acta ethologica

, 11:81 | Cite as

Long-term social structure of long-finned pilot whales (Globicephala melas) in the Strait of Gibraltar

  • R. de StephanisEmail author
  • P. Verborgh
  • S. Pérez
  • R. Esteban
  • L. Minvielle-Sebastia
  • C. Guinet
Original Paper


The Strait of Gibraltar is inhabited by around 216 pilot whales, which are present all year round, and nothing is known about their social structure. The aim of this study is to analyse the inter-individual association patterns within this pilot whales community to (1) provide an insight on their long-term social system and (2) to assess the relationship between sexes within this social system. Between 1999 and 2006, 23,004 km was sampled in the Strait of Gibraltar, and 4,887 images of dorsal fins of pilot whales were taken from 226 groups. The sex of 56 of the individuals could be determined genetically. The strength of the behavioural relationships between dyads of individuals was calculated, and the temporal aspects of the social structure were evaluated, showing in a non-random social structure made by constant companions. The preferred associations between individuals consisted in associations of males–females. Eight long-term units could be found with different degrees of association rates. Consequently, we propose that, in the Strait, the pilot whales exhibit a hierarchical social system composed of a population encompassing several clans of pilot whales each containing several pods. Pods will then be formed by several line units, similar to killer whale matrilineal units.


Pilot whales Social structure Strait of Gibraltar Cetacean 



This project has been financed and subsidised by the General Direction for Biodiversity of the Spanish Ministry of Environment, the Autonomous City of Ceuta (Spain), the Foundation Loro Parque, the Foundation Biodiversidad and the Nature Life Project LIFE02NAT/E/8610 “Conservation of cetaceans and turtles in Murcia and Andalusia” coordinated by the Sociedad Española de Cetáceos. The genetic analysis was supported by grants from the CNRS, the Ministère de la Recherche Scientifique and La Fondation pour la Recherche Médicale/Fondation BNP-Paribas (to L.M.-S.). This work would not have been possible without the help of N. Seller Fernandez, J. Salazar Sierra, Z. Munilla, Y. Yaget, J. de la Fuente and D. Alarcon from CIRCE, and all the Whale watching platforms from the Strait of Gibraltar, WW España, Turmares SL, Aventura Marina and Firmm. This research was conducted using software Logger 2000 developed by the International Fund for Animal Welfare (IFAW) to promote benign and non-invasive research. Thanks are due also to A. Foote for the comments and the language review. Thanks are also due to the three reviewers for their valuable comments to the manuscript. The biopsy sampling complied with the current laws of Spain and was made under the authorisation of the Spanish Ministry of Environment.


