Fossil from huge 'terror bird' discovered for the first time in Colombia

The identification of part of the fossilized remains of a so-called "terror bird" species in South America has given researchers new insight into the apex predators that roamed some 12 million years ago.

The bird, discovered in central Colombia nearly two decades ago, was only recently identified as what may be the largest known species of terror bird ever discovered.

Phorusrhacids, as they are known by their scientific name, were meat-eating birds that during the Cenozoic Era were at the top of the food chain. They had slender bodies, huge beaks and could run fast.

"Terror birds lived on the ground, had limbs adapted for running, and mostly ate other animals," Siobhán Cooke, an associate professor of functional anatomy and evolution at the Johns Hopkins University School of Medicine and one of the authors of the research, said in a university release.

New discovery could be the largest terror bird found

The terror bird was identified using part of its left leg bone discovered in a fossil field in the Tatacoa Desert in Colombia. No other parts of its body have been located yet.

The leg bone was found by Cesar Augusto Perdomo, who curates the Museo La Tormenta in Huila, Colombia, nearly 20 years ago, and wasn't identified until last year and further analyzed earlier in 2024.

The researchers said in their findings published Monday in the Papers on Palaeontology journal that unique features about the leg bone suggest the bird is a previously undiscovered species. However, a lack of comparable skeletal fragments from known species available means they could not conclusively determine it to be a new species.

"It's possible there are fossils in existing collections that haven't been recognized yet as terror birds because the bones are less diagnostic than the lower leg bone we found," Cooke said.

The bone "may correspond to the largest terror bird that ever existed," the researchers said.

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Using the leg bone and comparing it to the fossils of other known species of terror birds, they estimated the size of the whole body to be 5% to 20% larger than existing known species, which were between 3 and 9 feet tall. Its weight was approximately 156 kg, or about 343 pounds.

The leg bone also had marks that likely came from the teeth of an extinct crocodilian species, a Purussaurus, which grew up to 30 feet long, Cooke said.

Terror birds were top predators of their time

Terror birds' massive beaks and the way their skulls are shaped tells scientists that they were very good predators. They're known as terror birds because of their killing efficiency, according to Carleton University's Hooper Virtual Natural History Museum.

They likely lived spread out, as opposed to their more populous prey, which could help explain why they haven't been found in Colombia before, the researchers said.

Before this discovery, terror bird fossils were mostly found farther south on the continent, including in Argentina and Uruguay. The oldest terror bird fossils suggested they were alive before the North and South American continents were connected.

Newer terror bird fossils have also been found in southern North America, including in Texas and Florida back in the 1960s.

The new fossil is the first to be discovered so far north in South America, and was found after over 100 years of research at the La Venta badlands, a fossil site in Colombia, the researchers said.

The field in central Colombia where the terror bird fossil was discovered nearly 20 years ago. The fossil was recently identified as a type of Phorusrhacidae, or terror bird, a meat-eating apex predator that lived 12 million years ago.
The field in central Colombia where the terror bird fossil was discovered nearly 20 years ago. The fossil was recently identified as a type of Phorusrhacidae, or terror bird, a meat-eating apex predator that lived 12 million years ago.

The researchers said it sheds new light on what the region looked like millions of years ago and the food chain there. Scientists think the region was humid and full of rivers and other water bodies. The existence of terror birds there suggests a mixed environment, with forested areas, open areas and bodies of water.

The terror birds lived alongside other predators that included meat-eating mammals and crocodilian creatures, the researchers wrote. There were also primates, hoofed mammals, and glyptodonts – huge armored relatives of the modern armadillo that were as big as cars.

"It would have been a fascinating place to walk around and see all of these now extinct animals," Cooke said.

This article originally appeared on USA TODAY: 'Terror bird' fossil discovered, identified in Colombia