The 10-foot-tall carnivorous bird sported a hooked beak, and must have been an alarming sight for other animals. Researchers say that they have now uncovered an almost complete fossil of a new species of terror bird, which has revealed previously unknown details about their anatomy and hearing, writes Laura Geggel for LiveScience.

Scientists Reveal How Prehistoric "Terror Birds" Hunted

New species of terror bird

The fossil was discovered in 2010, on a beach in the beach resort of Mar del Plata, on the east coast of Argentina. Federico Degrange, an assistant researcher of vertebrate paleontology at the Centro de Investigaciones en Ciencias de la Tierra and the Universidad Nacional de Córdoba in Argentina, said that scientists were pleasantly surprised to find that the fossil is the most complete example of a terror bird ever discovered, and over 90% of its bones are preserved.

Researchers have given the new species the name Llallawavis scagliai. “Llallawa” means “magnificent” in the Quechua language, native to the people of the central Andes, and “avis,” is the Latin word for “bird.” The species was named in memory of Galileo Juan Scaglia, a famed Argentine naturalist who passed away in 1989.

The terror bird fossil is the first that has both the trachea and palate completely intact. Even better, the delicate bones of the ears, eye sockets, brain box and skull are also intact, allowing researchers new insight into the sensory capabilities of the flightless bird.

Hunting methods revealed

The inner ear structures suggest that terror birds was especially sensitive to low-frequency sounds such as its prey’s footsteps hitting the ground, and may also have communicated using low-frequencies.

“That actually tells us quite a bit about what the animals do, simply because low-frequency sounds tend to propagate across the environment with little change in volume,” said Lawrence Witmer, a professor of anatomy at Ohio University who was not involved in the study.

Other animals sensitive to low frequencies include the Tyrannosaurus rex, crocodiles, elephants and rhinos, Witmer said.

Research also revealed that the skull was stronger than other species, which could have allowed terror birds to slam its prey with its hooked beak.