Eastern grey kangaroo  (Macropus giganteus)

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

One of the largest kangaroo species (3), the eastern grey kangaroo has soft, thick, grey-brown fur, paler on the underparts, with a finely haired muzzle, and dark tips to the paws, feet and tail (3) (4) (5). There may also be a darker line along the back (3). The length and shading of the fur varies with location, with the subspecies Macropus giganteus tasmaniensis having longer, denser and browner fur than its mainland counterpart, M. g. giganteus (3) (4) (6). The male eastern grey kangaroo is much larger than the female, with a more heavily muscled head, chest and forelimbs, but is otherwise similar in appearance (3) (4).

The eastern grey kangaroo can be distinguished from the closely related western grey kangaroo, Macropus fuliginosus, by its grey rather than brown colouration. The eastern grey kangaroo also has a much paler face, contrasting with a dark eye ring, and has more rounded, shorter and hairier ears (2).

The eastern grey kangaroo has a wide distribution across eastern mainland Australia, from northeast Queensland to southeast South Australia and southern Victoria (1) (2) (3) (4) (5) (7). Subspecies M. g. tasmaniensis occurs in eastern Tasmania, and has also been introduced to Maria Island and Three Hummock Island (1) (6) (8).

The eastern grey kangaroo is found in areas of higher rainfall, including woodland, dry sclerophyll forest, mallee scrub, shrubland and heathland (1) (2) (3) (4) (8). It requires trees or scrub for cover and open areas for feeding (4) (5), and can also occur in agricultural land, introduced grassland and other modified landscapes (1).

The eastern grey kangaroo is mainly active at night, resting in shelter during the heat of the day (1) (2) (4) (5). Like other kangaroos, it is able to travel at great speed, using the powerful, enlarged hindquarters for leaping, aided by the long tail, which acts as a balance and rudder (5). Perhaps surprisingly, kangaroos are also good swimmers (4). The diet consists of grasses, herbs, leaves and other low, shrubby vegetation (2) (6). When alarmed, this kangaroo may thump the hind feet (2). The eastern grey kangaroo is one of the most social of the large kangaroos, often gathering in groups, or ‘mobs’, of 20 or more animals of both sexes and all ages where food is abundant (1) (2) (3) (5) (6). Adult males engage in ritualised fights with rival males (2) (5) (9).

Although breeding may occur year-round, the eastern grey kangaroo usually gives birth in summer, between September and March (2) (3) (5) (7) (10). Like other kangaroos, the young is born at an early stage of development, after a gestation period of just 36 days (5) (11). Tiny, naked and blind, the newborn climbs through the female’s fur and into the forward-facing pouch, where it attaches to a teat to undergo the rest of its development (3) (9). The young eastern grey kangaroo develops more slowly than many other kangaroos, first emerging from the pouch after around 283 days, at a time when food is most available, and finally leaving it completely after around 320 days (3) (5) (7) (11). Usually a single young is born, weighing just over 0.8 grams at birth, although twins are sometimes recorded (3) (5). The young is weaned by about 18 months (5) (11). Females reach sexual maturity at around 20 to 22 months and males at 43 months (5), and lifespan may be up to 25 years in captivity (3).

Many kangaroos are able to conceive again soon after giving birth, the new embryo remaining dormant until the first young is ready to leave the pouch or is lost, a process known as embryonic diapause (5) (9). However, this appears to be rare in the eastern grey kangaroo. If conditions are good, the female eastern grey kangaroo may become receptive and mate from 150 days after giving birth, the embryo then entering diapause, but conception does not usually occur until there is time for the previous young to leave the pouch before the birth of the next. The interval between successive births is therefore approximately one year, and dormant embryos are only occasionally found (3) (5) (7) (12).

There are not believed to be any major threats to the eastern grey kangaroo (1), and the species has often benefitted from human activity, expanding its range where artificial watering holes have been provided for livestock. In many areas, the species is regarded as a pest, and is shot under licence and also hunted commercially for its meat and leather (1) (2) (3) (4) (5) (13). However, in some areas the eastern grey kangaroo population is more limited, particularly in densely settled locations (4) (5), and there is some debate over whether kangaroo populations can sustain present hunting levels (5). State wildlife agencies also cull some locally abundant populations to reduce grazing impacts on native vegetation and to improve animal welfare (2).

There is more concern over the subspecies M. g. tasmaniensis, which has lost over 90 percent of its range due to uncontrolled hunting and habitat loss through agricultural clearing (1) (5) (6) (8) (14). The remaining population is relatively small and fragmented (4) (8) (14), but is now thought to have stabilised (6). However, it is culled under permit due to ongoing conflict with agriculture (6) (8), and is still under threat from land clearance and poaching (8) (14).

The eastern grey kangaroo is present in many protected areas, and is still widespread and abundant (1) (2). The species is protected by law throughout its range (1), and hunting and commercial harvesting are controlled under a range of management plans, which aim to maintain kangaroo populations and manage them as a renewable resource, while attempting to address the conflicts with agriculture (13) (15). Much controversy and debate has surrounded the commercial hunting of kangaroos, but many consider their sustainable use to be a valuable conservation tool (13).

The Tasmanian subspecies, M. g. tasmaniensis, is subject to a number of management measures, and occurs in a number of protected areas in Tasmania. Further conservation actions recommended for this subspecies include continuing to monitor its population levels, continuing to regulate culling, managing habitat within reserves, and using translocation to maintain populations throughout its fragmented and reduced range (6) (8) (14).

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

To find out more about the conservation of this and other kangaroo species 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 more information on conservation in Australia see:

• Australian Government - Department of the Environment, Water, Heritage and the Arts:
  http://www.environment.gov.au/index.html
• Australian Wildlife Conservancy:
  http://www.australianwildlife.org/

For more general information on the eastern grey kangaroo see:

• BBC Wildlife Finder:
  http://www.bbc.co.uk/nature/species/Eastern_Grey_Kangaroo