were compared with those recorded from the same individuals during capture-release events. Whistles were conservatively classified into one of four categories: signature, probable signature, upsweep or other. For statistical analyses, signature and probable signature whistles were combined into a 'signature' category; upsweep and other whistles were combined into a 'non-signature' category. Both 'signature' and 'non-signature' whistle frequencies significantly increased as group size increased. There were significant differences in whistle frequencies across activity types: both 'signature' and 'non-signature' whistles were most likely to occur during socializing and least likely to occur during travelling. There were no significant interactions between group size and activity type. Signature and probable signature whistles made up ca. 52% of all whistles produced by these free-ranging bottlenose dolphins.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Altmann J. Observational study of behavior: sampling methods. Behaviour. 1974;49(3):227–267. [PubMed]
  • Janik VM. Pitfalls in the categorization of behaviour: a comparison of dolphin whistle classification methods. Anim Behav. 1999 Jan;57(1):133–143. [PubMed]
  • Janik VM. Whistle matching in wild bottlenose dolphins (Tursiops truncatus) Science. 2000 Aug 25;289(5483):1355–1357. [PubMed]
  • Janik VM, Slater PJB. Context-specific use suggests that bottlenose dolphin signature whistles are cohesion calls. Anim Behav. 1998 Oct;56(4):829–838. [PubMed]
  • Sayigh LS, Tyack PL, Wells RS, Solow AR, Scott MD, Irvine AB. Individual recognition in wild bottlenose dolphins: a field test using playback experiments. Anim Behav. 1999 Jan;57(1):41–50. [PubMed]

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