Diprotodon skull Click to enlarge image
The massive Diprotodon optatum, from the Pleistocene of Australia, was the largest marsupial known and the last of the extinct, herbivorous diprotodontids. Diprotodon skull from Tambar Springs. Image: John Fields
© Australian Museum

During the Pliocene, the world's continents were close to their present positions. There was an overall cooling of sea and land temperatures. Grasslands were spreading. Australia's plants and animals began to gain their distinctive modern appearance.

Australia's Pliocene facts


  • Australia was close to its present global position.
  • The continental plate carrying Australia had collided with the South East Asian plate.


  • Australia's climate was warm and wet but soon began to dry again.


  • Australia's forests were dominated by gum and wattle trees.
  • A dazzling mixture of wildflowers blossomed in the new open spaces.


  • Many familiar animals such as Agile Wallabies, Saltwater Crocodiles and Budgerigars made their appearance for the first time.
  • Most of the older animals also remained, including deep-headed land crocodiles.
  • In some animal groups, giant species evolved for example, the largest snake that ever lived a 10m long python.
  • New groups of animals were arriving from South East Asia via island chains. Among these were Australia's first rats and mice.

What was happening in the rest of the world

  • A land bridge between North and South America allowed many groups of animals to move back and forth between these continents.
  • Ancestral humans had appeared in the Rift Valley of Kenya, Africa.