Australia’s Thunderbird

By Dr Geoff Hughes, UNE Discovery

Australia is famous for its unique animals, including all of the various marsupials and monotremes. But the emu and cassowary are quite famous as well; giant flightless birds, related to the ostrich and the kiwi. Australia used to have even bigger birds, though, and recent finding by scientists at Flinders University are giving new insights into what these giants looked like.

Known from fossils for more than a century, Genyornis newtoni is a giant bird that weighed as much as five times more than an emu. The species belonged to a group of flightless birds called mihirungs (“giant bird” in Tjapwuring), and are distant cousins of ducks and geese, not emus and cassowaries. They were somewhat close relatives of magpie-geese, but their actual closest living relatives live in South America, a relic of a time when the two continents were connected via Antarctica.

Most fossil finds of these giants are quite limited, with only a damaged skull discovered in 1913 giving us a clue to what its face might have looked like. Most reconstructions of Genyornis beaks looked like a giant version of a magpie-goose, or something like a giant seed-eating finch. But a recent finding by Dr Phoebe McInerney and her team has changed our picture of the species, when they dug up a beautifully-intact skull at Lake Callabonnam in South Australia.

Older reconstruction of Genyornis. Credit: Vita-Brits Prehistoric Beast Cards (date unknown)

Genyornis had a wide head and beak, with a helmet-like casque on top. It appears to have had a much thicker bill than previously thought, and spent a lot of time feeding on aquatic vegetation. This might have been what led to the species’ extinction, actually, as the marshes that they fed in started to dry up or turn salty during the last Ice Age. The new skull fossil was found in an area where a lot of animals died stuck in a mud flat.

New reconstruction based on recent fossil findings. Credit: Jakob Blockland (2024)

Aboriginal humans would have likely seen these magnificent birds in the flesh. They would have lived alongside other prehistoric giants, like the rhino-sized wombat relative Diprotodon, the giant kangaroo Procoptodon, and the huge goanna Megalania (Varanus priscus). The Genyornis‘ temperament isn’t known, but their size would make them formidable animals – something not tangled with lightly!