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Age-related multi-year associations in female humpback whales (Megaptera novaeangliae)

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Abstract

Analyses of social structures in baleen whales are rare, and so far, they are thought to consist of mostly short and unstable associations. We investigated the association patterns of individual humpback whales from a summer feeding aggregation in the Gulf of St. Lawrence from 1997 to 2005. Photo-identified animals were sexed using genetic methods and were grouped into five categories: juvenile males/females, mature males and lactating/non-lactating females. We calculated half-weight association indices within and between the groups and found that 45% of the observation showed single animals and another 45% small groups (two to three) consisting mainly of mature animals besides lactating females. Using permutation tests, we found evidence for long-term associations between mature males and non-lactating females as well as among non-lactating females. Standardised lagged association rates revealed that these male–female groups disassociated quickly over about 2 weeks, whereas associations increased again towards the beginning of the breeding season. Non-lactating females of similar age engaged in multi-seasonal stable pairs for up to six consecutive feeding seasons; no mature male–female association was observed in consecutive years. The females with the most stable and long-term associations also had the highest reproductive output. While the risk of predation could not explain these long-term bonds, feeding cooperation seemed the most plausible explanation for group forming behaviour during the summer months.

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References

  • Alexander RD (1974) The evolution of social behavior. Annu Rev Ecol Syst 5:325–383

    Article  Google Scholar 

  • Altmann J, Alberts SC, Haines SA, Dubach J, Muruthi P, Coote T, Geffen E, Cheesman DJ, Mututua RS, Saiyelel SN, Wayne RK, Lacy RC, Bruford MW (1996) Behavior predicts genetic structure in a wild primate group. Proc Natl Acad Sci USA 93:5797–5801

    Article  CAS  PubMed  Google Scholar 

  • Archie EA, Moss CJ, Alberts SC (2006) The ties that bind: genetic relatedness predicts the fission and fusion of social groups in wild African elephants. Proc R Soc Lond B 273:513–522

    Article  CAS  Google Scholar 

  • Baker CS, Herman LM (1984a) Seasonal contrasts in the social behavior of the North Pacific humpback whale. Cetus 5:14–16

    Google Scholar 

  • Baker CS, Herman LM (1984b) Aggressive behavior between humpback whales (Megaptera novaeangliae) wintering in Hawaiian waters. Can J Zool 62:1922–1937

    Article  Google Scholar 

  • Baraff L, Weinrich MT (1993) Separation of humpback whale mothers and calves on a feeding ground in early autumn. Mar Mamm Sci 9:431–434

    Article  Google Scholar 

  • Barton RA, Byrne RW, Whiten A (1996) Ecology, feeding competition and social structure in baboons. Behav Ecol Sociobiol 38:321–329

    Article  Google Scholar 

  • Bejder L, Fletcher D, Bräger S (1998) A method for testing association patterns of social animals. Anim Behav 56:719–725

    Article  PubMed  Google Scholar 

  • Bérubé M, Palsbøll PJ (1996) Identification of sex in cetaceans by multiplexing with three ZFX and ZFY specific primers. Mol Ecol 5:283–287

    PubMed  Google Scholar 

  • Bérubé M, Berchok C, Sears R (2001) Observation of a male-biased sex ratio in the Gulf of St. Lawrence fin whales (Balaenoptera physalus): temporal, geographical, or group structure segregation? Mar Mamm Sci 17:371–381

    Article  Google Scholar 

  • Boinski S (1988) Sex differences in the foraging behavior of squirrel monkeys in a seasonal habitat. Behav Ecol Sociobiol 23:177–186

    Article  Google Scholar 

  • Bon R, Campan R (1996) Unexplained sexual segregation in polygynous ungulates: a defense of an ontogenetic approach. Behav Process 38:131–154

    Article  Google Scholar 

  • Borobia M, Gearing PJ, Simard Y, Gearing JN, Beland P (1995) Blubber fatty-acids of finback and humpback whales from the Gulf of St. Lawrence. Mar Biol 122:341–353