  1. Aguilar A, Jover L, Borrell A (1993) Heterogeneities in organochlorine profiles of Faroese long-finned pilot whales: indication of segregation between pods? Rep Int Whal Comm Spec Issue 14:359–367Google Scholar
  2. Akaike H (1974) A new look at the statistical model identification. IEEE Trans Autom Control 19:716–723CrossRefGoogle Scholar
  3. Amos B, Hoelzel AR (1991) Long-term preservation of whale skin for DNA analysis. Genetic ecology of whales and dolphins. Rep Int Whal Comm Spec Issue 13:99–103Google Scholar
  4. Amos B, Barrett J, Dover GA (1991a) Breeding behaviour of pilot whales revealed by DNA fingerprinting. Heredity 67:49–55PubMedCrossRefGoogle Scholar
  5. Amos B, Barrett J, Dover GA (1991b) Breeding system and social structure in the Faroese pilot whale as revealed by DNA fingerprinting. Rep Int Whal Comm Spec Issue 13:255–268Google Scholar
  6. Amos B, Bloch D, Desportes G, Majerus TMO, Bancroft DR, Barrett JA, Dover GA (1993a) A review of the molecular evidence relating to social organisation and breeding system in the long-finned pilot whale. Rep Int Whal Comm Spec Issue 14:209–217Google Scholar
  7. Amos B, Schlötterer C, Tautz D (1993b) Social structure of pilot whales revealed by analytical DNA profiling. Science 260:670–672PubMedCrossRefGoogle Scholar
  8. Andersen LW (1988) Electrophoretic differentiation among local populations of the long-finned pilot whale, Globicephala melaena, at the Faroe Islands. Can J Zool 66:1884–1892Google Scholar
  9. Andersen LW (1993) Further studies on the population structure of the long-finned pilot whale, Globicephala melas, off the Faroe Islands. Rep Int Whal Comm Spec Issue 14:219–231Google Scholar
  10. Auger-Méthé M, Whitehead H (2007) The use of natural markings in studies of long-finned pilot whale (Globicephala melas). Mar Mammal Sci 23:77–93CrossRefGoogle Scholar
  11. Baird RW, Whitehead H (2000) Social organization of mammal-eating killer whales: group stability and dispersal patterns. Can J Zool 78:2096–2105CrossRefGoogle Scholar
  12. Balbuena JA, Raga JA (1994) Intestinal helminths as indicators of segregation and social structure of pods of long-finned pilot whales (Globicephala melas) off the Faeroe Islands. Can J Zool 72:443–448CrossRefGoogle Scholar
  13. Barrett-Lennard LG (2000) Population structure and mating patterns of killer whales, Orcinus orca, as revealed by DNA analysis. Ph.D. thesis, University of British Columbia, VancouverGoogle Scholar
  14. Bejder L, Fletcher D, Bräger S (1998) A method for testing association patterns of social animals. Anim Behav 56:719–725PubMedCrossRefGoogle Scholar
  15. Bigg MA (1982) An assessment of killer whale (Orcinus orca) stocks off Vancouver Island, British Columbia. Rep Int Whal Comm 32:655–666Google Scholar
  16. Bigg MA, Olesiuk PF, Ellis GM, Ford JKB, Balcomb KC (1990) Social organization and genealogy of resident killer whales (Orcinus orca) in the coastal waters of British Columbia and Washington State. Rep Int Whal Comm Special Issue 12:383–405Google Scholar
  17. Cairns SJ, Schwäger SJ (1987) A comparison of association indices. Anim Behav 35:1454–1469CrossRefGoogle Scholar
  18. Cañadas A, Sagarminaga R (2000) The northeastern Alboran Sea, an important breeding and feeding ground for the long finned pilot whale (Globicephala melas) in the Mediterranean Sea. Mar Mammal Sci 16:513–529CrossRefGoogle Scholar
  19. Caurant F, Amiard JC, Amiard-Triquet C, Sauriau PG (1994) Ecological and biological factors controlling the concentrations of trace elements (As, Cd, Cu, Hg, Se, Zn) in delphinids Globicephala melas from the North Atlantic Ocean. Mar Ecol Prog Ser 103:207–219CrossRefGoogle Scholar
  20. Caurant F, Amiard-Triquet C, Amiard JC (1993) Factors influencing the accumulation of metals in pilot whales (Globicephala melas) off the Faroe Islands. Rep Int Whal Comm Spec Issue 14:369–390Google Scholar
  21. Christal J, Whitehead H (2001) Social affiliations within sperm whale (Physeter macrocephalus) groups. Ethology 107:323–340CrossRefGoogle Scholar
  22. Christal J, Whitehead H, Lettevall E (1998) Sperm whale social units: variation and change. Can J Zool 76:1431–1440CrossRefGoogle Scholar
  23. Connor RC (2000) Group living in whales and dolphins. In: Mann J, Connor RC, Tyack PL, Whitehead H (eds) Cetacean societies: field studies of dolphins and whales. University of Chicago Press, Chicago, pp 199–218Google Scholar
  24. de Stephanis R (2008) Estrategias de alimentacio’n de los diferentes grupos de caldero’n comu’n en el Estrecho de Gibraltar. PhD thesis, University of CadizGoogle Scholar
  25. de Stephanis R, Cornulier T, Verborgh P, Salazar Sierra J, Perez Gimeno N, Guinet C (2008) Summer spatial distribution of cetaceans in the Strait of Gibraltar in relation to the oceanographic context. Mar Ecol Prog Ser 353:272–288CrossRefGoogle Scholar
