Western grey kangaroo  (Macropus fuliginosus)

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

One of the largest and most abundant of all kangaroos, the western grey kangaroo has light grey-brown to dark chocolate-brown fur, a finely-haired muzzle, and large ears, fringed with white hairs (2) (3) (4). The fur is often flecked with grey above and is paler below, with dark feet and forepaws, a black tip to the tail, and buff patches on the legs and forearms (4). The powerful, enlarged hindquarters enable the familiar leaping mode of locomotion, aided by the long tail, which acts as a balance and a rudder (2), and by an ankle which is adapted to prevent the foot rotating sideways, so that the kangaroo cannot twist its ankle while hopping (5). The male western grey kangaroo is much larger than the female (4), with longer and more muscular shoulders and forearms, more heavily clawed forepaws, and thickened skin over the belly, which helps absorb the impact of kicks during fights (5). The adult male also has a strong, curry-like odour, lending it the common name of ‘stinker’ (3).

Two subspecies of western grey kangaroo are recognised (3) (6). Macropus fuliginosus fuliginosus, the Kangaroo Island western grey kangaroo, is a dark sooty brown on the back, with shorter limbs, ears and tail. Macropus fuliginosus melanops is variable across its mainland range, being stockier in the east and south, with darker brown on the head and back, and bluish-grey fur underneath. Although previously divided into two forms, M. f. melanops and M. f. ocydromus, M. f. melanops is now known to form a single, gradually changing population, or cline, across its range (3). The western grey kangaroo can be distinguished from the closely related eastern grey kangaroo, Macropus giganteus, by its browner fur, darker colouration around the head, long dark-coloured ears that are almost hairless behind, and sometimes by a blackish patch around the elbow (3).

The western grey kangaroo, somewhat contrary to its common name, is found throughout the south of Australia, from the Indian Ocean in Western Australia to western Victoria, New South Wales and southern Queensland. M. f. fuliginosus is endemic to Kangaroo Island, off the coast of South Australia, while M. f. melanops occurs on the mainland (1) (2) (3). The range is strongly associated with the southern winter rainfall belt (3), and appears to be expanding in South Australia and New South Wales (1). Its range overlaps that of the eastern grey kangaroo along its extreme eastern edge, in eastern South Australia, western New South Wales and south-western Queensland (7).

This species occurs in open woodland and forest, scrubland, heath and grassland, and is also found in pastureland and in cleared farmland adjacent to native bush (1) (4) (6).

The western grey kangaroo is most active from late afternoon to early morning, resting during the day in the shelter of trees and shrubs. When moving slowly, such as when feeding, kangaroos show an unusual, ‘five-footed’ gait, balancing on the tail and forearms while swinging the hind legs forward (2). The diet of the western grey kangaroo consists mainly of grasses, as well as some herbs, leaves, tree bark and shrubs (2) (4), and it has a high tolerance to certain plant toxins (3).

A social species, the western grey kangaroo usually lives in groups, known as ‘mobs’, of up to 40 to 50 individuals. Old males are usually solitary (4). In the eastern part of its range, the species may mix with groups of eastern grey kangaroos, although the two usually occur separately due to differing habitat preferences (3). During the autumn and winter, male western grey kangaroos live in large groups away from the females and engage in threat displays and fights to establish dominance, with the largest, most dominant males having first access to the females in the spring (8). Although breeding may occur year-round, births usually peak between September and March, after winter rainfall has created maximum vegetation growth (2) (4) (8) (9). After a gestation of just 30 days (2) (4), the single, tiny newborn climbs unaided through the female’s fur and into the forward-facing pouch, where it attaches to one of four teats (4) (5). In common with other marsupials, most development occurs in the pouch, with the young, or ‘joey’, first emerging after around 280 days (8), and suckling until about 17 months old (4). Female western grey kangaroos become sexually mature at around 20 to 36 months, and males at around 20 to 72 months (2). Lifespan in the wild may be up to 20 years (4).

Somewhat unusually for a kangaroo, the female western grey kangaroo does not carry dormant embryos in the uterus while still suckling the first young in the pouch, a behaviour known as embryonic diapause (2) (8). Although the female may become receptive as early as 150 days after giving birth (2) (10), conception does not usually occur until there is enough time before birth for the first young to leave the pouch (2). However, if the first young dies in the pouch, the female can become receptive again in as little as eight days (2) (10). Although the lack of embryonic diapause means that the western grey kangaroo is unable, like other species, to recover quickly from drought by rapidly replacing lost young, its seasonal breeding is an advantage where winter rainfall and new spring growth are predictable (8).

The western grey kangaroo is still abundant over most of its original range, and the population may even been expanding (1), helped in part by the provision of pasture and artificial water sources for domestic livestock, together with a reduction in dingo numbers (2) (3) (5). However, the species may be disadvantaged by the spread of extensive agriculture, particularly where land has been cleared for cereal crops (3), and may also have disappeared from many densely settled areas (2). On Kangaroo Island, M. f. fuliginosus may be subject to habitat loss as human activity increases within its limited range, and many animals are also killed by increasing tourist traffic on the island’s roads (2) (6).

Despite these threats, the western grey kangaroo is so numerous in some areas that it is considered a pest species, viewed as a competitor for pasture and water with domestic sheep and cattle (11) (12). Millions of kangaroos of several species are culled each year, under licence, to prevent damage to crops or pasture (1) (5) (6). In addition, regulated commercial hunting is permitted, with kangaroo meat considered a high quality game meat, low in both fat and cholesterol, and the skins providing a high quality, durable leather. Kangaroo products are sold both within Australia and exported overseas (11). However, there is some controversy over whether kangaroo populations can sustain present hunting levels, especially in the face of increasing human habitat modification and drought (2).

With its wide distribution, large population and presence in many protected areas, the western grey kangaroo is not currently considered at risk of extinction (1). Like other kangaroos, wallabies and wallaroos, the species is protected by law in Australia (1) (12), and hunting is not permitted within protected areas (11). The species also has the longest running monitoring programme of any Australian vertebrate (1). Hunting permits and commercial harvesting are controlled under nationally-approved management plans, which aim to maintain kangaroo populations over their natural range and manage them as a renewable resource, in an ecologically sustainable manner (11) (13) (14) (15). In addition, it has been suggested that farmers be encouraged to shift focus from sheep-rearing to kangaroo harvesting, which may help to reduce land degradation (11). Recommended conservation actions for the Kangaroo Island subspecies also include monitoring the number of animals killed along the island’s roads (6).

As an appealing, well-known and readily identifiable Australian mammal, much controversy and public debate has surrounded the commercial hunting of the western grey kangaroo. This scrutiny has led to close attention being given to appropriate kangaroo management, based on extensive scientific research (12), and, although still controversial, such sustainable use may prove a valuable conservation tool where wildlife and human land-use requirements increasingly conflict.

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

To find out more about the western grey kangaroo and its conservation see: 

• Dawson, T.J. (1995) Kangaroos: Biology of the Largest Marsupials. UNSW Press, Sydney.
• 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

For further information on the conservation of Australian wildlife see:

• Australian Wildlife Conservancy:
  http://www.australianwildlife.org/Home.aspx