    Article  CAS  Google Scholar 

  • Brown M, Corkeron P (1995) Pod characteristics of migrating humpback whales (Megaptera novaeangliae) off the east Australian coast. Behaviour 132:163–179

    Article  Google Scholar 

  • Brown MR, Corkeron PJ, Hale PT, Schultz KW, Bryden MM (1995) Evidence for a sex-segregated migration in the humpback whale (Megaptera novaeangliae). Proc R Soc Lond B 259:229–234

    Article  CAS  Google Scholar 

  • Burnham KP, Anderson DR (2002) Model selection and multimodel inference: a practical information-theoretic approach, 2nd edn. Springer, Berlin

    Google Scholar 

  • Cairns SJ, Schwager SJ (1987) A comparison of association indices. Anim Behav 35:1454–1469

    Article  Google Scholar 

  • Cerchio S, Jacobsen JK, Cholewiak DM, Falcone EA, Merriwether DA (2005) Paternity in humpback whales, Megaptera novaeangliae: assessing polygyny and skew in male reproductive success. Anim Behav 70:267–277

    Article  Google Scholar 

  • Chittleborough SJ (1965) Dynamics of two populations of humpback whale, Megaptera nodosa (Bonnaterre). Aust J Mar Freshw Res 16:33–128

    Article  Google Scholar 

  • Clapham P (1993) Social organization of humpback whales on a North Atlantic feeding ground. Symp Zool Soc Lond 66:131–145

    Google Scholar 

  • Clapham PJ (1992) Age at attainment of sexual maturity in humpback whales, Megaptera novaeangliae. Can J Zool 70:1470–1472

    Article  Google Scholar 

  • Clapham PJ (2000) The humpback whale: seasonal feeding and breeding in a baleen whale. In: Mann J, Connor RC, Tyack P, Whitehead H (eds) Cetacean societies—field studies of dolphins and whales. University of Chicago Press, Chicago, pp 173–196

    Google Scholar 

  • Clapham PJ, Mayo CA (1987) Reproduction and recruitment of individually identified humpback whales, Megaptera novaeangliae, observed in Massachusetts Bay, 1979–1985. Can J Zool 65:2853–2863

    Article  Google Scholar 

  • Clutton-Brock TH, Parker GA (1995) Sexual coercion in animal societies. Anim Behav 49:1345–1365

    Article  Google Scholar 

  • Clutton-Brock TH, Guinness FE, Albon SD (1982) Red deer. The behaviour and ecology of two sexes. Edinburgh University Press, Scotland

    Google Scholar 

  • Clutton-Brock TH, Albon SD, Guiness FE (1988) Reproductive success in male and female red deer. In: Clutton-Brock TH (ed) Reproductive success. University of Chicago Press, Chicago, pp 325–343

    Google Scholar 

  • Connor RC, Mann J, Tyack P, Whitehead H (1998) Social evolution in toothed whales. Trends Ecol Evol 13:228–232

    Article  Google Scholar 

  • Conradt L (1999) Social segregation is not a consequence of habitat segregation in red deer and feral soay sheep. Anim Behav 57:1151–1157

    Article  PubMed  Google Scholar 

  • Creel S, Creel NM (1995) Communal hunting and pack size in African wild dogs, Lycaon pictus. Anim Behav 50:1325–1339

    Article  Google Scholar 

  • Dawbin WH (1966) The seasonal migratory cycle of humpback whales. In: Norris KS (ed) Whales, dolphins and porpoises. University of California Press, Berkeley, pp 145–170

    Google Scholar 

  • Dolphin WF (1987) Observations of humpback whale, Megaptera novaeangliae—killer whale, Orcinus orca, interactions in Alaska—comparison with terrestrial predator prey relationships. Can Field-Nat 101:70–75

    Google Scholar 

  • Doniol-Valcroze T (2008) Habitat selection and niche characteristics of rorqual whales in the northern Gulf of St. Lawrence (Canada). Ph.D. thesis, McGill University, Montreal, Canada

  • Fabiani A, Galimberti F, Sanvito S, Hoelzel AR (2006) Relatedness and site fidelity at the southern elephant seal, Mirounga leonina, breeding colony in the Falkland Islands. Anim Behav 72:617–626

