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Dromornis

life science Maturity 7-9 Next article →

Dromornis is a genus of enormous, flightless prehistoric birds from Australia. These birds belonged to a family called Dromornithidae, which are commonly known as mihirungs. The name "mihirung" comes from an Aboriginal word used by the Tjapwuring people of Western Victoria, meaning "giant bird."

Dromornis stirtoni
Dromornis stirtoni

Although they might look like modern emus, they are actually more closely related to the earliest waterfowl, such as ducks and geese. This group of birds lived in Australia from the Oligocene epoch until the Pliocene epoch. They represent a fascinating lineage of ground-dwelling animals that evolved to be massive.

Anserimorphs size comparison
Anserimorphs size comparison

To understand how these birds lived, we can look at their physical structure. Because they were flightless, their wings were greatly reduced. These small wings would have been hidden beneath their thick plumage. Instead of flying, they relied on large, powerful legs to move across the land. Most scientists believe they were herbivorous browsers. This means they likely spent their time eating various types of vegetation. Some species may have even been aggressive when defending their territory.

Dromornis BW
Dromornis BW

The Dromornis lineage shows a pattern of changing over millions of years. Scientists propose a succession of species that generally increased in size over time. The lineage includes species such as Dromornis murrayi, Dromornis planei, Dromornis stirtoni, and Dromornis australis. Comparative studies of their skull structures suggest their heads and bills became shorter over time. This process is known as being foreshortened. This evolutionary path shows how a single group of animals can adapt and grow larger through different geological eras.

Our knowledge of these birds began with the work of Richard Owen. In 1872, Owen described the first species, Dromornis australis. He found a fossilized femur, which is a thigh bone, at a site called Peak Downs in Queensland. This bone was discovered deep in a well shaft. It sat beneath 30 feet of alluvial soil and 150 feet of pebbles and boulders.

The bone was so filled with minerals like iron pyrites that it looked almost like a reptile bone. Owen had seen other bones earlier, but he waited many years before publishing his findings.

Dromornis australis pl 32 1874
Dromornis australis pl 32 1874

Different species lived in different environments and at different times. Dromornis murrayi lived about 26 million years ago during the Oligocene and early Miocene. It was the smallest member of the genus and lived in the Riversleigh area of Queensland. Its skull held an exceptionally small brain.

Dromornis stirtoni
Dromornis stirtoni

Another species, Dromornis planei, lived about 15 million years ago in the Middle Miocene. It was found in the Bullock Creek fauna of the Northern Territory. This bird had a stocky build and lived near seasonal wetlands and rivers.

Bullockornis
Bullockornis

Some members of this genus reached truly incredible sizes. Dromornis stirtoni is one of the largest known birds to ever exist. It is often called "Stirton's thunderbird." While it was massive, it may not have been the heaviest bird ever. The extinct elephant bird, Aepyornis maximus, from Madagascar, was likely just as heavy or even heavier. The height of Dromornis stirtoni might have even exceeded the females of the giant moa, a different extinct bird from New Zealand.

Anserimorphs size comparison
Anserimorphs size comparison

The study of Dromornis connects many different areas of science. It links paleontology, the study of fossils, with evolutionary biology. By studying the bones of these "demon ducks," scientists can learn about the ancient environments of Australia. They can see how animals changed from smaller ancestors into giants. This helps us understand how life adapts to different climates and available food sources over millions of years.

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🖼️ Images & Media (6)
File:Dromornis stirtoni.jpg
Dromornis stirtoni.jpg
File:Anserimorphs size comparison.png
Anserimorphs size comparison.png
File:Dromosaurus australis pl 33 1874.png
Dromosaurus australis pl 33 1874.png
File:Dromornis australis pl 32 1874.png
Dromornis australis pl 32 1874.png
File:Bullockornis.jpg
Bullockornis.jpg
File:Dromornis BW.jpg
Dromornis BW.jpg
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