A unique feature of Australia's fauna is the relative scarcity of native placental mammals, and dominance of the marsupials – a group of mammals that raise their young in a pouch, including the macropods, possums and dasyuromorphs. The passerines of Australia, also known as songbirds or perching birds, include wrens, the magpie group, thornbills, corvids, pardalotes, lyrebirds. Predominant bird species in the country include the Australian magpie, Australian raven, the pied currawong, crested pigeons and the laughing kookaburra. The koala, emu, platypus and kangaroo are national animals of Australia, and the Tasmanian devil is also one of the well-known animals in the country. The goanna is a predatory lizard native to the Australian mainland.