    Article  Google Scholar 

  • Gabriele CM, Baker C, Perry A, Straley JM (1995) Long-term, repeated associations among humpback whales in Glacier Bay and Icy Strait, Southeastern Alaska. In: Proceedings 11th Biennial Conference on the Biology of Marine Mammals, 14 December–18 December 1995, Orlando, Florida, USA

  • Gabriele CM, Straley JM, Neilson JL (2007) Age at first calving of female humpback whales in southeastern Alaska. Mar Mamm Sci 23:226–239

    Article  Google Scholar 

  • Gaillard JM, Festa-Bianchet M, Yoccoz NG, Loison A, Toigo C (2000) Temporal variation in fitness components and population dynamics of large herbivores. Annu Rev Ecol Syst 31:367–393

    Article  Google Scholar 

  • Gowans S, Whitehead H, Hooker SK (2001) Social organization in northern bottlenose whales, Hyperoodon ampullatus: not driven by deep-water foraging? Anim Behav 62:369–377

    Article  Google Scholar 

  • Hinde RA (1976) Interactions, relationships and social structure. Man 11:1–17

    Article  Google Scholar 

  • Isbell LA (1991) Contest and scramble competition: patterns of female aggression and ranging behavior among primates. Behav Ecol 2:143–155

    Article  Google Scholar 

  • Jaquet N, Browning C, Kibler P, Nilsson P, Risch D, Webster T, Brown MW (2007) Lonely males—gregarious females? Social organization and association patterns of North Atlantic right whales in Cape Cod bay. Abstract. In: Proceedings 17th Biennial conference on the biology of marine mammals, Cape Town, South Africa

  • Jarman PJ (1974) The social organisation of antelope in relation to their ecology. Behaviour 48:215–267

    Article  Google Scholar 

  • Jefferson TA, Stacey PJ, Baird RW (1991) A review of killer whale interactions with other marine mammals—predation to coexistence. Mamm Rev 21:151–180

    Article  Google Scholar 

  • Jurasz CM, Jurasz VP (1979) The feeding modes of the humpback whale, Megaptera novaeangliae, in southeast Alaska. Sci Rep Whales Res Inst 31:69–83

    Google Scholar 

  • Kappeler PM, van Schaik CP (2002) Evolution of primate social systems. Int J Primatol 23:707–740

    Article  Google Scholar 

  • Katona S, Whitehead H (1981) Identifying humpback whales using their natural markings. Polar Rec 20:439–444

    Article  Google Scholar 

  • Katona SK, Beard JA (1990) Population size, migrations and feeding aggregations of the humpback whale (Megaptera novaeangliae) in the western North Atlantic Ocean. Rep Int Whal Comm Spec Issue 12:295–305

    Google Scholar 

  • Krause J, Ruxton GD (2002) Living in groups. Oxford University Press, Oxford

    Google Scholar 

  • Krause S, Mattner L, James R, Guttridge T, Corcoran MJ, Gruber SH, Krause J (2009) Social network analysis and valid Markov chain Monte Carlo tests of null models. Behav Ecol Sociobiol 63:1089–1096

    Article  Google Scholar 

  • Lockyer CH (1984) Review of baleen whale (Mysticeti) reproduction and implication for management. Rep Int Whal Comm Spec Issue 6:27–50

    Google Scholar 

  • Manly BFJ (1995) A note on the analysis of species co-occurrences. Ecology 76:1109–1115

    Article  Google Scholar 

  • Mann J, Connor RC, Tyack P, Whitehead H (2000) Cetacean societies—field studies of dolphins and whales. University of Chicago Press, Chicago

    Google Scholar 

  • Marcoux M, Rendell L, Whitehead H (2007) Indications of fitness differences among vocal clans of sperm whales. Behav Ecol Sociobiol 61:1093–1098

    Article  Google Scholar 

  • Mattila DK, Clapham PJ (1989) Humpback whales, Megaptera novaeangliae, and other cetaceans on Virgin Bank and in the northern Leeward Islands, 1985 and 1986. Can J Zool 67:2201–2211

