Kangaroo, any of six large species of Australian marsupials noted for hopping and bouncing on their hind legs. The term kangaroo, most specifically used, refers to the eastern gray kangaroo, the western gray kangaroo, and the red kangaroo, as well as to the antilopine kangaroo and two species of wallaroo (see below). Less specifically, kangaroo refers to all 14 species in the genus Macropus, some of which are called wallabies.