acta ethologica

, Volume 19, Issue 2, pp 113–122 | Cite as

Signature whistles in wild bottlenose dolphins: long-term stability and emission rates

  • Ana Rita Luís
  • Miguel N. Couchinho
  • Manuel E. dos Santos
Original Paper


Whistles are key elements in the acoustic repertoire of bottlenose dolphins. In this species, the frequency contours of whistles are used as individual signatures. Assessing the long-lasting stability of such stereotyped signals, and the abundant production of non-stereotyped whistles in the wild, is relevant to a more complete understanding of their biological function. Additionally, studying the effects of group size and activity patterns on whistle emission rate may provide insights into the use of these calls. In this study, we document the decades-long occurrence of whistles with stereotyped frequency contours in a population of wild bottlenose dolphins, resident in the region of the Sado estuary, Portugal. Confirmed stereotypy throughout more than 20 years, and positive identification using the signature identification (SIGID) criteria, suggests that the identified stereotyped whistles are in fact signature whistles. The potential roles of non-stereotyped whistles, which represent 68 % of all whistles recorded, are still unclear and should be further investigated. Emission rates were significantly higher during food-related events. Finally, our data show a comparatively high overall whistle production for this population, and no positive correlation between group size and emission rates, suggesting social or environmental restriction mechanisms in vocal production.


Bottlenose dolphins Tursiops truncatus Acoustic communication Signature whistles Long-term stability Activity patterns Group size 



The authors would like to thank Tróia-Natura S.A. for the financial support in the data collection in 2011. They also thank all the colleagues—Ana Rocha, Sofia Borges, Erica Cruz, Cecília Ferreira, Mafalda Freitas, Vera Mendão, Patrícia Rachinas-Lopes and Erica Sá, and all the students from ISPA—IU who helped in the field work. This study had the support of Fundação para a Ciência e Tecnologia (FCT), through the strategic project UID/MAR/04292/2013 granted to MARE, and the grant awarded to Ana Rita Luís (SFRH/BD/90037/2012).


