Common wallaroo (Macropus robustus)

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Common wallaroo fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
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Common wallaroo description

The common wallaroo is a rather stocky kangaroo with coarse, shaggy fur, a hairless muzzle, a relatively short, thick tail, and a distinctive upright hopping style ^{(2) (3) (4) (5)}. The robust body shape, with shorter limbs than other kangaroos, may be an adaptation for leaping around on rocks, and the short, broad hind feet have roughened soles to give extra grip ⁽⁴⁾. The male common wallaroo is up to twice the size of the female, and has particularly thick-set shoulders and forearms ^{(4) (6)}.

Coat colour varies from reddish-brown to a very dark blue-grey, almost black, and is generally lighter on the underparts ⁽⁴⁾. Four subspecies are recognised, based mainly on colour, size, and genetic differences: Macropus robustus robustus (eastern wallaroo), Macropus robustus erubescens (euro), Macropus robustus woodwardi (northern wallaroo), and Macropus robustus isabellinus (Barrow Island euro). In some areas, M. r. robustus and M. r. erubescens overlap and are thought to hybridise ⁽⁴⁾. The Barrow Island euro, M. r. isabellinus, is the most distinctive of the subspecies, being smaller and stockier, reaching only half the size of the other forms ^{(3) (4)}.

Also known as

euro, hill kangaroo, hill wallaroo.

Size

Male head-body length: 100 - 140 cm ⁽²⁾

Female head-body length: 75 - 100 cm ⁽²⁾

Male tail length: 80 - 90 cm ⁽²⁾

Female tail length: 60 - 70 cm ⁽²⁾

Male weight: average 35 kg ⁽³⁾

Female weight: average 16 kg ⁽³⁾

Common wallaroo biology

The common wallaroo is often solitary, occupying a relatively small, stable home range near to a rocky outcrop or water, and moving out of rough country to graze on grasses and shrubs in adjoining areas ^{(2) (4) (10)}. Small groups sometimes form around favoured resources, but are usually quite loose in size and composition ^{(2) (6)}. The common wallaroo is able to survive harsh conditions by using caves and rocky outcrops for shelter, and appears to be able to go for as much as two to three months without drinking, surviving solely on the water contained in food plants ^{(2) (10)}.

The common wallaroo is believed to be polygynous ⁽⁶⁾ and is an opportunistic breeder, able to breed throughout the year, although often ceasing reproduction during prolonged droughts ^{(2) (9) (11)}. A single, tiny young is born after a gestation period of 30 to 38 days ⁽⁹⁾, after which it climbs, unaided, through the female’s fur and into the pouch, where it attaches to a teat and begins to suckle ⁽¹²⁾. Most development takes place within the pouch, the young common wallaroo emerging after around 231 to 270 days ⁽⁹⁾. The young is suckled for at least 12 to 14 months, with males reaching sexual maturity at around 18 to 20 months in captivity, and females at 14 to 24 months ⁽⁹⁾. Individuals may live for over 18 years in the wild ⁽²⁾.

In a process known as embryonic diapause, the female common wallaroo is able to become pregnant again shortly after giving birth. However, the new embryo remains dormant until the first young is ready to leave the pouch or is lost, after which the embryo resumes development and is born when the pouch is vacant. This unusual form of reproduction, found in many kangaroos, means the female can quickly replace young lost to predators or drought, and can have embryos ready to develop as soon as conditions become favourable ^{(2) (12)}.

Common wallaroo range

The common wallaroo is widely distributed throughout most of Australia, except Tasmania ^{(1) (2)}, although the distribution is rather patchy due to the discontinuous nature of the habitat ⁽⁴⁾. M. r. robustus occurs in eastern Australia, from southern New South Wales to Queensland, M. r. erubescens occurs over much of the drier areas of the continent, from western New South Wales and Queensland, west to the Indian Ocean coast, and M. r. woodwardi occurs across northwestern Australia in the Kimberley and Arnhem Land ⁽⁴⁾. M. r. isabellinus is found only on Barrow Island, off the coast of Western Australia ^{(1) (4) (7)}. The distribution of the three mainland subspecies is more or less continuous and the geographic demarcation between the subspecies is speculative ⁽⁸⁾.

Common wallaroo habitat

Often referred to as a ‘hill kangaroo’, the common wallaroo typically inhabits mountainous areas, rocky hills and steep escarpments, although it may also use stony rises, grasslands and plains ^{(2) (4) (7) (9)}. Caves, overhanging rocks and ledges are often used for shelter, particularly from extreme heat, and as refuges from predation ^{(1) (2) (4) (9)}. The species may also shelter under trees and dense shrubs, especially near streams ⁽¹⁾.

Common wallaroo status

Classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Common wallaroo threats

There are not thought to be any major threats to the common wallaroo ^{(1) (4)}, and the steep, rocky areas it favours help to protect this species to some degree ^{(4) (11)}. In addition, like many other large kangaroo species, the common wallaroo may have benefitted from artificial water sources provided for livestock, as well as a reduction in dingo numbers and the presence of sheep, creating favourable grazing conditions ^{(2) (10) (11) (12)}. Although the common wallaroo is legally culled in some areas for food and skins, and because of alleged damage to pastures and crops ^{(2) (7) (11) (12)}, it is estimated to make up only about three percent of the overall commercial kangaroo quota ⁽⁴⁾. However, there is some controversy over how many kangaroos can be safely harvested, particularly in light of increasing human habitat modification and drought ⁽²⁾.

