Learning about the massive South American "terror bird"

From the size and shape of the beak, researchers have always known that the massive South American "terror bird" was a predator. Now they know precisely how the bird killed — wielding its huge skull and hooked beak like an pickax and repeatedly chopping at prey until it succumbed.

The 5-foot-tall, 90-pound Andalgalornis steulleti, whose skull was nearly twice the size of a human's, went extinct millions of years ago, but Argentine and U.S. researchers have been using CT scans and biomechanical reconstructions to deduce how the flightless predators killed. Their findings were announced Wednesday.