Australian megafauna comprises a large number of animal species in Australia, often defined as species with body mass estimates greater than 45 kg. Many of these species became extinct during the Pleistocene era. Living megafauna include mammals such as the red kangaroo, eastern grey kangaroo, eastern wallaroo, and common wombat; birds such as emus and cassowaries; and reptiles such as goannas and freshwater and saltwater crocodiles.