  1. Acevedo-Gutiérrez A, Stienessen SC (2004) Bottlenose dolphins (Tursiops truncatus) increase number of whistles when feeding. Aquat Mamm 30(3):357–362. doi: 10.1578/AM.30.3.2004.357 CrossRefGoogle Scholar
  2. Au WWL (2004) Echolocation signals of wild dolphins. Acoust Phys 50(4):454–462. doi: 10.1134/1.1776224 CrossRefGoogle Scholar
  3. Augusto JF, Rachinas-Lopes P, dos Santos ME (2012) Social structure of the declining resident community of common bottlenose dolphins in the Sado Estuary, Portugal. J Mar Biol Assoc UK 92(08):1773–1782. doi: 10.1017/S0025315411000889 CrossRefGoogle Scholar
  4. Borker AL, McKown MW, Ackerman JT, Eagles-Smith CA, Tershy BR, Croll DA (2014) Vocal activity as a low cost and scalable index of seabird colony size. Conserv Biol J Soc Conserv Biol 28(4):1100–8. doi: 10.1111/cobi.12264 CrossRefGoogle Scholar
  5. Bouchet H, Blois-Heulin C, Lemasson A (2013) Social complexity parallels vocal complexity: a comparison of three non-human primate species. Front Psychol 4:390. doi: 10.3389/fpsyg.2013.00390 CrossRefPubMedPubMedCentralGoogle Scholar
  6. Bruck JN (2013) Decades-long social memory in bottlenose dolphins. Proc Biol Sci R Soc 280(1768):20131726. doi: 10.1098/rspb.2013.1726 CrossRefGoogle Scholar
  7. Buckstaff KC (2004) Effects of watercraft noise on the acoustic behavior of bottlenose dolphins, Tursiops truncatus, in Sarasota Bay, Florida. Mar Mamm Sci 20(4):709–725. doi: 10.1111/j.1748-7692.2004.tb01189.x CrossRefGoogle Scholar
  8. Caldwell MC, Caldwell DK (1965) Individualized whistle contours in bottle-nosed dolphins (Tursiops truncatus). Nature 207(4995):434–435. doi: 10.1038/207434a0 CrossRefGoogle Scholar
  9. Caldwell MC, Caldwell DK, Tyack PL (1990) Review of the signature-whistle-hypothesis for the Atlantic bottlenose dolphin, Tursiops truncatus. In: Leatherwood S, Reeves RR (eds) The Bottlenose Dolphin. Academic, San Diego, pp 199–234. doi: 10.1016/B978-0-12-440280-5.50014-7 Google Scholar
  10. Casey C, Charrier I, Mathevon N, Reichmuth C (2015) Rival assessment among northern elephant seals: evidence of associative learning during male–male contests. R Soc Open Sci 2(8):150228. doi: 10.1098/rsos.150228 CrossRefPubMedPubMedCentralGoogle Scholar
  11. Clay Z, Smith CL, Blumstein DT (2012) Food-associated vocalizations in mammals and birds: what do these calls really mean? Anim Behav 83:323–330. doi: 10.1016/j.anbehav.2011.12.008 CrossRefGoogle Scholar
  12. Connor RC, Wells RS, Mann J, Read AJ (2000) The bottlenose dolphin: social relationships in a fission-fusion society. In: Mann J, Connor RC, Tyack PL, Whitehead H (eds) Cetacean societies: field studies of dolphins and whales. The University of Chicago Press, Chicago, pp 91–126Google Scholar
  13. Cook MLH, Sayigh LS, Blum JE, Wells RS (2004) Signature-whistle production in undisturbed free-ranging bottlenose dolphins (Tursiops truncatus). Proc Biol Sci R Soc 271(1543):1043–9. doi: 10.1098/rspb.2003.2610 CrossRefGoogle Scholar
  14. Díaz López B (2011) Whistle characteristics in free-ranging bottlenose dolphins (Tursiops truncatus) in the Mediterranean Sea: influence of behaviour. Mamm Biol Z 76(2):180–189. doi: 10.1016/j.mambio.2010.06.006 Google Scholar
  15. Díaz López B, Shirai J (2009) Mediterranean common bottlenose dolphin’s repertoire and communication use. In Pierce L, Correa AG (Eds.) Dolphins: Anatomy, Behavior, and Threats (pp. 129 –148). New York: Nova Science PublishersGoogle Scholar
