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Social organisation and dispersal in the red kangaroo

Oliver, Anthony John (1986) Social organisation and dispersal in the red kangaroo. PhD thesis, Murdoch University.

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Abstract

The management of red kangaroos Macropus rufus has long been of interest to the pastoral community. Although earlier studies of this species revealed no coherent pattern of social organisation, practical difficulties precluded study of known individuals over long time periods. This thesis presents five interlocking studies addressing this deficiency, and ranging from large-scale, low-resolution studies to more intensive work on smaller groups.

Analysis of the movements of over 300 red kangaroos with numbered collars showed that adult females were more sedentary than others, and that sub-adult males were more mobile than adults. Some individuals were very sedentary for up to 5 years while others moved long distances. A more detailed mark-recapture study of nearly 90 individuals over a 26-day period also revealed a disparity in site tenacity between adults and juveniles. Sub-adults dispersed randomly while adults did not. Drought increased dispersal distance in adults.

Radio-tracking studies of 10 adults continuously over 14 consecutive days showed that they had compact home ranges, the cores of which did not overlap. Visits to water were the main excursions. A further group of 24 adults and juveniles, of both sexes, were radio-tracked using aircraft every month for up to two years. This revealed that adult females had long term stable home ranges, including one exclusive core area which is intensely utilised. Adult males occupied larger areas than adult females but, unlike females, did not concentrate their activities in only one part of their range. The core area of the largest males contained the core areas of several adult female home ranges. The core areas of females’ home ranges all contained shelter and grazing. Sub-adults dispersed widely after maternal dependence and settled into an adult behaviour pattern at maturity.

Examination of coat colour and texture in kangaroos from a large part of Western Australia suggested regional adaptation and limited gene flow, consistent with a nonnomadic lifestyle. Coat colour appears regionally adapted to visual predation by dingoes. It is suggested. on the basis of evidence of predation presented, that dingoes (and other predators) have also had a major impact on the evolution of social organisation in the red kangaroo.

The picture that emerges suggests that social organisation in the red kangaroo is comparable with that in some eutherian herbivores, and parallels the complex and finely tuned adaptations to arid zone life shown in other aspects of the biology of red kangaroos.

Item Type: Thesis (PhD)
Murdoch Affiliation: School of Environmental and Life Sciences
Notes: Note to the author: If you would like to make your thesis openly available on Murdoch University Library's Research Repository, please contact: repository@murdoch.edu.au. Thank you.
Supervisor(s): Wooller, Ron and Bradley, Stuart
URI: http://researchrepository.murdoch.edu.au/id/eprint/52624
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