    Article  Google Scholar 

  • Mattila DK, Clapham PJ, Vasquez O, Bowman RS (1994) Occurrence, population composition, and habitat use of humpback whales in Samana Bay, Dominican Republic. Can J Zool 72:1898–1907

    Article  Google Scholar 

  • McComb K, Moss C, Durant SM, Baker L, Sayialel S (2001) Matriachs as repositories of social knowledge in African elephants. Science 292:491–494

    Article  CAS  PubMed  Google Scholar 

  • McComb K, Reby D, Baker L, Moss C, Sayialel S (2003) Long-distance communication of acoustic cues to social identity in African elephants. Anim Behav 65:317–329

    Article  Google Scholar 

  • Mehta AV, Allen JM, Constantine R, Garrigue C, Jann B, Jenner C, Marx MK, Matkin CO, Mattila DK, Minton G, Mizroch SA, Olavarria C, Robbins J, Russell KG, Seton RE, Steiger GH, Vikingsson GA, Wade PR, Witteveen BH, Clapham PJ (2007) Baleen whales are not important as prey for killer whales (Orcinus orca) in high-latitude regions. Mar Ecol Prog Ser 348:297–307

    Article  Google Scholar 

  • Mitchell CL (1991) Competitive regimes and female bonding in two species of squirrel monkeys (Saimiri oerstedi and S. sciureus). Behav Ecol Sociobiol 28:55–60

    Article  Google Scholar 

  • Mobley JR, Herman LM (1985) Transience of social affiliations among humpback whales (Megaptera novaeangliae) on the Hawaiian wintering grounds. Can J Zool 63:762–772

    Article  Google Scholar 

  • Norris KS, Dohl TP (1980) Behavior of the Hawaiian spinner dolphin, Stenella longirostris. Fish Bull 77:821–849

    Google Scholar 

  • Ottensmeyer CA, Whitehead H (2003) Behavioural evidence for social units in long-finned pilot whales. Can J Zool 81:1327–1338

    Article  Google Scholar 

  • Packer C, Scheel D, Pusey AE (1990) Why lions form groups: food is not enough. Am Nat 136:1–19

    Article  Google Scholar 

  • Palsbøll P, Allen J, Bérubé M, Clapham PJ, Feddersen TP, Hammond PS, Hudson RR, Jorgensen H, Katona S, Larsen AH, Larsen F, Lien J, Mattila DK, Sigurjónsson J, Sears R, Smith T, Sponer R, Stevick P, Øien N (1997) Genetic tagging of humpback whales. Nature 388:767–769

    Article  PubMed  Google Scholar 

  • Payne R, Webb D (1971) Orientation by means of long range acoustic signalling in baleen whales. Ann NY Acad Sci 188:110–141

    Article  CAS  PubMed  Google Scholar 

  • Perry A, Baker C, Herman LM (1990) Population characteristics of individually identified humpback whales in the central and eastern tropical Pacific: a summary and critique. Rep Int Whal Comm Spec Issue 12:307–317

    Google Scholar 

  • Pomilla C, Rosenbaum HC (2006) Estimates of relatedness in groups of humpback whales (Megaptera novaeangliae) on two wintering grounds of the southern hemisphere. Mol Ecol 15:2541–2555

    Article  CAS  PubMed  Google Scholar 

  • Ramp C (2008) Population dynamics and social organisation of humpback whales (Megaptera novaeangliae) in the Gulf of St. Lawrence—a long-term study. Ph.D. thesis, University of Bremen, Germany. http://nbn-resolving.de/urn:nbn:de:gbv:46-diss000111355

  • Ramp C, Berube M, Palsbøll PJ, Hagen W, Sears R (2010) Sex-specific survival in the humpback whale (Megaptera novaeangliae) in the Gulf of St. Lawrence, Canada. Mar Ecol Prog Ser 400:267–276

    Article  Google Scholar 

  • Robbins J (2007) Structure and dynamics of the Gulf of Maine humpback whale population. Ph.D. thesis, University of St. Andrews, Great Britain