  16. dos Santos ME, Almada VV (2004) A case for passive sonar: analysis of click train production patterns by bottlenose dolphins in a turbid estuary. In Thomas JA, Moss CF, Vater M (Eds.) Echolocation in bats and dolphins (pp. 400–403). Chicago, IL: University of Chicago PressGoogle Scholar
  17. dos Santos ME, Caporin G, Moreira HO, Ferreira A, Coelho JLB (1990) Acoustic behavior in a local population of bottlenose dolphins. In: Thomas JA, Kastelein RA (eds) Sensory abilities of cetaceans: laboratory and field evidence, vol 196. Springer, Boston, pp 585–598. doi: 10.1007/978-1-4899-0858-2 CrossRefGoogle Scholar
  18. dos Santos ME, Ferreira AJ, Harzen S (1995) Rhythmic sound sequences emitted by aroused bottlenose dolphins in the Sado estuary, Portugal. In Kastelein RA, Thomas JA, Nachtigall PE (Eds.) Sensory Systems of Aquatic Mammals (pp. 325–334). Woerden, the Netherlands: De Spil PublishersGoogle Scholar
  19. dos Santos ME, Louro S, Couchinho M, Brito C (2005) Whistles of bottlenose dolphins (Tursiops truncatus) in the Sado Estuary, Portugal: characteristics, production rates, and long-term contour stability. Aquat Mamm 31(4):453–462. doi: 10.1578/AM.31.4.2005.453 CrossRefGoogle Scholar
  20. Esch HCH, Sayigh LLS, Blum JJE, Wells RSR (2009) Whistles as potential indicators of stress in bottlenose dolphins (Tursiops truncatus). J Mammal 90(3):638–650. doi: 10.1644/08-MAMM-A-069R.1 CrossRefGoogle Scholar
  21. Freeberg TM, Dunbar RIM, Ord TJ (2012) Social complexity as a proximate and ultimate factor in communicative complexity. Philos Trans R Soc B Biol Sci 367:1785–1801. doi: 10.1098/rstb.2011.0213 CrossRefGoogle Scholar
  22. Herman LM (2010) What laboratory research has told us about dolphin cognition. J Comp Psychol 23(3):310–330Google Scholar
  23. Herzing DL (2000) Acoustics and social behavior of wild dolphins: implications for a sound society. In: Au WWL, Fay RR, Popper AN (eds) Hearing by whales and dolphins springer handbook of auditory research, vol 12. Springer New York, New York, pp 225–272. doi: 10.1007/978-1-4612-1150-1 CrossRefGoogle Scholar
  24. Herzing DL (2015) Synchronous and rhythmic vocalizations and correlated underwater behavior of free-ranging Atlantic spotted dolphins (Stenella frontalis) and bottlenose dolphins (Tursiops truncatus) in the Bahamas. Anim Behav Cognit 2(1):14–29Google Scholar
  25. Herzing D, dos Santos M (2004) Functional aspects of echolocation in dolphins. In Thomas JA, Moss CF, Vater M (Eds.) Echolocation in Bats and Dolphins (pp. 386–393). Chicago: University of Chicago PressGoogle Scholar
  26. Hofmeyr-Juritz L, Best P (2011) Acoustic behaviour of southern right whales in relation to numbers of whales present in Walker Bay, South Africa. Afr J Mar Sci 33:415–427. doi: 10.2989/1814232X.2011.637616 CrossRefGoogle Scholar
  27. Hollén LI, Radford AN (2009) The development of alarm call behaviour in mammals and birds. Anim Behav 78(4):791–800. doi: 10.1016/j.anbehav.2009.07.021 CrossRefGoogle Scholar
  28. Hopp SL, Morton ES (1998) Sound Playback Studies. In: Hopp S, Owren M, Evans C (Eds) Animal acoustic communication SE - 10. Springer, Berlin, pp 323–352. doi: 10.1007/978-3-642-76220-8_10
  29. Janik V (1999) Pitfalls in the categorization of behaviour: a comparison of dolphin whistle classification methods. Anim Behav 57(1):133–143. doi: 10.1006/anbe.1998.0923 CrossRefPubMedGoogle Scholar
  30. Janik VM, Sayigh LS (2013) Communication in bottlenose dolphins: 50 years of signature whistle research. J Comp Physiol A 199(6):479–89. doi: 10.1007/s00359-013-0817-7 CrossRefGoogle Scholar
  31. Janik V, Slater P (1998) Context-specific use suggests that bottlenose dolphin signature whistles are cohesion calls. Anim Behav 56(4):829–838Google Scholar
