Science

Giant extinct bird brains reveal "extreme evolutionary experiments"

Giant extinct bird brains reve...
An artist's impression of Dromornis stirtoni, an extinct creature that was one of the largest birds to ever walk the Earth
An artist's impression of Dromornis stirtoni, an extinct creature that was one of the largest birds to ever walk the Earth
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A reconstructed skeleton of Dromornis planei, on display in the Museum of the Northern Territory, Alice Springs, Australia
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A reconstructed skeleton of Dromornis planei, on display in the Museum of the Northern Territory, Alice Springs, Australia
An artist's impression of Dromornis stirtoni, an extinct creature that was one of the largest birds to ever walk the Earth
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An artist's impression of Dromornis stirtoni, an extinct creature that was one of the largest birds to ever walk the Earth
An artist's impression of a species of dromornithid, a family of extinct giant flightless birds that walked Australia for millions of years
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An artist's impression of a species of dromornithid, a family of extinct giant flightless birds that walked Australia for millions of years
3D models of the brains of the ancient birds, compared to living relatives
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3D models of the brains of the ancient birds, compared to living relatives
Warren Handley and Trevor Worthy, authors of the new study, hold up the fossil skull and upper bill of a Dromornis planei
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Warren Handley and Trevor Worthy, authors of the new study, hold up the fossil skull and upper bill of a Dromornis planei
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Australian scientists have studied the biggest bird-brains in history for the first time. Paleontologists examined the brain cases of extinct flightless birds in the dromornithidae family – including some of the largest birds that ever existed – and found that they represented some weird evolutionary experiments.

Dromornithidae were a group of gigantic flightless birds that lived in Australia from the Late Oligocene, around 25 million years ago, until they went extinct as recently as 50,000 years ago, during the Pleistocene. They’re also known as mihirungs – an Aboriginal word for “giant bird” – or if you want to get a bit more colorful, “demon ducks” or “thunder birds.” The largest species could grow up to 3 m (9.8 ft) tall and weigh about 600 kg (1,320 lb).

A reconstructed skeleton of Dromornis planei, on display in the Museum of the Northern Territory, Alice Springs, Australia
A reconstructed skeleton of Dromornis planei, on display in the Museum of the Northern Territory, Alice Springs, Australia

The team focused on fossil skulls from four species of mihirungs that lived across that time range: Dromornis murrayi, which lived about 24 million years ago; Dromornis planei and Dromornis Ilbandornis, which both lived around 12 million years ago; and Dromornis stirtoni, from around 7 million years ago.

They made CT scans of the brain cases of these ancient birds, then created 3D models of them and compared them to similar (albeit smaller) modern relatives. Doing so revealed the size and shape of the brains, which most closely resembles that of the modern chicken. From this the scientists are able to recreate their biology and lifestyle.

“Together with their large, forward-facing eyes and very large bills, the shape of their brains and nerves suggested these birds likely had well-developed stereoscopic vision, or depth perception, and fed on a diet of soft leaves and fruit,” says Dr Warren Handley, lead author of the study.

An artist's impression of a species of dromornithid, a family of extinct giant flightless birds that walked Australia for millions of years
An artist's impression of a species of dromornithid, a family of extinct giant flightless birds that walked Australia for millions of years

The most recent species, Dromornis stirtoni, was particularly fascinating. The second-largest known bird to have ever lived, it sported a weird-shaped head that, the team says, would have led to an equally bizarre brain shape.

“This bird had the largest skull but behind the massive bill was a weird cranium,” says Trevor Worthy, senior author of the study. “To accommodate the muscles to wield this massive bill, the cranium had become taller and wider than it was long, and so the brain within was squeezed and flattened to fit. It would appear these giant birds were probably what evolution produced when it gave chickens free rein in Australian environmental conditions.”

The research was published in the journal Diversity.

Source: Flinders University via Scimex

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12 comments
12 comments
paul314
What's the difference between a flightless bird and a feathered dinosaur?
Username
@paul314 - One is a reptile.
Pierre Collet
@paul314: 40 million years?
Nelson Hyde Chick
Username, Dinosaurs being reptiles is no longer the scientific consensus: https://www.activewild.com/are-dinosaurs-reptiles/

Reptiles are classified as being cold blooded, and there is no way T-Rex was cold blooded.
Robert Baden
Nelson Hyde Chick

Reptiles are an incomplete group then, since dinosaurs and birds are their descendants. I do see birds being considered reptiles in a lot of places.
Signguy
Another attempt to thwart Creation.
ash
ummm... "experiment" is anthropomorphism
toni24
Hmmm, died out about 50,000 years ago about the same time Australia Aborigines arrived in numbers in Australia. Which, due to the fact that the Aborigines actually have a name for these creatures, probably is why they went extinct. "Tastes like Chicken"
Adrian Garcia
Answering the "Paul314":

Actually, birds are dinosaurs. They're included in the same phylogenetic taxonomy, so they still being dinosaurs and you probably eat dinosaur as lunch (we call it chicken).
Username
@Nelson Hyde Chick T-rex didn't have feathers for one thing. That some dinosaurs are no longer classified as reptiles doesn't mean none of them are.