  • Rubenstein DI, Hack M (2004) Natural and sexual selection and the evolution of multi-level societies: insights from zebras with comparison to primates. In: Kappeler PM, van Schaik CP (eds) Sexual selection in primates: new and comparative perspectives. Cambridge University Press, Cambridge, pp 266–279

    Chapter  Google Scholar 

  • Ruckstuhl KE, Neuhaus P (2000) Sexual segregation in ungulates: a new approach. Behaviour 137:361–377

    Article  Google Scholar 

  • Ruckstuhl KE, Neuhaus P (2002) Sexual segregation in ungulates: a comparative test of three hypotheses. Biol Rev 77:77–96

    CAS  PubMed  Google Scholar 

  • Sardi KA, Weinrich MT, Connor RC (2005) Social interactions of humpback whale (Megaptera novaeangliae) mother/calf pairs on a North Atlantic feeding ground. Behaviour 142:731–750

    Article  Google Scholar 

  • Sears R, Berchok C, Palsbøll PJ, Doniol-Valcroze T, Ramp C (1999) Gender related structure in blue whale (Balaenoptera musculus) pairs from eastern Canadian waters. Abstract. In: Proceedings of the 13th Biennial Conference of Marine Mammals, Maui, Hawaii, USA

  • Shi J, Dunbar RIM, Buckland D, Miller D (2005) Dynamics of grouping patterns and social segregation in feral goats (Capra hircus) on the Isle of Rum, NW Scotland. Mammalia 69:185–199

    Article  Google Scholar 

  • Silk JB (2007) The adaptive value of sociality in mammalian groups. Phil Trans Roy Soc Lond 362:539–559

    Article  Google Scholar 

  • Silk JB, Alberts SC, Altmann J (2003) Social bonds of female baboons enhance infant survival. Science 302:1231–1234

    Article  CAS  PubMed  Google Scholar 

  • Sourisseau M, Simard Y, Saucier FJ (2006) Krill aggregation in the St. Lawrence system, and supply of krill to the whale feeding grounds in the Estuary from the Gulf. Mar Ecol Prog Ser 314:257–270

    Article  Google Scholar 

  • Steele JH (1976) Patchiness. In: Cushing DH, Walsh JJ (eds) The ecology of the seas. Blackwell Scientific, Oxford, pp 98–115

    Google Scholar 

  • Steiger GH, Calambokidis J (2000) Reproductive rates of humpback whales off California. Mar Mamm Sci 16:220–239

    Article  Google Scholar 

  • Sterck EHM, Watts DP, van Schaik CP (1997) The evolution of female social relationships in nonhuman primates. Behav Ecol Sociobiol 41:291–309

    Article  Google Scholar 

  • Stone GS, Florez-Gonzales L, Katona S (1990) Whale migration record. Nature 346:705

    Article  Google Scholar 

  • Storz JF (1999) Genetic consequences of mammalian social structure. J Mammal 80:553–569

    Article  Google Scholar 

  • Tyack P (1981) Interaction between singing Hawaiian humpback whales and conspecifics nearby. Behav Ecol Sociobiol 8:105–116

    Article  Google Scholar 

  • Tyack P, Whitehead H (1983) Male competition in large groups of wintering humpback whales. Behaviour 83:132–154

    Article  Google Scholar 

  • Valsecchi E, Haie P, Corkeron P, Amos W (2002) Social structure in migrating humpback whales (Megaptera novaeangliae). Mol Ecol 11:507–518

    Article  CAS  PubMed  Google Scholar 

  • van Schaik CP (1989) The ecology of social relationships among female primates. In: Standen V, Foley RA (eds) Comparative socioecology. Blackwell, Oxford, pp 195–218

    Google Scholar 

  • Weinrich M, Martin M, Griffiths R, Bove J, Schilling M (1997) A shift in distribution of humpback whales, Megaptera novaeangliae, in response to prey in the southern Gulf of Maine. Fish Bull 95:826–836

    Google Scholar 

  • Weinrich MT (1991) Stable social associations among humpback whales (Megaptera novaeangliae) in the southern Gulf of Maine. Can J Zool 69:3012–3019

