The fastest kangaroo ever clocked was a female eastern grey at 64 km/h
Red kangaroos get the fame, but the one most Australians actually meet is the eastern grey. It lives close to the big eastern and southern cities, numbers in the millions, and holds the speed record for any kangaroo: a large female once hit 64 kilometres an hour.
George Shaw described the species in 1790 as Macropus giganteus, roughly gigantic large-foot. Among living marsupials and native Australian land mammals, only the red kangaroo outweighs it. Adult males typically weigh 50 to 66 kilograms and carry a tail more than a metre long, while females usually weigh 17 to 40 kilograms. The largest specimen on record, examined by the naturalist Lydekker, weighed 91 kilograms and measured 2.92 metres along the curves of its body.
Telling kangaroos apart takes practice. The eastern grey has a soft light-grey or brownish coat with a paler belly and large, wide-open eyes, and lacks the black and white face markings of the red. Western greys are much harder to separate where the ranges overlap; they are darker, dusty brown and more contrasting around the head. Aboriginal names include iyirrbir in Kunjen and kucha in Pakanha. A Tasmanian population was once split off as its own subspecies, the forester kangaroo, on the basis of coat colour, but a 2003 genetic study found too little difference to justify it, and major authorities no longer recognise the split.
The species thrives in the moister eastern third of the continent, favouring open grassland with bush nearby for daytime shelter, but also turns up in coastal woodland, mountain forest and inland scrub. Like other kangaroos it is most active around dawn and dusk, resting in cover at midday. It grazes a broad mix of grasses and small herbs, eating fewer shrubs than the red.
Social life is loose. Groups average about three animals but merge freely to feed and to rest together in the heat of the day, with a dominance hierarchy deciding who gets the best food and shade, though the animals do not defend territories. Breeding females, animals on the edge of a group and those far from cover stay most alert, and open membership lets newcomers join and add protection against predators.
Source: Eastern grey kangaroo