The Barrow Island euro, M. r. isabellinus, may be more vulnerable than the mainland subspecies, particularly in light of its smaller, isolated population, estimated to number only around 1,800 individuals ^{(4) (7)}. This distinctive subspecies is listed as Vulnerable under the Environmental Protection and Biodiversity Conservation Act 1999 (EPBC Act), with threats including road fatalities and habitat degradation associated with the development of oilfields ^{(3) (5)}. The population has also recently been found to suffer from anaemia and poor condition, possibly related to nutritional stress ^{(1) (7)}.

Common wallaroo conservation

The mainland populations of the common wallaroo are widespread and abundant, and are present in a number of protected areas ⁽¹⁾. Commercial take is regulated under nationally approved management plans ^{(1) (7)}, which aim to maintain populations of common wallaroo in an ecologically sustainable manner ^{(11) (13) (14)}. Barrow Island is also protected as a nature reserve ^{(3) (4)}, although it has an operating oilfield and approval has recently been granted to construct a large liquefied natural gas plant there ⁽¹⁵⁾. Conservation priorities for the vulnerable Barrow Island euro include determining the extent of nutritional stress in the population, continuing with long-term population monitoring, and determining if oil field management can be modified to improve the condition of the euro population. It will also be important to prevent introductions of non-native species, to monitor and improve traffic management to reduce road fatalities, to develop an appropriate fire management strategy, and to restore land impacted by the oil field ^{(5) (7)}.

View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more

To find out more about the conservation of wallaroos, kangaroos and other Australian wildlife see:

• Maxwell, S., Burbidge, A.A. and Morris, K.D. (1996) The 1996 Action Plan for Australian Marsupials and Monotremes. Wildlife Australia, Canberra. Available at:
  http://www.environment.gov.au/biodiversity/threatened/publications/action/marsupials/index.html
• Dawson, T.J. (1995) Kangaroos: Biology of the Largest Marsupials. UNSW Press, Sydney.
• Australian Wildlife Conservancy:
  http://www.australianwildlife.org/Home.aspx

Authentication

Authenticated (29/03/10) by Dr Andrew A. Burbidge, Western Australian Wildlife Research Centre, Department of Environment and Conservation, Perth.

Glossary

Embryonic diapause

Also known as delayed implantation. A reproductive strategy found in some mammals, such as some marsupial, rodent, bear and mustelid species, in which the embryo does not immediately implant in the uterus, but remains dormant, only implanting and continuing development when conditions are favourable. This strategy allows the female to give birth when survival of the offspring is more likely, such as when environmental conditions are more favourable or the previous offspring has been weaned.

Gestation

The state of being pregnant; the period from conception to birth.

Home range

The area occupied by an animal during routine activities, which is not actively defended.

Hybridisation

Cross-breeding between two different species or subspecies.

Polygynous

Mating system in which males have more than one female partner.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

References

1. IUCN Red List (April, 2009)
   http://www.iucnredlist.org/
2. Nowak, R.M. (1991) Walker’s Mammals of the World. The Johns Hopkins University Press, Baltimore and London.
3. Australian Government: Department of the Environment, Water, Heritage and the Arts (May 2009)
   http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=26196
4. Dawson, T.J. (1995) Kangaroos: Biology of the Largest Marsupials. UNSW Press, Sydney.
5. Approved Conservation Advice for Macropus robustus isabellinus (Barrow Island Euro) (May 2009)
   http://www.environment.gov.au/biodiversity/threatened/species/pubs/26196-conservation-advice.pdf
6. Croft, D.B. (1981) Social behaviour of the euro, Macropus robustus (Gould), in the Australian arid zone. Australian Wildlife Research, 8: 13-49.
7. Maxwell, S., Burbidge, A.A. and Morris, K.D. (1996) The 1996 Action Plan for Australian Marsupials and Monotremes. Wildlife Australia, Canberra.
8. Clancy, T.F. and Croft, D.B. (2008) Common wallaroo Macropus robustus. In: Van Dyck, S. and Strahan, R. (Eds.) The Mammals of Australia. Third Edition. New Holland Publishers, Sydney.
9. Poole, W.E. and Merchant, J.C. (1987) Reproduction in captive wallaroos: the eatern wallaroo, Macropus robustus robustus, the euro, M. r. erubescens and the antilopine wallaroo, M. antilopinus. Australian Wildlife Research, 14: 225-242.
10. Ealey, E.H.M. (1967) Ecology of the euro, Macropus robustus (Gould), in north-western Australia. II. Behaviour, movements, and drinking patterns. CSIRO Wildlife Research, 12: 27-51.
11. Department for Environment and Heritage. (2007) The Kangaroo Conservation and Management Plan for South Australia 2008 - 2012. Department for Environment and Heritage, Adelaide. Available at:
    http://www.environment.gov.au/biodiversity/trade-use/sources/management-plans/pubs/sa-kangaroo-08.pdf
12. Macdonald, D.W. (2006) The Encyclopedia of Mammals. Oxford University Press, Oxford.
13. Department of Environment and Conservation. (2006) Draft New South Wales Kangaroo Management Plan 2007 - 2011. Department of Environment and Conservation, Sydney. Available at:
    http://www.nswfarmers.org.au/__data/assets/pdf_file/0009/2160/SUB_Draft_Kangaroo_Management_Plan_2007-2011.pdf
14. Department of Environment and Conservation. (2007) Wildlife Trade Operation for the Euro (Macropus robustus erubescens) in Western Australia 2007-2009. Government of Western Australia Department of Environment and Conservation, Australia.
15. Burbidge, A.A. (March, 2010) Pers. comm.