The eastern grey kangaroo or the great grey kangaroo(Macropus giganteus)
The eastern grey kangaroo (Macropus giganteus) is a marsupial found in the eastern third of Australia, with a population of several million. It is also known as the great grey kangaroo and the forester kangaroo. Although a big eastern grey male can typically weigh up to 66 kg (146 lb) and have a length of well over 2 m (6 ft 7 in), the scientific name, Macropus giganteus (gigantic large-foot), is misleading: the red kangaroo of the semi-arid inland is larger, weighing up to 90 kg (200 lb).
Taxonomy
The eastern grey kangaroo was described by George Shaw in 1790 as Macropus giganteus.
Subspecies
There are two subspecies:
- Macropus giganteus giganteus – found in eastern and central Queensland, Victoria, New South Wales and southeastern South Australia;
- Macropus giganteus tasmaniensis – (commonly known as the forester kangaroo) endemic to Tasmania.
Description
The eastern grey kangaroo is the second largest and heaviest living marsupial and native land mammal in Australia. An adult male will commonly weigh around 50 to 66 kg (110 to 146 lb) whereas females commonly weigh around 17 to 40 kg (37 to 88 lb). They have a powerful tail that is over 1 m (3 ft 3 in) long in adult males. Large males of this species are more heavily built and muscled than the lankier red kangaroo and can occasionally exceed normal dimensions. One of these, shot in eastern Tasmania weighed 82 kg (181 lb), with a 2.64 m (8 ft 8 in) total length from nose to tail (possibly along the curves). The largest known specimen, examined by Lydekker, had a weight of 91 kg (201 lb) and measured 2.92 m (9 ft 7 in) along the curves. When the skin of this specimen was measured it had a "flat" length of 2.49 m (8 ft 2 in).
The eastern grey is easy to recognise: its soft grey coat is distinctive, and it is usually found in moister, more fertile areas than the red. Red kangaroos, though sometimes grey-blue in colour, have a totally different face than eastern grey kangaroos. Red kangaroos have distinctive markings in black and white beside their muzzles and along the sides of their face. Eastern grey kangaroos do not have these markings, and their eyes seem large and wide open.
Where their ranges overlap, it is much more difficult to distinguish between eastern grey and western grey kangaroos, which are closely related. They have a very similar body and facial structure, and their muzzles are fully covered with fine hair (though that is not obvious at a distance, their noses do look noticeably different from the noses of reds and wallaroos). The eastern grey's colouration is a light-coloured grey or brownish-grey, with a lighter silver or cream, sometimes nearly white, belly. The western grey is a dark dusty brown colour, with more contrast especially around the head. Indigenous Australian names include iyirrbir (Uw Oykangand and Uw Olkola) and kucha (Pakanh). The highest ever recorded speed of any kangaroo was 64 km/h (40 mph) set by a large female eastern grey kangaroo.
Habitat and peculiarities
Macropus giganteus is native to eastern and south-western Australia. They are also found in Tasmania, where they prefer to stay in open jungles and densely vegetated plains.
Like all members of its genus, Macropus giganteus is an excellent sportsman. Over short distances they can reach speeds of up to 88 km/h and can leap 9 metres. The average speed is about 50 km/h, but interestingly, kangaroos expend more energy at lower speeds. The grey kangaroo's long tail, about 1.2 m, plays a very important role during movement, used as a balancer and, when the kangaroo is standing, as a support.
Nutrition
The main food of these marsupials is grass and leaves. As the vegetation is very succulent, it almost completely satisfies thirst, and the animal needs little water. Macropus giganteus usually feeds at night, in the morning and in the afternoon, while during the day it shelters from the heat in the shade of trees or in holes it has dug.
Social behaviour and reproduction
Macropus giganteus are social animals. They live in small groups called "mobs". In this case, several groups usually feed together. A "mob" usually has a leader, 2-3 females and several young males. The leader of the pack not only keeps the group in order, but also keeps an eye on the surroundings. If danger appears, Macropus giganteus warns the whole herd by drumming its paws on the ground. The mating season of Macropus giganteus occurs in spring and early summer. Between 30 and 38 days after mating, a calf is born, which at birth measures 2.5 cm and weighs only 1 gram. The calf, although small, burrows into its mother's pouch by itself. Small Macropus giganteus kangaroos remain on milk until they are one and a half years old, after which they begin a fully independent life. The average life expectancy of Macropus giganteus is 18 years.
Status
It is popularly thought, but not confirmed by evidence, that kangaroo populations have increased significantly since the European colonisation of Australia because of the increased areas of grassland (as distinct from forest), the reduction in dingo numbers, and the availability of artificial watering holes. The estimated population of the species Australia-wide in 2010 was 11.4 million. In some places the eastern grey is so numerous it causes overgrazing and some individual populations have been culled in some parts of Australia (see, for example, the Eden Park Kangaroo Cull). Despite the commercial harvest and some culls, the eastern grey remains common and widespread. Eastern greys are common in suburban and rural areas where they have been observed to form larger groups than in natural areas. It still covers the entire range it occupied when Europeans arrived in Australia in 1788 and it often comes into conflict with agriculture as it uses the more fertile districts that now carry crops or exotic pasture grasses, which kangaroos readily eat. Kangaroo meat has also been considered to replace beef in recent years, as their soft feet are preferable to hooves in erosion prone areas.
