Game Over Planet Killer

Game Over

Planet Killer

No singular factor can explain the extinction of megafauna across all of Australia and New Guinea. Scientists now look for extinction evidence within each region of the continent. They are looking for evidence of:

  • climate change (e.g., intensifying and longer dry periods reducing drinking water)
  • human hunting (e.g. over-hunting by people reducing population size)
  • fire (e.g. increased burning of the landscape)
  • vegetation change (e.g. reducing plant food for herbivorous megafauna)
  • diseases (e.g. new diseases reducing population size) 

Research, led by Queensland Museum, has focused on the extinction of megafauna from the Fitzroy River basin of central eastern Queensland. Their studies focus on the rich fossil record discovered at Mt. Etna Caves National Park, Capricorn Caves and South Walker Creek Mine.

Extinction 1

280,000-205,000 ya

  • A climate of high year-round rainfall changes to a seasonal dry climate, never to return.
  • Lowland rainforests, that depend on high year-round rainfall, go extinct and take with them the at least 113 rainforest species, including megafauna. 
  • The extinction of rainforest species is immense, including at least 85 mammal, 6 reptile and 22 frog species. Possums suffered greatly with at least 27 species extinct.  
  • Only one megafauna species survives in the rainforests of Australia today, the Southern Cassowary, Casuarius casuarius.

Extinction 2

41,000-36,000 years ago.

  • Climate rapidly dries as rivers slow and permanent waterholes become scarce. 
  • Increased fire along with nutritionally poor and toxic vegetation dominate the landscape.  
  • The combined permanent loss of freshwater and nutritional food makes survival of most herbivorous megafauna impossible.
  • Carnivorous predatory megafauna follow as their prime food source disappears.
  • Most megafauna succumb to these poor conditions, but some survive to the present day.

Surviving Extinction

  • For megafauna herbivores, surviving the extreme and unpredictable conditions of the past required travelling great distances between water sources. The Red Kangaroo and Emu are perfectly adopted to survive.
  • For the surviving megafauna predator, the Saltwater Crocodile, being able to live in freshwater and saltwater environments gave this species the edge over other megafauna reptiles.