A wallaroo is any of three closely related species of moderately large macropod, intermediate in size between the kangaroos and the wallabies. The name "wallaroo" is a portmanteau of wallaby and kangaroo. The term is not generally used by Australians. In general, a large, slim-bodied macropod of the open plains is called a "kangaroo"; a small to medium-sized one, particularly if it is relatively thick-set, is a "wallaby": most wallaroos are only a little smaller than a kangaroo, fairly thickset, and are found in open country. All share a particular habit of stance: wrists raised, elbows tucked close into the body, and shoulders thrown back, and all have a large, black-skinned rhinarium.
The best-known species is 'Macropus robustus', which is known as the Wallaroo. Macropus robustus robustus - or Eastern Wallaroo - occupies the slopes of the Great Dividing Range (which runs for more than 3,000 km around the eastern and south-eastern coast of Australia), and the Euro - Macropus robustus erubescens - can be found westward of the Great Dividing Range. There are actually four subspecies of the Wallaroo: the Eastern Wallaroo and the Euro, which are both widespread, and two of more restricted range, one from Barrow Island, the other from the Kimberley.
The Black Wallaroo (Macropus bernardus) occupies an area of steep, rocky ground in Arnhem Land. At around 60 to 70 cm in length (excluding tail) it is the smallest wallaroo and the most heavily built. Males weigh 19 to 22 kg, females about 13 kg. Because it is very wary and is found only in a small area of remote and very rugged country, it is remarkably little known.
The Antilopine Wallaroo (Macropus antilopinus) is the exception among wallaroos. It is, essentially, the far-northern equivalent of the Eastern and Western Grey Kangaroos. Like them, it is a creature of the grassy plains and woodlands, and gregarious, where the other wallaroos are solitary. Because of this difference, it is sometimes called the Antilopine Kangaroo.