You wouldn’t want to run afoul of this feathery giant.
Scientists poring over bird bones estimate that an extinct Australian species weighed 1,000 pounds on average. That’s as much as a mid-sized moose – and substantial enough to make this bird the biggest that ever lived, outstripping even the prehistoric elephant bird of Madagascar.
The data also hints the Australian Big Bird, properly termed Dromornis stirtoni, fiercely defended its young, much as Canada geese do today. And though the Aussie Big Bird was flightless and a vegetarian, a close inspection of its nest would’ve been a mistake.
A 1,000-pound male “would’ve been extremely dangerous to you if you approached him and his territory and his chicks,” says study co-author Warren Handley, a researcher at Australia’s Flinders University. “They were massive, gigantic birds. You would’ve felt the Earth shake when one came past you.”
Handley measured dozens of Dromornis fossils, all roughly 8 million years old and unearthed near an ancient lake. From those bones the researchers estimate that the biggest of the Big Birds, if it stepped on a scale, would set the needle quivering around 1,300 pounds. Males slightly outweighed females, but both sexes stood nearly 10 feet tall, Handley says.
Big Bird’s rival for bulk is the extinct elephant bird, long billed as the largest fowl on the planet. But the elephant bird, which like Dromornis was flightless, weighed an estimated 800 pounds on average, the researchers report in the Journal of Vertebrate Paleontology. That’s 200 pounds less than the average for Dromornis.
Though hulking, the Aussie Big Bird seems to have been a romantic. Couples likely formed long-lasting bonds, cemented with elaborate greetings to each other, researchers say. They believe Dromornis followed the same pattern as its relatives, today’s ducks and geese: where the males of a species are slightly bigger than females, pairs tend to act lovey-dovey and parents defend babies to the death.
“This would’ve been a formidable creature,” says Geoffery
Birchard of George Mason University, who thinks the study makes a decent case for the Aussie Big Bird as featherweight champion. But he says fossils of these ancient species are too rare for certainty.
Another scientist is unconvinced by the study’s arguments about Dromornis’s love life. The fossils described in the new study may actually belong to several different species, which would make it difficult to compare male and female sizes, says Richard Holdaway of Palaecol Research in New Zealand.
Handley agrees that more fossils of the elephant bird would be helpful, but he notes his estimate of Big Bird’s weight, at least, is based on a generous sample of nearly 50 bones. He also stands behind his finding that males were more massive, though not taller, than females. Scrutiny of the fossils, he says, confirms they belong to only one species.
As to where a Dromornis guy carried his extra weight, many females of Homo sapiens can sympathize. The male Big Bird’s additional heft, researchers found, was mostly in one place: his hips.
