Ingo Arndt / Eastern Grey Kangaroo (Macropus giganteus) joey reaching into mother's pouch, Wilson's Promontory National Park, Australia

D. Parer & E. Parer-Cook / Eastern Grey Kangaroo (Macropus giganteus) juveniles on alert, Maria Island National Park, Tasmania, Australia

Mitsuaki Iwago / Dingo (Canis lupus dingo) resting, introduced species, Australia

Mitsuaki Iwago / Common Brush-tailed Possum (Trichosurus vulpecula) introduced for fur is now the top pest which damages forests and kills birds, Australia

Gerry Ellis / Western Grey Kangaroo (Macropus fuliginosus) portrait, Australia

Mitsuaki Iwago / Red Kangaroo (Macropus rufus) mother with joey standing in tall grass, Sturt National Park, Australia

Mitsuaki Iwago / Red Kangaroo (Macropus rufus) mother with joey in pouch, Australia

Mitsuaki Iwago / Red Kangaroo (Macropus rufus) mother with joey in pouch, Australia

Mitsuaki Iwago / Western Grey Kangaroo (Macropus fuliginosus) pair, Kangaroo Island, Australia

Mitsuaki Iwago / Eastern Grey Kangaroo (Macropus giganteus) sitting in field of tussock grass, Australia

Mitsuaki Iwago / Western Grey Kangaroo (Macropus fuliginosus) pair grazing in tussock grass, Kangaroo Island, Australia

Gerry Ellis / Eastern Grey Kangaroo (Macropus giganteus) jumping through prairie field, Australia