Dear colleagues,

On behalf of my co-authors, I am pleased to announce the publication of a new paper on the social structure of the Australian humpback dolphin, Sousa sahulensis:

Hunt TN, Allen SJ, Bejder L, Parra GJ. 2019. Assortative interactions revealed in a fission-fusion society of Australian humpback dolphins. Behavioral Ecology. 1–14. doi:10.1093/beheco/arz029

Abstract

Understanding individual interactions within a community or population provides valuable insight into its social system, ecology, and, ultimately, resilience against external stimuli. Here, we used photo-identification data, generalized affiliation indices, and social network analyses to investigate dyadic relationships, assortative interactions, and social clustering in the Australian humpback dolphin (Sousa sahulensis). Boat-based surveys were conducted between May 2013 and October 2015 around the North West Cape, Western Australia. Our results indicated a fission–fusion society, characterized by nonrandom dyadic relationships. Assortative interactions were identified both within and between sexes and were higher among members of the same sex, indicating same-sex preferred affiliations and sexual segregation. Assortative interactions by geographic locations were also identified, but with no evidence of distinct social communities or clusters or affiliations based on residency patterns. We noted high residency among females. Models of temporal patterns of association demonstrated variable levels of stability, including stable (preferred companionships) and fluid (casual acquaintances) associations. We also demonstrated some social avoidance. Our results point to greater social complexity than previously recognized for humpback dolphins and, along with knowledge of population size and habitat use, provide the necessary baseline upon which to assess the influence of increasing human activities on this endemic, Vulnerable species.

This paper is available from Behavioral Ecology at https://doi.org/10.1093/beheco/arz029, or if you would like a PDF, please send a request to tim.hunt@flinders.edu.au

Best regards,

Tim

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Tim Hunt, PhD

Cetacean Ecology, Behaviour and Evolution Lab (CEBEL)

College of Science and Engineering

Flinders University of South Australia

( Mob +61 (0)418 946 558| * tim.hunt@flinders.edu.au

: www.cebel.org.au & www.facebook.com/CEBELresearch