Bottlenose dolphins exchange signature whistles when meeting at sea

The bottlenose dolphin, Tursiops truncatus, is one of very few animals that, through vocal learning, can invent novel acoustic signals and copy whistles of conspecifics. Furthermore, receivers can extract identity information from the invented part of whistles. In captivity, dolphins use such signature whistles while separated from the rest of their group. However, little is known about how they use them at sea. If signature whistles are the main vehicle to transmit identity information, then dolphins should exchange these whistles in contexts where groups or individuals join. We used passive acoustic localization during focal boat follows to observe signature whistle use in the wild. We found that stereotypic whistle exchanges occurred primarily when groups of dolphins met and joined at sea. A sequence analysis verified that most of the whistles used during joins were signature whistles. Whistle matching or copying was not observed in any of the joins. The data show that signature whistle exchanges are a significant part of a greeting sequence that allows dolphins to identify conspecifics when encountering them in the wild.

[1]  R. Wells,et al.  Signature–whistle production in undisturbed free–ranging bottlenose dolphins (Tursiops truncatus) , 2004, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[2]  T G Lang,et al.  Swimming Speed of a Pacific Bottlenose Porpoise , 1966, Science.

[3]  Vincent M. Janik,et al.  Chapter 4 Acoustic Communication in Delphinids , 2009 .

[4]  Nobuo Masataka,et al.  Temporal and Structural Analysis of Affiliative Vocal Exchanges in Squirrel Monkeys (Saimiri Sciureus) , 1986 .

[5]  Randall S. Wells,et al.  2. Dolphin Social Complexity: Lessons from Long-Term Study and Life History , 2003 .

[6]  D. Weary,et al.  Great tits classify songs by individual voice characteristics , 1992, Animal Behaviour.

[7]  V. Janik,et al.  Signature whistle shape conveys identity information to bottlenose dolphins. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[8]  Clive K. Catchpole,et al.  Bird song: Biological themes and variations, 2nd ed. , 2008 .

[9]  P. Slater,et al.  Bird Song: Biological Themes and Variations , 1995 .

[10]  Vincent M Janik,et al.  Whistle rates of wild bottlenose dolphins (Tursiops truncatus): influences of group size and behavior. , 2008, Journal of comparative psychology.

[11]  Paul M. Thompson,et al.  ESTIMATING SIZE AND ASSESSING TRENDS IN A COASTAL BOTTLENOSE DOLPHIN POPULATION , 1999 .

[12]  D. K. Caldwell,et al.  The Whistle of the Atlantic Bottlenosed Dolphin (Tursiops truncatus)—Ontogeny , 1979 .

[13]  Volker B Deecke,et al.  Automated categorization of bioacoustic signals: avoiding perceptual pitfalls. , 2005, The Journal of the Acoustical Society of America.

[14]  P. Hammond,et al.  Considering the temporal when managing the spatial: a population range expansion impacts protected areas‐based management for bottlenose dolphins , 2004 .

[15]  K. Cortopassi,et al.  Contact call diversity in wild orange-fronted parakeet pairs, Aratinga canicularis , 2006, Animal Behaviour.

[16]  I. Pepperberg.  The Alex Studies: Cognitive and Communicative Abilities of Grey Parrots , 2000 .

[17]  A mobile acoustic localization system for the study of free‐ranging dolphins during focal follows , 2008 .

[18]  P. Slater,et al.  Vocal Learning in Mammals , 1997 .

[19]  J. Bradbury.  Vocal communication of wild parrots , 2004 .

[20]  William A. Watkins,et al.  Listening to Hawaiian Spinner Porpoises, Stenella cf. Longirostris, with a Three-Dimensional Hydrophone Array , 1974 .

[21]  P. Tyack,et al.  Whistle repertoires of two bottlenosed dolphins, Tursiops truncatus: mimicry of signature whistles? , 1986, Behavioral Ecology and Sociobiology.

[22]  Melba C. Caldwell,et al.  10 – Review of the Signature-Whistle Hypothesis for the Atlantic Bottlenose Dolphin , 1990 .

[23]  Janet Mann Barbara.  BEHAVIORAL DEVELOPMENT IN WILD BOTTLENOSE DOLPHIN NEWBORNS (TURSIOPS SP.) , 1999 .

[24]  P. Tyack,et al.  Whistle sharing in paired male bottlenose dolphins, Tursiops truncatus , 2004, Behavioral Ecology and Sociobiology.

[25]  P. Slater,et al.  Context-specific use suggests that bottlenose dolphin signature whistles are cohesion calls , 1998, Animal Behaviour.

[26]  M. Knörnschild,et al.  Complex vocal imitation during ontogeny in a bat , 2010, Biology Letters.

[27]  Randall Wells,et al.  Bottlenose dolphin (Tursiops truncatus) calves appear to model their signature whistles on the signature whistles of community members , 2004, Animal Cognition.

[28]  Peter L. Tyack,et al.  Animal social complexity : intelligence, culture, and individualized societies , 2003 .

[29]  Randall S. Wells,et al.  Identifying signature whistles from recordings of groups of unrestrained bottlenose dolphins (Tursiops truncatus) , 2013 .

[30]  Ellen C. Garland,et al.  Dynamic Horizontal Cultural Transmission of Humpback Whale Song at the Ocean Basin Scale , 2011, Current Biology.

[31]  Randall S. Wells,et al.  Facts about signature whistles of bottlenose dolphins, Tursiops truncatus , 2007, Animal Behaviour.

[32]  Louis M. Herman,et al.  Representational and conceptual skills of dolphins. , 1993 .

[33]  L M Herman,et al.  Vocal mimicry of computer-generated sounds and vocal labeling of objects by a bottlenosed dolphin, Tursiops truncatus. , 1984, Journal of comparative psychology.

[34]  W. E. Evans,et al.  Observations on Scouting Behavior and Associated Sound Production by the Pacific Bottlenosed Porpoise (Tursiops gilli Dall) , 1962 .

[35]  Randall S. Wells,et al.  Signature whistles of free-ranging bottlenose dolphins Tursiops truncatus: stability and mother-offspring comparisons , 1990, Behavioral Ecology and Sociobiology.

[36]  K. Cortopassi,et al.  Vertical transmission of learned signatures in a wild parrot , 2012, Proceedings of the Royal Society B: Biological Sciences.

[37]  R. Connor,et al.  A division of labour with role specialization in group–hunting bottlenose dolphins (Tursiops truncatus) off Cedar Key, Florida , 2005, Proceedings of the Royal Society B: Biological Sciences.

[38]  P. McGregor,et al.  Female great tits can identify mates by song , 1996, Animal Behaviour.

[39]  R. Seyfarth,et al.  The function and mechanisms underlying baboon ‘contact’ barks , 1996, Animal Behaviour.

[40]  L. Freitag,et al.  Passive acoustic localization of the Atlantic bottlenose dolphin using whistles and echolocation clicks. , 1993, The Journal of the Acoustical Society of America.

[41]  P. J. B. Slater,et al.  Bird Song: Contents , 2008 .

[42]  V. Janik,et al.  Signature whistle variations in a bottlenosed dolphin, Tursiops truncatus , 1994, Behavioral Ecology and Sociobiology.

[43]  Paul M. Thompson,et al.  A TWO‐DIMENSIONAL ACOUSTIC LOCALIZATION SYSTEM FOR MARINE MAMMALS , 2000 .

[44]  V. Janik,et al.  Whistle matching in wild bottlenose dolphins (Tursiops truncatus) , 2000, Science.