  32. Janik VM, Dehnhardt G, Todt D (1994) Signature whistle variations in a bottlenosed dolphin, Tursiops truncatus. Behav Ecol Sociobiol 35(4):243–248Google Scholar
  33. Janik VM, Sayigh LS, Wells RS (2006) Signature whistle shape conveys identity information to bottlenose dolphins. Proc Natl Acad Sci U S A 103(21):8293–7. doi: 10.1073/pnas.0509918103 CrossRefPubMedPubMedCentralGoogle Scholar
  34. Janik VM, King SL, Sayigh LS, Wells RS (2013) Identifying signature whistles from recordings of groups of unrestrained bottlenose dolphins (Tursiops truncatus). Mar Mamm Sci 29(1):109–122. doi: 10.1111/j.1748-7692.2011.00549.x CrossRefGoogle Scholar
  35. Jensen FH, Bejder L, Wahlberg M, Madsen PT (2009) Biosonar adjustments to target range of echolocating bottlenose dolphins (Tursiops sp.) in the wild. J Exp Biol 212(8):1078–86. doi: 10.1242/jeb.025619 CrossRefPubMedGoogle Scholar
  36. Jones GJ, Sayigh LS (2002) Geographic variation in rates of vocal production of free-ranging bottlenose dolphins. Mar Mamm Sci 18(2):374–393. doi: 10.1111/j.1748-7692.2002.tb01044.x CrossRefGoogle Scholar
  37. Jouventin P, Aubin T (2002) Acoustic systems are adapted to breeding ecologies: individual recognition in nesting penguins. Anim Behav 64(5):747–757. doi: 10.1006/anbe.2002.4002 CrossRefGoogle Scholar
  38. Kershenbaum A, Sayigh LS, Janik VM (2013) The encoding of individual identity in dolphin signature whistles: how much information is needed? PLoS One 8(10):1–7. doi: 10.1371/journal.pone.0077671 CrossRefGoogle Scholar
  39. King SL, Janik VM (2013) Bottlenose dolphins can use learned vocal labels to address each other. Proc Natl Acad Sci U S A 110:13216–21. doi: 10.1073/pnas.1304459110 CrossRefPubMedPubMedCentralGoogle Scholar
  40. King SL, Janik VM (2015) Come dine with me: food-associated social signalling in wild bottlenose dolphins (Tursiops truncatus). Anim Cogn. doi: 10.1007/s10071-015-0851-7 PubMedGoogle Scholar
  41. King SL, Sayigh LS, Wells RS, Fellner W, Janik VM (2013) Vocal copying of individually distinctive signature whistles in bottlenose dolphins. Proc R Soc B Biol Sci 280(1757):20130053. doi: 10.1098/rspb.2013.0053 CrossRefGoogle Scholar
  42. Kriesell HJ, Elwen SH, Nastasi A, Gridley T (2014) Identification and characteristics of signature whistles in wild bottlenose dolphins (Tursiops truncatus) from Namibia. PLoS One 9(9):e106317. doi: 10.1371/journal.pone.0106317 CrossRefPubMedPubMedCentralGoogle Scholar
  43. Lima A, Le Pendu Y (2014) Evidence for signature whistles in Guiana dolphins (Sotalia guianensis) in Ilhéus, northeastern Brazil. J Acoust Soc Am 136(6):3178–3185. doi: 10.1121/1.4900829 CrossRefPubMedGoogle Scholar
  44. Luís AR, Couchinho MN, dos Santos ME (2014) Changes in the acoustic behavior of resident bottlenose dolphins near operating vessels. Mar Mamm Sci 30(4):1417–1426. doi: 10.1111/mms.12125 CrossRefGoogle Scholar
  45. Maciej P, Ndao I, Hammerschmidt K, Fischer J (2013) Vocal communication in a complex multi-level society: constrained acoustic structure and flexible call usage in Guinea baboons. Front Zool 10(1):58. doi: 10.1186/1742-9994-10-58 CrossRefPubMedPubMedCentralGoogle Scholar
  46. Marino L, Connor RC, Fordyce RE, Herman LM, Hof PR, Lefebvre L, Whitehead H (2007) Cetaceans have complex brains for complex cognition. PLoS Biol. doi: 10.1371/journal.pbio.0050139 PubMedPubMedCentralGoogle Scholar
  47. Moreira J, Vukov J, Sousa C, Santos FC, d’Almeida AF, Santos MD, Pacheco JM (2013) Individual memory and the emergence of cooperation. Anim Behav 85(1):233–239. doi: 10.1016/j.anbehav.2012.10.030 CrossRefGoogle Scholar
