Koala, tree-dwelling marsupial of eastern coastal Australia. Koala - A Marsupial Mammal. Koala is classified as a marsupial mammal (Mammals whose females have pouch, to … Koala natively belongs to Australia's natural habitat (Queensland and Victoria). The koala is about 60 to 85 cm (24 to 33 inches) long and weighs up to 14 kg (31 pounds) in the southern part of its range but only about half that in subtropical Queensland to the north.Virtually tailless, the body is stout and gray, with a pale yellow or cream-coloured chest and mottling on the rump.