Dromornis stirtoni Click to enlarge image
Dromornis stirtoni was the largest of the dromornithids, a group of huge flightless birds known only from Australia. The late Miocene Dromornis, from Alcoota Station in the Northern Territory, weighed up to 500kg and stood over three metres in height, making it heavier than the Giant Moa of New Zealand and taller than the Elephant Bird of Madagascar. Image: Anne Musser
© Australian Museum

The late Miocene was a time of global drying and cooling. As ice rapidly accumulated at the poles, sea-levels fell, rainfall decreased and rainforests retreated. Many plant and animal groups died out and other forms, better adapted to a drying world, took their place.

Australia's late Miocene facts


  • Australia was isolated from other landmasses but its northern edge had collided with groups of islands in South East Asia.


  • From the middle Miocene, as polar ice sheets rapidly began to grow in Antarctica, Australia became progressively drier.


  • In the late Miocene, sea-levels dropped. In southern Australia, the Nullarbor Plain - once the limestone bottom of an ancient sea - was exposed.


  • Rainforests retreated to the wetter coastal areas of Australia. Open forests and woodlands were spreading in the drier inland areas.


  • Great herds of large wombat-like marsupials roamed Australia - some had even developed trunks.
  • A new group of kangaroos that hopped began to dominate over their slower four-footed walking relatives.
  • Gigantic thunder birds ruled the Australian roost.
  • The fiercest predators included powerful flesh-eating marsupials called thylacines and lioness-sized marsupial lions.

What was happening in the rest of the world

  • Grasslands were spreading in Africa, Asia and North America.
  • Ancestral forms of apes lived in Africa, Europe and Asia.
  • Like Australia, South America had many marsupial groups, including the ancestors of sabre-toothed marsupials.