wallaby, any of several middle-sized marsupial mammals belonging to the kangaroo family, Macropodidae (see kangaroo). They are found chiefly in Australia.
The 11 species of brush wallabies (genus Macropus, subgenus Protemnodon) are built like the big kangaroos but differ somewhat in dentition. Their head and body length is 45 to 105 cm (18 to 41 inches), and the tail is 33 to 75 cm long. A common species is the red-necked wallaby (M. rufogriseus), with reddish nape and shoulders, which inhabits brushlands of southeastern Australia and Tasmania; this species is often seen in zoos. The pretty-faced wallaby, or whiptail (M. elegans, or M. parryi), with distinctive cheek marks, is found in open woods of coastal eastern Australia.
The six named species of rock wallabies (Petrogale) live among rocks, usually near water. They are prettily coloured in shades of brown and gray and are distinguished by stripes, patches, or other markings. They are extremely agile on rocky terrain. The three species of nail-tailed wallabies (Onychogalea) are named for a horny growth on the tail tip. They are handsomely striped at the shoulder. Because they rotate their forelimbs while hopping, they are often called organ-grinders. Two species are endangered.
The two species of hare wallabies (Lagorchestes) are small animals that have the movements and some of the habits of hares. Often called pademelons, the three species of scrub wallabies (Thylogale) of New Guinea, the Bismarck Archipelago, and Tasmania are small and stocky, with short hind limbs and pointy noses. They are hunted for meat and fur. A similar species is the short-tailed scrub wallaby, or quokka (Setonix brachyurus); this species is now restricted to two offshore islands of Western Australia.
The three named species of forest wallabies (Dorcopsulus) are native to the island of New Guinea. The dwarf wallaby is the smallest member of the genus and the smallest known member of the kangaroo family. Its length is about 46 cm (18 inches) from nose to tail, and it weighs about 1.6 kg (3.5 pounds).