There used to be a real horse-sized duck – the Dromornis Stirtoni

Alex .A
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Measuring 3 meters in height and weighing up to 65kg, Dromornis is a genus of prehistoric giant birds.

Dromornis  belonged to Dromornithidae,  a family of giant birds that lived 8 million years ago until less than  30,000 years ago.

Since millions of years by this time, Australia had been separated from the big southern landmass of Gondwana. Typical for animals in Australia is the fact that they had evolved slowly, completely isolated from the animals of the other continents.

 

A fossil (cast) of the extinct Dromornis stirtoni from Australia. Photographed at Dinoday 2009 By Kevmin - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=6657818

A fossil (cast) of the extinct Dromornis stirtoni from Australia. Photographed at Dinoday 2009 By Kevmin – Own work, CC BY-SA 3.0, 

Because of the very poor fossil record of  D. australis (the type species of the genus) and a huge time gap between the  two Dromornis species, D. stirtoni may ultimately be reassigned to the genus of Bullockornis.

Sometimes referred to as  “Stirton’s thunder birds” or Mihirung birds, Dromornis stirtoni  was around 3 meters (9.8 ft) tall and weighed up to 650kg.   With a long neck and stub-like wings, the giant birds were taller then Aepyornis and heavier than the Moa. 

Even though Dromornis stirtoni  had really strong and powerful legs it is not believed to have been a fast runner.

The bird’s beak was large and immensely strong, leading some researchers to hypothesize that it was a herbivore that used its beak to shear through tough plant stalks.  However, others  theories suggest that the bird was a carnivore, due to the size of the bird’s beak.

 

 

 

D. stirtoni, artist's impression By Nobu Tamura (http://spinops.blogspot.com) - Own work, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=19459204

D. stirtoni, artist’s impression Photo Credit

 

 

Holotype femur of D. australis By James Erxleben - http://www.lib.utexas.edu/books/nzbirds/html/txu-oclc-7314815-2-07-p-043.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=12878895

Holotype femur of D. australis
Photo Credit

 

Dromornis was sexually dimorphic. Males were more robust and heavier, though not necessarily taller, than females.It inhabited subtropical open woodlands in Australia during the Late Miocene to the early Pliocene. There were forests and a constant water supply at Alcoota, one area where the Dromornis birds lived, albeit the climate was very changeable.