Like the heavyweight champ, this bird could float like a butterfly and sting like a bee.

THE GIST

Analysis of a terror bird's predatory behavior reveals this animal knew how to fight.

At least one of these now-extinct, large birds, Andalgalornis, fought like boxer Muhammad Ali.

Like Ali, they believe the bird was an agile and fast fighter that employed an "attack-and-retreat" strategy.

At 90 pounds, the ancient terror bird Andalgalornis may not have been comparable to a human heavyweight. However, its beak jabs and fleet-footedness were reminiscent of boxer Muhammad Ali's fighting strategy, according to new research.

The study, published in the latest PLoS ONE journal, presents the first detailed look at the predatory style of terror birds, now-extinct flightless birds known for their unusually large, fearsome heads and imposing sizes. At 4.5 feet tall, Andalgalornis was just a "mid-sized" terror bird..

CT scans revealed this bird's skull was strong and rigid in the vertical and fore-aft directions, but was relatively weak from side to side.

"That side-to-side weakness meant that the bird couldn't grapple with struggling prey like a Joe Frazier kind of slugger without risking fracturing the beak. But the great vertical strength of the beak, coupled with the animal's evident agility and speed, suggest that it fought more like Muhammad Ali," co-author Lawrence Witmer told Discovery News.

Witmer, a professor of paleontology and anatomy at Ohio University College of Osteopathic Medicine, further explained that the carnivorous bird used "an attack-and-retreat strategy, repeatedly jabbing straight down with that hatchet-like beak, using carefully placed surgical strikes when openings arose."

Witmer and his team provided the terror bird CT scans to Stephen Wroe, director of the Computational Biomechanics Research Group at the University of New South Wales, Australia.

Wroe assembled 3D engineering models of the terror bird and two living species for comparison: an eagle and the terror bird's closest living relative, the seriema. These two modern birds also had their bite forces measured by other researchers involved in the international project.

"Combining all of this information, we discovered that the bite force of Andalgalornis was a little lower than we expected and weaker than the bite of many carnivorous mammals of about the same size," said lead author Federico Degrange of Argentina's National University of La Plata.

Andalgalornis may have compensated for this weaker bite by using its powerful neck muscles to drive its strong skull into prey like an axe," he added..

Terror birds evolved 60 million years ago in South America, which was an island continent until around 3 million years ago. Shortly after that time, all terror birds mysteriously disappeared from the face of the Earth.

"During the terror bird heyday, "South America was home to a truly weird and wonderful range of unique creatures, from gigantic ground sloths and tank-like glyptodonts (relatives of the armadillo) to strange horse-like liptoterns," Wroe told Discovery News..

The marsupial sabertooth could have been one of the terror bird's chief rivals, but the bird's Muhammad Ali moves may have given it a fighting edge.

"Now that would be something to see: a saber-toothed marsupial (Thylacosmilus) versus a terror bird!" Witmer said. "Thylacosmilus was a more powerful animal, but the terror bird was swifter and more agile. I would say that both were at the top of the food chain."

Terror bird expert Bob Chandler, a professor in the Department of Biological and Environmental Sciences at Georgia College and State University, believes the new study represents "cutting-edge paleontology going beyond the descriptive stage of alpha taxonomy to building sound biomechanical hypotheses based on data only recently made available to researchers by CT scans."

"The authors' insights into the function of the bill of terror birds will help to clarify our understanding of these dynamic and extraordinary terrestrial avian predators," Chandler told Discovery News.

In the future, the researchers additionally hope to better understand how a bird could rise to the top of an ecosystem's food chain, only to later topple down to become extinct.