Researchers from U. S and Argentina are reported to have posted their findings on the massive South American "terror bird" that went extinct millions of years ago.

The 5-foot-tall, 90-pound Andalgalornis steulleti, had a skull size nearly double the size of a human skull.

The study was conducted in a bid to deduce as how the flightless bird killed its prey. However, the bird was known to be a predator, but the actual technique was not known.

The study findings have been reached with the help of CT scans and biomechanical reconstructions, the researchers claimed.

They study findings published their results in the online journal PLoS One on Wednesday. The research has claimed that the birds used its huge beaks that were capable of extending swift and powerful pecks making repeated attacks that actually killed its prey prior to digging into the prey's body flesh.

Dr Wroe, a researcher from the University of Sydney, Australia, who was also a part of an international team into the investigation over the powerful predator and its predatory behavior, quoted, "These birds had enormous beaks with big hooks on the end. But we've shown they had to use those beaks with some precision and caution".