Oct 2017 – New publication on sponge presentation in humpback dolphins

We’re very pleased to announce the publication of some of our work on Australian humpback dolphins across north-western Australia. Like Shark Bay’s bottlenose dolphins, this intriguing coastal dolphin species also engages in the manipulation of marine sponges, only this time, it’s got little to do with foraging. Furthermore, we present preliminary evidence of possible alliance formation by pairs of adult male humpback dolphins.

Citation: Allen SJ, King SL, Krützen M & Brown AM 2017. Multi-modal sexual displays in Australian humpback dolphins. Scientific Reports 7: 13644.DOI:10.1038/s41598-017-13898-9.

Link: http://rdcu.be/w3tL

An adult male Australian humpback dolphin with a large marine sponge approaches an adult female with a calf of weaning age in the Dampier Archipelago, Western Australia (photo: Simon Allen).

Abstract: Sexual displays enriched by object carrying serve to increase individual male fitness, yet are uncommon phenomena in the animal kingdom. While they have been documented in a variety of taxa, primarily birds, they are rare outside non-human mammals. Here, we document marine sponge presenting associated with visual and acoustic posturing found in several, geographically widespread populations of Australian humpback dolphins (Sousa sahulensis) over ten years of observation. Only adult males presented marine sponges, typically doing so in the presence of sexually mature females, although social groups predominantly consisted of mixed age and sex classes. Male humpback dolphins appear to be using sponges for signalling purposes in multi-modal sexual displays. Further, based on limited behavioural and genetic data, we hypothesise that pairs of adult male Sousa form at least temporary coalitions or alliances. The use of objects in sexual displays by non-human mammals is rare and, moreover, cooperation between males in the pursuit of an indivisible resource is an evolutionary hurdle relatively few species have overcome. These findings suggest a hitherto unrecognised level of social complexity in humpback dolphins.

Media: There was some nice coverage in Nat Geo at: https://news.nationalgeographic.com/2017/10/dolphins-sex-mating-sponges-courtship/

Two adult male humpback dolphins, one holding a sponge, approach some mother-calf pairs in Cone Bay, Western Australia (photo: Simon Allen).


Funding and acknowledgements: The Australian Marine Mammal Centre, the Western Australian Marine Science Institution, the Department of Parks and Wildlife and the Sea World Research and Rescue Foundation funded the research programs during which these data were accumulated. The Coral Bay and Kimberley Marine Research Stations, Pilbara Ports Authority, Hampton Harbour Boat and Sailing Club and Marine Produce Australia provided logistical support to our research teams. SLK was supported by Society in Science, The Branco Weiss Fellowship, administered by the ETH Zurich. This type of research would not be possible without the generous support of numerous volunteers, research assistants and collaborators contributing to funding and/or data acquisition over numerous projects and field trips. In particular, we thank A. Hodgson, A. Quinn, D. Cagnazzi, D. Chabanne, F. Smith, G. Parra, H. Raudino, J. Fromont, J. Smith, J. Tyne, K. Pollock, L. Bejder, N. Loneragan and T. McMurray. This manuscript represents contribution no. 12 of the Dolphin Innovation Project. Finally, we acknowledge the constructive comments provided by two anonymous reviewers and the handling editor, which improved the clarity of this manuscript. This research was conducted under permits for the scientific use of animals from the Western Australian (WA) Department of Parks and Wildlife, and a firearms licence from the WA Police. The Murdoch University Animal Ethics Committee approved all experimental protocols and the research was carried out following consultation with Murujuga, Bardi Jawi and Dambimangari traditional owners.