  26. Efron B, Gong G (1983) A leisurely look at the bootstrap, the jackknife, and cross-validation. Am Stat 37:36–48CrossRefGoogle Scholar
  27. Ford JKB (1989) Acoustic behaviour of resident killer whales (Orcinus orca) off Vancouver Island, British Columbia. Can J Zool 67:727–745CrossRefGoogle Scholar
  28. Ford JKB (1991) Vocal traditions among resident killer whales (Orcinus orca) in coastal waters of British Columbia. Can J Zool 69:1454–1483CrossRefGoogle Scholar
  29. Ford JKB, Ellis GM (2002) Reassessing the social organization of resident killer whales in British Columbia Fourth International Orca Symposium and Workshop, France, pp 72–74Google Scholar
  30. Ford JKB, Ellis GM, Balcomb KC (2000) Killer whales, 2nd edn. UBC, VancouverGoogle Scholar
  31. Fullard K (2000) Microsatellite analysis of long-finned pilot whales. PhD thesis, Cambridge University, CambridgeGoogle Scholar
  32. Fullard K, Early G, Heide-Jørgensen MP, Bloch D, Rosing-Asvid A, Amos W (2000) Population structure of long-finned pilot whales in the North Atlantic: a correlation with sea surface temperature? Mol Ecol 9:949–958PubMedCrossRefGoogle Scholar
  33. Ginsberg JR, Young TP (1992) Measuring association between individuals or groups in behavioural studies. Anim Behav 44:377–379CrossRefGoogle Scholar
  34. Gosling LM, Petrie M (1981) The economics of social organization. In: Townsend CR, Calow P (eds) Physiological ecology: an evolutionary approach to resource use. Blackwell Scientific, Oxford, UK, pp 315–345Google Scholar
  35. Greenwood PJ (1980) Mating systems, philopatry, and dispersal in birds and mammals. Anim Behav 28:1140–1162CrossRefGoogle Scholar
  36. Heimlich-Boran JR (1993) Social organization of the short-finned pilot whale, Globicephala macrorhynchus, with special reference to the social ecology of delphinids. PhD thesis, Cambridge University, CambridgeGoogle Scholar
  37. Hinde RA (1976) Interactions, relationships and social structure. Man 11:1–17CrossRefGoogle Scholar
  38. Jankowski M (2005) Long-finned pilot whale movement and social structure: residency, population mixing, and identification of social units, Master’s thesis, Department of Biology, Dalhousie University, Halifax, Nova ScotiaGoogle Scholar
  39. Manly BFJ (1994) Multivariate statistical methods: a primer, 2nd edn. Chapman & Hall, New YorkGoogle Scholar
  40. Ottensmeyer CA, Whitehead H (2003) Behavioural evidence for social units in long-finned pilot whales. Can J Zool 81:1327–1338CrossRefGoogle Scholar
  41. Rosel PE (2003) PCR-based sex determination in Odontocete cetaceans. Conserv Genet 4:647–649CrossRefGoogle Scholar
  42. Sanz JL, Acosta J, Herranz P, Palomo C, San Gil C (1988) Mapa Batimétrico del Estrecho de Girbaltar. Proyecto Hércules 1980–1983, Instituto Español de OceanografíaGoogle Scholar
  43. SEC (Sociedad Española de Cetáceos) (1999) Recopilación, Análisis, Valoración y Elaboración de Protocolos sobre las Labores de Observación, Asistencia a Varamientos y Recuperación de Mamíferos y Tortugas Marinas de las Aguas Españolas. Ministerio de Medio Ambiente Español. Secretaria General de Medio Ambiente, Technical Report Sociedad Española de Cetáceos Available from SEC, Nalón 16, E-28240 Hoyo de Manzanares, Madrid, SpainGoogle Scholar
  44. Shane SH, McSweeney D (1990) Using photo-identification to study pilot whale social organization. Rep Int Whal Comm Spec Issue 12:259–263Google Scholar
  45. Shaw CN, Wilson PJ, White BD (2003) A reliable molecular method of gender determination for mammals. J Mammal 84:123–128CrossRefGoogle Scholar
  46. Verborgh P, de Stephanis R, Pérez S, Yaget J, Barbraud C, Guinet C (2008) Abundance and residency of long-finned pilot whales between 1999 and 2005 in the Strait of Gibraltar. Mar Mammal Sci (in press)Google Scholar
  47. Whitehead H (1995) Investigating structure and temporal scale in social organizations using identified individuals. Behav Ecol 6:199–208CrossRefGoogle Scholar
  48. Whitehead H (1997) Analysing animal social structure. Anim Behav 53:1053–1067CrossRefGoogle Scholar
  49. Whitehead H (1999) Testing association patterns of social animals. Anim Behav 57:F26–F29PubMedCrossRefGoogle Scholar
  50. Zachariassen P (1993) Pilot whale catches in the Faroe Islands, 1709–1992. In: Biology of Northern Hemisphere Pilot Whales. Rep. Int. Whal. Comm, Cambridge, IWC, pp 69–88Google Scholar

Copyright information

© Springer-Verlag and ISPA 2008

Authors and Affiliations

  • R. de Stephanis
    • 1
    Email author
  • P. Verborgh
    • 1
    • 2
  • S. Pérez
    • 1
  • R. Esteban
    • 1
  • L. Minvielle-Sebastia
    • 3
  • C. Guinet
    • 2
  1. 1.CIRCE, Conservation, Information and Research on CetaceansCadizSpain
  2. 2.Centre d’Études Biologiques de ChizéCNRS UPR 1934Villiers en BoisFrance
  3. 3.Institut de Biochimie et Génétique Cellulaires CNRSBordeaux cedexFrance

Personalised recommendations