    Article  Google Scholar 

  • Weinrich MT, Kuhlberg AE (1991) Short-term association patterns of humpback whale (Megaptera novaeangliae) groups on their feeding grounds in the southern Gulf of Maine. Can J Zool 69:3005–3011

    Article  Google Scholar 

  • Weinrich MT, Rosenbaum H, Baker C, Blackmer AL, Whitehead H (2006) The influence of maternal lineages on social affiliations among humpback whales (Megaptera novaeangliae) on their feeding grounds in the southern Gulf of Maine. J Hered 97:226–234

    Article  PubMed  Google Scholar 

  • Whitehead H (1983) Structure and stability of humpback whale groups off Newfoundland. Can J Zool 61:1391–1397

    Article  Google Scholar 

  • Whitehead H (1995) Investigating structure and temporal scale in social organizations using identified individuals. Behav Ecol 6:199–208

    Article  Google Scholar 

  • Whitehead H (1996) Babysitting, dive synchrony, and indications of alloparental care in sperm whales. Behav Ecol Sociobiol 38:237–244

    Article  Google Scholar 

  • Whitehead H (1999) Testing association patterns of social animals. Anim Behav 57:F26–F29

    Article  PubMed  Google Scholar 

  • Whitehead H (2007) Program for analyzing social structure. SOCPROG 2.3 (for MATLAB 7.4, release 2007a). Department of Biology, Dalhousie University. (http://whitelab.biology.dal.ca/index.html).73pp

  • Whitehead H (2008) Analyzing animal societies: quantitative methods for vertebrate social analysis. University of Chicago Press, Chicago

    Google Scholar 

  • Whitehead H, Glass C (1985) Orcas (killer whales) attack humpback whales. J Mammal 66:183–185

    Article  Google Scholar 

  • Wilson EO (1975) Sociobiology: the new synthesis. Belknap, Cambridge

    Google Scholar 

  • Wittemyer G, Douglas-Hamilton I, Getz WM (2005) The socioecology of elephants: analysis of the process creating multitiered social structures. Anim Behav 69:1357–1371

    Article  Google Scholar 

  • Wrangham RW (1979) On the evolution of ape social systems. Soc Sci Inf 18:335–368

    Article  Google Scholar 

  • Wrangham RW (1980) An ecological model of female bonded primate groups. Behaviour 75:262–300

    Article  Google Scholar 

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Acknowledgements

We would like to thank the team of the Mingan Island Cetacean Study for the data collection, Hal Whitehead for his extensive help with the analysis and SOCPROG details and Thomas Doniol-Valcroze, Brian Kot, Julien Delarue, Nathalie Jaquet, Jooke Robbins, Marianne Marcoux, Petra Reimann and three anonymous reviewers for comments on the draft. An earlier version of this article was submitted in partial fulfilment of a doctoral thesis at the University of Bremen. The study complies with the laws of Canada. All fieldwork was conducted under permits of the Department of Fisheries and Oceans, Canada.

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Authors and Affiliations

  1. Mingan Island Cetacean Study, 285 rue Green, St. Lambert, J4P 1T3, QC, Canada

    Christian Ramp & Richard Sears

  2. Marine Zoologie (FB2), Universität Bremen (NW2), Postfach 330 440, 28334, Bremen, Germany

    Christian Ramp & Wilhelm Hagen

  3. Department of Genetics, Microbiology and Toxicology, Stockholm University, 106 91, Stockholm, Sweden

    Per Palsbøll & Martine Bérubé

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  1. Christian Ramp
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Correspondence to Christian Ramp.

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Communicated by V. Janik.

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ESM 1

Description of models fitted to the SLAR of the different data sets. Time lag (τ) (PDF 17 kb)

ESM 2

Annual sample size of identified humpback whales in the research area over the study period, divided by sex. Females pooled in the cohort groups were sighted as non-lactating mature females in the study period (1997–2005) (PDF 18 kb)

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Ramp, C., Hagen, W., Palsbøll, P. et al. Age-related multi-year associations in female humpback whales (Megaptera novaeangliae). Behav Ecol Sociobiol 64, 1563–1576 (2010). https://doi.org/10.1007/s00265-010-0970-8

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