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Evolutionary, molecular and comparative zoology
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RESEARCH ARTICLE
Contents Vol 54(3)

Evolution of sexual segregation in mammalian herbivores: kangaroos as marsupial models

G. Coulson A C , A. M. MacFarlane A , S. E. Parsons A B and J. Cutter A
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- Author Affiliations

A Department of Zoology, The University of Melbourne, Vic. 3010, Australia.

B Current address: Lower Murray–Darling Catchment Management Authority, Buronga, NSW 2739, Australia.

C Corresponding author. Email: gcoulson@unimelb.edu.au

Australian Journal of Zoology 54(3) 217-224 https://doi.org/10.1071/ZO05062
Submitted: 24 September 2005  Accepted: 24 April 2006   Published: 22 June 2006

Abstract

Sexual segregation is best known in sexually dimorphic ungulates. Many hypotheses have been proposed to explain the evolution of sexual segregation in ungulates, but all are reducible to the influence of two factors: body size and sex-specific reproductive strategy. Definitive tests of these hypotheses are lacking in ungulates because these factors are confounded, all males being somewhat larger than females. Kangaroos represent a parallel radiation of terrestrial herbivores, but their populations are composed of a spectrum of adult body sizes, ranging from small males the same size as females to large males more than twice the size. We exploited this heteromorphism to assess the independent influences of size and sex in these ungulate analogues. We conducted a preliminary study of western grey kangaroos (Macropus fuliginosus) in north-western Victoria, Australia. Adult males predominately occupied grassland habitat, whereas females occurred mostly in lakebed, woodland and shrubland. Single-sex groups occurred more often than expected during the non-mating season. The diet of large males had the highest proportion of grass, and females had the least. These initial results indicate that both size and sex influence segregation in this species, confirming the worth of kangaroos as marsupial models for research into the evolution of sexual segregation.


Acknowledgments

Parks Victoria staff at Hattah-Kulkyne National Park were generous with their time, particularly Phil Murdoch, as well as David Bone, David Christian and Danielle McLennan. Bill Barker shot the kangaroos with professionalism and patience, and Turi Berg helped with habitat surveys. Scott Laidlaw and Steve Mueck assisted with vegetation identification and analysis. Fred de Munk and David Paul advised us on slide preparation and imaging. Helena Bender, Kirstin Long, Grainne Maguire, Genevieve Morris, Marissa Parrott and Alexa Ryhorchuk offered sound advice and scrutinised drafts. We also thank Ruth, Phil, Nick and Marc for their support. All work in the park was carried out under Department of Natural Resources and Environment research permit 10001674 in accordance with the Code of Practice for the Humane Shooting of Kangaroos, endorsed by the Council of Nature Conservation Ministers (ANPWS 1995). This project was funded by a grant (S1991097) from the Australian Research Council to Graeme Coulson, and an Australian Postgraduate Award to Abigail MacFarlane.


References

Ardia, D. R. , and Bildstein, K. L. (1997). Sex-related differences in habitat selection in wintering American kestrels, Falco sparverius. Animal Behaviour 53, 1305–1311.
| Crossref | GoogleScholarGoogle Scholar | PubMed | Estes R. D. (1991). ‘The Behaviour Guide to African Mammals. Including Hoofed Mammals, Carnivores and Primates.’ (University of California Press: Berkley, CA.)

Everitt B. S. (1977). ‘The Analysis of Contingency Tables.’ (Chapman and Hall: London.)

Ginnett, T. F. , and Demment, M. W. (1999). Sexual segregation by Masai giraffes at two spatial scales. African Journal of Ecology 37, 93–106.
| Crossref | GoogleScholarGoogle Scholar | Jarman P. J., and Coulson G. (1989). Dynamics and adaptiveness of grouping in macropods. In ‘Kangaroos, Wallabies and Rat-kangaroos’. (Eds G. Grigg, P. Jarman and I. Hume.) pp. 527–547. (Surrey Beatty: Sydney.)

Jarman P. J., and Phillips C. M. (1989). Diets in a community of macropod species. In ‘Kangaroos, Wallabies and Rat-kangaroos’. (Eds G. Grigg, P. Jarman and I. Hume.) pp. 143–149. (Surrey Beatty: Sydney.)

Jarman P. J., and Southwell C. J. (1986). Grouping, associations, and reproductive strategies in eastern grey kangaroos. In ‘Ecological Aspects of Social Evolution’. (Eds D. I. Rubenstein and R. W. Wrangham.) pp. 399–428. (Princeton University Press: Princeton, MA.)

Kaufmann, J. H. (1975). Field observations of the social behaviour of the eastern grey kangaroo, Macropus giganteus. Animal Behaviour 23, 214–221.
| Crossref | GoogleScholarGoogle Scholar | MacFarlane A. M., and Coulson G. (2005). Sexual segregation in Australian marsupials. In ‘Sexual Segregation in Vertebrates: the Ecology of the Two Sexes’. (Eds K. E. Ruckstuhl and P. Neuhaus.) pp. 254–279. (Cambridge University Press: Cambridge.)

Main, M. B. , Weckerly, F. W. , and Bleich, V. (1996). Sexual segregation in ungulates: new directions for research. Journal of Mammalogy 77, 449–461.
Norbury G. L. (1987). Diet selection and demography of the western grey kangaroo, Macropus fuliginosus melanops (Desmarest) in Hattah-Kulkyne National Park, Victoria. Ph.D. Thesis, Monash University, Melbourne.

Norbury, G. L. (1988). Microscopic analysis of herbivore diets – a problem and a solution. Australian Wildlife Research 15, 51–57.
| Crossref | GoogleScholarGoogle Scholar | Sluiter I. R. K., Allen G. G., Morgan D. G., and Walker I. S. (1997). Vegetation responses to stratified kangaroo grazing pressure at Hattah-Kulkyne National Park, 1992–96. Flora and Fauna Technical Report No. 149. Department of Natural Resources and Environment, Melbourne.

Stewart, B. S. (1997). Ontogeny of differential migration and sexual segregation in northern elephant seals. Journal of Mammalogy 78, 1101–1116.


Storr, G. M. (1961). Microscopic analysis of faeces, a technique for ascertaining the diet of herbivorous mammals. Australian Journal of Biological Sciences 14, 157–165.


Weckerly, F. W. (1998). Sexual-size dimorphism: influence of mass and mating systems in the most dimorphic mammals. Journal of Mammalogy 79, 33–52.


Wielgus, R. B. , and Bunnell, F. L. (1995). Tests of hypotheses for sexual segregation in grizzly bears. Journal of Wildlife Management 59, 552–560.