24
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Individual, unit and vocal clan level identity cues in sperm whale codas

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The ‘social complexity hypothesis’ suggests that complex social structure is a driver of diversity in animal communication systems. Sperm whales have a hierarchically structured society in which the largest affiliative structures, the vocal clans, are marked on ocean-basin scales by culturally transmitted dialects of acoustic signals known as ‘codas’. We examined variation in coda repertoires among both individual whales and social units—the basic element of sperm whale society—using data from nine Caribbean social units across six years. Codas were assigned to individuals using photo-identification and acoustic size measurement, and we calculated similarity between repertoires using both continuous and categorical methods. We identified 21 coda types. Two of those (‘1+1+3’ and ‘5R 1’) made up 65% of the codas recorded, were shared across all units and have dominated repertoires in this population for at least 30 years. Individuals appear to differ in the way they produce ‘5R 1’ but not ‘1+1+3’ coda. Units use distinct 4-click coda types which contribute to making unit repertoires distinctive. Our results support the social complexity hypothesis in a marine species as different patterns of variation between coda types suggest divergent functions, perhaps representing selection for identity signals at several levels of social structure.

          Related collections

          Most cited references19

          • Record: found
          • Abstract: found
          • Article: not found

          Culture in whales and dolphins.

          Studies of animal culture have not normally included a consideration of cetaceans. However, with several long-term field studies now maturing, this situation should change. Animal culture is generally studied by either investigating transmission mechanisms experimentally, or observing patterns of behavioural variation in wild populations that cannot be explained by either genetic or environmental factors. Taking this second, ethnographic, approach, there is good evidence for cultural transmission in several cetacean species. However, only the bottlenose dolphin (Tursiops) has been shown experimentally to possess sophisticated social learning abilities, including vocal and motor imitation; other species have not been studied. There is observational evidence for imitation and teaching in killer whales. For cetaceans and other large, wide-ranging animals, excessive reliance on experimental data for evidence of culture is not productive; we favour the ethnographic approach. The complex and stable vocal and behavioural cultures of sympatric groups of killer whales (Orcinus orca) appear to have no parallel outside humans, and represent an independent evolution of cultural faculties. The wide movements of cetaceans, the greater variability of the marine environment over large temporal scales relative to that on land, and the stable matrilineal social groups of some species are potentially important factors in the evolution of cetacean culture. There have been suggestions of gene-culture coevolution in cetaceans, and culture may be implicated in some unusual behavioural and life-history traits of whales and dolphins. We hope to stimulate discussion and research on culture in these animals.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Social complexity as a proximate and ultimate factor in communicative complexity.

            The 'social complexity hypothesis' for communication posits that groups with complex social systems require more complex communicative systems to regulate interactions and relations among group members. Complex social systems, compared with simple social systems, are those in which individuals frequently interact in many different contexts with many different individuals, and often repeatedly interact with many of the same individuals in networks over time. Complex communicative systems, compared with simple communicative systems, are those that contain a large number of structurally and functionally distinct elements or possess a high amount of bits of information. Here, we describe some of the historical arguments that led to the social complexity hypothesis, and review evidence in support of the hypothesis. We discuss social complexity as a driver of communication and possible causal factor in human language origins. Finally, we discuss some of the key current limitations to the social complexity hypothesis-the lack of tests against alternative hypotheses for communicative complexity and evidence corroborating the hypothesis from modalities other than the vocal signalling channel.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Deep-diving foraging behaviour of sperm whales (Physeter macrocephalus).

              1. Digital tags were used to describe diving and vocal behaviour of sperm whales during 198 complete and partial foraging dives made by 37 individual sperm whales in the Atlantic Ocean, the Gulf of Mexico and the Ligurian Sea. 2. The maximum depth of dive averaged by individual differed across the three regions and was 985 m (SD = 124.3), 644 m (123.4) and 827 m (60.3), respectively. An average dive cycle consisted of a 45 min (6.3) dive with a 9 min (3.0) surface interval, with no significant differences among regions. On average, whales spent greater than 72% of their time in foraging dive cycles. 3. Whales produced regular clicks for 81% (4.1) of a dive and 64% (14.6) of the descent phase. The occurrence of buzz vocalizations (also called 'creaks') as an indicator of the foraging phase of a dive showed no difference in mean prey capture attempts per dive between regions [18 buzzes/dive (7.6)]. Sperm whales descended a mean of 392 m (144) from the start of regular clicking to the first buzz, which supports the hypothesis that regular clicks function as a long-range biosonar. 4. There were no significant differences in the duration of the foraging phase [28 min (6.0)] or percentage of the dive duration in the foraging phase [62% (7.3)] between the three regions, with an overall average proportion of time spent actively encountering prey during dive cycles of 0.53 (0.05). Whales maintained their time in the foraging phase by decreasing transit time for deeper foraging dives. 5. Similarity in foraging behaviour in the three regions and high diving efficiencies suggest that the success of sperm whales as mesopelagic predators is due in part to long-range echolocation of deep prey patches, efficient locomotion and a large aerobic capacity during diving.
                Bookmark

                Author and article information

                Journal
                R Soc Open Sci
                R Soc Open Sci
                RSOS
                royopensci
                Royal Society Open Science
                The Royal Society Publishing
                2054-5703
                January 2016
                20 January 2016
                20 January 2016
                : 3
                : 1
                : 150372
                Affiliations
                [1 ]Zoophysiology, Department of Bioscience, Aarhus University , Aarhus, Jutland, Denmark
                [2 ]Department of Biology, Dalhousie University , Halifax, Canada B3H 4J1
                [3 ]Centre for Social Learning and Cognitive Evolution, and Sea Mammal Research Unit, School of Biology, University of St Andrews , St Andrews KY16 9TH, UK
                Author notes
                Author for correspondence: Shane Gero e-mail: shane.gero@ 123456bios.au.dk
                Article
                rsos150372
                10.1098/rsos.150372
                4736920
                26909165
                57afb4e7-7fdc-48a0-b459-debeb5247ab9

                © 2016 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.

                History
                : 27 July 2015
                : 3 December 2015
                Funding
                Funded by: Ministry of Higher Education and Science of Denmark
                Funded by: Whale and Dolphin Conservation Society
                Funded by: Patrick F. Lett Fund
                Funded by: Marine Alliance for Science and Technology for Scotland
                Award ID: HR09011
                Funded by: Danish Council for Independent Research
                Funded by: Natural Sciences and Engineering Research Council of Canada
                Funded by: Killam Trusts http://dx.doi.org/10.13039/501100004073
                Categories
                1001
                14
                Biology (Whole Organism)
                Research Article
                Custom metadata
                January, 2016

                social complexity hypothesis,conformism,individuality,communication,social structure,cetaceans

                Comments

                Comment on this article