Object carrying as socio-sexual display in an aquatic mammal

A. R. Martin, V.M.F da Silva, P. Rothery

    Research output: Contribution to journalArticle

    21 Citations (Scopus)

    Abstract

    Amazon river dolphins or botos (Inia geoffrensis Blainville) were observed carrying objects in 221 social groups over a 3-year study period. Sticks, branches and clumps of grass were taken from the water surface and often repeatedly thrashed or thrown. Lumps of hard clay were collected from the river bed and held in the mouth while the carrier rose slowly above the surface and submerged again. Carriers were predominantly adult males and less often subadult males. Adult females and young dolphins rarely carried objects. Groups of dolphins in which object carrying occurred were differentially large and comprised a greater proportion of adult males and adult females. Aggression, mostly between adult males, was significantly associated with object carrying. The behaviour occurred year-round, with peaks in March and July. A plausible explanation of the results is that object carrying by adult males is aimed at females and is stimulated by the number of females in the group, while aggression is targeted at adult males and is stimulated by object carrying in the group. We infer that object carrying in this sexually dimorphic species is socio-sexual display. It is either of ancient origin or has evolved independently in several geographically isolated populations.
    Original languageEnglish
    Pages (from-to)243-245
    JournalBiology Letters
    Volume4
    Issue number3
    DOIs
    Publication statusPublished - 23 Jun 2008

    Fingerprint

    Dolphins
    Mammals
    mammals
    Aggression
    dolphins
    aggression
    Poaceae
    Rivers
    stream channels
    Mouth
    Young Adult
    mouth
    Rosa
    clay
    grasses
    Water
    Population
    water

    Keywords

    • object carrying
    • Amazon river dolphin
    • boto
    • aquatic mammal
    • social behaviour

    Cite this

    Martin, A. R., da Silva, V. M. F., & Rothery, P. (2008). Object carrying as socio-sexual display in an aquatic mammal. Biology Letters, 4(3), 243-245. https://doi.org/10.1098/rsbl.2008.0067
    Martin, A. R. ; da Silva, V.M.F ; Rothery, P. / Object carrying as socio-sexual display in an aquatic mammal. In: Biology Letters. 2008 ; Vol. 4, No. 3. pp. 243-245.
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    abstract = "Amazon river dolphins or botos (Inia geoffrensis Blainville) were observed carrying objects in 221 social groups over a 3-year study period. Sticks, branches and clumps of grass were taken from the water surface and often repeatedly thrashed or thrown. Lumps of hard clay were collected from the river bed and held in the mouth while the carrier rose slowly above the surface and submerged again. Carriers were predominantly adult males and less often subadult males. Adult females and young dolphins rarely carried objects. Groups of dolphins in which object carrying occurred were differentially large and comprised a greater proportion of adult males and adult females. Aggression, mostly between adult males, was significantly associated with object carrying. The behaviour occurred year-round, with peaks in March and July. A plausible explanation of the results is that object carrying by adult males is aimed at females and is stimulated by the number of females in the group, while aggression is targeted at adult males and is stimulated by object carrying in the group. We infer that object carrying in this sexually dimorphic species is socio-sexual display. It is either of ancient origin or has evolved independently in several geographically isolated populations.",
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    note = "Note: First evidence that a mammal other than Man uses objects to wow the girls and intimidate male rivals. Lots of press interest. This work was carried out under successive permits granted to VMFdS by IBAMA (Brazilian National Environmental Agency) and satisfied its criteria on ethics and animal welfare. We thank Instituto Mamirau{\'a} and the financial sponsors of Projeto Boto for their continued support of this long-term project, and the interns who collected data for this analysis.",
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    Martin, AR, da Silva, VMF & Rothery, P 2008, 'Object carrying as socio-sexual display in an aquatic mammal', Biology Letters, vol. 4, no. 3, pp. 243-245. https://doi.org/10.1098/rsbl.2008.0067

    Object carrying as socio-sexual display in an aquatic mammal. / Martin, A. R.; da Silva, V.M.F; Rothery, P.

    In: Biology Letters, Vol. 4, No. 3, 23.06.2008, p. 243-245.

    Research output: Contribution to journalArticle

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