  48. Mumm CAS, Urrutia MC, Knörnschild M (2014) Vocal individuality in cohesion calls of giant otters, Pteronura brasiliensis. Anim Behav 88:243–252. doi: 10.1016/j.anbehav.2013.12.005 CrossRefGoogle Scholar
  49. Payne KB, Thompson M, Kramer L (2003) Elephant calling patterns as indicators of group size and composition: the basis for an acoustic monitoring system. Afr J Ecol 41(1):99–107. doi: 10.1046/j.1365-2028.2003.00421.x CrossRefGoogle Scholar
  50. Pitcher BJ, Harcourt RG, Charrier I (2010) The memory remains: long-term vocal recognition in Australian sea lions. Anim Cogn 13(5):771–6. doi: 10.1007/s10071-010-0322-0 CrossRefPubMedGoogle Scholar
  51. Quick NJ, Janik VM (2008) Whistle rates of wild bottlenose dolphins (Tursiops truncatus): influences of group size and behavior. J Comp Psychol 122(3):305–11. doi: 10.1037/0735-7036.122.3.305 CrossRefPubMedGoogle Scholar
  52. Radford AN, Ridley AR (2008) Close calling regulates spacing between foraging competitors in the group-living pied babbler. Anim Behav 75(2):519–527. doi: 10.1016/j.anbehav.2007.05.016 CrossRefGoogle Scholar
  53. Sayigh LS, Tyack PL, Wells RS, Scott MD (1990) Signature whistles of free-ranging bottlenose dolphins Tursiops truncatus : stability and mother-offspring comparisons. 247–260Google Scholar
  54. Sayigh L, Tyack P, Wells R, Solow A, Scott M, Irvine A (1999) Individual recognition in wild bottlenose dolphins: a field test using playback experiments. Anim Behav 57(1):41–50. doi: 10.1006/anbe.1998.0961 CrossRefPubMedGoogle Scholar
  55. Sayigh LS, Esch HC, Wells RS, Janik VM (2007) Facts about signature whistles of bottlenose dolphins, Tursiops truncatus. Anim Behav 74(6):1631–1642. doi: 10.1016/j.anbehav.2007.02.018 CrossRefGoogle Scholar
  56. Sharpe LL, Hill A, Cherry MI (2013) Individual recognition in a wild cooperative mammal using contact calls. Anim Behav 86(5):893–900. doi: 10.1016/j.anbehav.2013.07.023 CrossRefGoogle Scholar
  57. Tibbetts EA, Dale J (2007) Individual recognition: it is good to be different. Trends Ecol Evol 22(10):529–537. doi: 10.1016/j.tree.2007.09.001 CrossRefPubMedGoogle Scholar
  58. Watwood S, Owen E, Wells R, Tyack PL (2005) Signature whistle use by temporarily restrained and free-swimming bottlenose dolphins, Tursiops truncatus. Anim Behav 69(6):1373–1386. doi: 10.1016/j.anbehav.2004.08.019 CrossRefGoogle Scholar
  59. Wells RS (2014) Primates and cetaceans. In: Yamagiwa J, Karczmarski L (Eds) Primates and cetaceans: field research and conservation of complex mammalian societies. Springer Verlag, Tokyo, pp 149–172. doi: 10.1007/978-4-431-54523-1
  60. Wells R, Scott M, Irvine AB (1987) The social structure of free-ranging bottlenose dolphins. In: Genoways HH (Eds) Current Mammalogy. Plenum Press, New York, pp 247–305. doi: 10.1007/978-1-4757-9909-5 CrossRefGoogle Scholar
  61. Wiley RH (2013) Specificity and multiplicity in the recognition of individuals: implications for the evolution of social behaviour. Biol Rev 88:179–195. doi: 10.1111/j.1469-185X.2012.00246.x CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg and ISPA 2015

Authors and Affiliations

  • Ana Rita Luís
    • 1
    • 2
  • Miguel N. Couchinho
    • 1
    • 2
  • Manuel E. dos Santos
    • 1
    • 2
  1. 1.MARE—Marine and Environmental Research CentreISPA—Instituto UniversitárioLisbonPortugal
  2. 2.Projecto Delfim—Centro Português de Estudo dos Mamíferos MarinhosLisbonPortugal

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