Imagine a bird so big and powerful that it could snatch a kangaroo from the ground and fly away with it.

Such a bird once existed in Australia, and its fossils have been found in the limestone caves of South Australia.

This is the story of Dynatoaetus gaffae, Australia's largest eagle, and what it reveals about the ancient megafauna that once roamed the continent.

How researchers discovered Australia's largest eagle
A wedge-tailed eagle or eaglehawk (Aquil
(Photo : TORSTEN BLACKWOOD/AFP via Getty Images)

A bird of prey that flew over South Australia's Flinders Ranges 60,000 years ago was Australia's biggest eagle, researchers have confirmed.

The eagle, called Dynatoaetus gaffae, had a wingspan of three meters and 30-centimetre talons powerful enough to grab a small kangaroo.

The first remains of the predator, which was about twice the size of a wedge-tailed eagle, were unearthed in 1956, according to Flinders University paleontologist Ellen Mather.

More fossils were discovered in Mairs Cave and the Naracoorte Caves in 1969, which led Dr Mather and other researchers to revisit the caves two years ago.

They had all the bones of the skeleton to figure out what it was, Dr Mather said. She added that the Dynatoaetus was comparable to the Philippines eagle and the Harpy eagle from South America.

She also said that it was related to the Old World vultures and it did not have any living descendants in Australia today.

Dr Mather and her team's findings were published in the Journal of Ornithology this week.

Also Read: Soaring High: A Philippine Eagle, One of the World's Most Endangered Bird, Released in the Wild

What the giant eagle reveals about Australia's ancient megafauna

Dr Mather said the fossils in the Flinders Rangers told researchers a lot about how the bird lived and what it ate.

She explained that it had quite large and robust leg bones, which indicated that it was a predator specializing in larger prey.

She said that it had strong legs to be able to grab onto and take down a struggling animal. She estimated that it could grab onto a kangaroo and sink its claws in until it stopped struggling.

Associate professor Trevor Worthy said the raptor was almost as big as Haast's eagle, which was the largest ever discovered.

He described how it had giant talons, spreading up to 30cm, which easily would have been able to dispatch a juvenile giant kangaroo, large flightless bird, or other species of lost megafauna from that era.

One of the possible prey items for the giant eagle was Genyornis newtoni, the last of the large, flightless mihirungs ('thunder birds') endemic to Australia.

It was a heavily built bird over 2 meters tall, with tiny wings and massive hind legs.

Fossils of G. newtoni have been found in association with human artifacts, including cave paintings and carved footprints, and Genyornis must have coexisted with the first humans in Australia.

The giant eagle and the thunderbird are just two examples of the diverse and unique megafauna that once roamed Australia before they went extinct due to climate change, human hunting, or other factors.

By studying their fossils, researchers hope to learn more about their ecology, evolution, and interactions with each other and with humans.

Like the mythical phoenix, these ancient creatures rise again from the limestone caves, revealing their secrets to the curious eyes of science.

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