Faecal testosterone concentrations and the acoustic behaviour of two captive male Australian fur seals
Joy S. Tripovich A B E , Tracey L. Rogers B C and Geoff Dutton A B DA Faculty of Veterinary Science, University of Sydney, NSW 2006, Australia.
B Australian Marine Mammal Research Centre, Zoological Parks Board of New South Wales/Faculty of Veterinary Science University of Sydney/ School of Biological, Earth and Environmental Sciences, University of NSW, PO Box 20, Mosman, NSW 2088, Australia.
C Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, NSW 2006, Australia.
D Present address: School of Animal and Veterinary Science, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia.
E Corresponding author. Email: joytripovich@hotmail.com
Australian Mammalogy 31(2) 117-122 https://doi.org/10.1071/AM09009
Submitted: 26 March 2009 Accepted: 12 October 2009 Published: 12 November 2009
Abstract
Seasonal changes in reproductive and acoustic behaviour are potentially affected by hormonal fluctuations; however, as it is difficult to routinely sample marine mammals, these associations are mostly inferred. Australian fur seals are vocal marine mammals that have a highly synchronous breeding season. The present study collected information on the testosterone concentration in faeces, vocalisations and behaviour of two captive male Australian fur seals to determine whether there are any associations between these variables. Positive associations were evident between the non-interactive agonistic behaviours (Head sway, Lay down and Head up) and an increase in calling rate of the bark calls in males. Barks were highest during August through to October, corresponding to the breeding period, while faecal testosterone levels peaked in September, coinciding with the high frequency in the calling rates of barks. Guttural threat calls were rarely heard throughout the year, but peaked in August. This call was not frequently heard but was associated with specific behaviours that were produced during more intense fighting interactions. This study presents preliminary information on the vocalisations, behaviour and hormone profiles for two captive Australian fur seals. Future studies with increased sample sizes from both wild and captive animals would clarify the intricate association between these factors.
Additional keywords: hormone, vocalisations, otariids, communication.
Acknowledgements
We thank John Arnould, Sophie Hall Aspland and Kym Collins for their helpful comments on the manuscript. We also thank Andrew Irvine for his kind and generous support in establishing the project. The authors are grateful for the assistance provided by Elle Bombonato and the keepers of the marine mammal department, Taronga Zoo, Zoological Parks Board of New South Wales, Australia, during the collection of samples. Thanks also to the Australian Marine Mammal Research Centre, the Zoological Parks Board of New South Wales and the University of New South Wales for their support of this project. Research for this project was approved by Ethics No. 3a/11/99 Zoological Parks Board of New South Wales.
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