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2007-07-03, 17:24:18 If you're terrified of birds, this post might give you nightmares.
The biggest bird that ever prowled the skies, a gigantic condor-like creature known as Argentavis, had a sprawling wingspan of more than 6 meters (21 feet). But a new study of the bird's aerodynamics suggest it was so big it was barely able to fly. National Geographic News reports : Despite its massive flight muscles and 21-foot (6.4-meter) wingspan, the giant bird probably could not generate enough lift to take off from a level surface, according to a new study. Like human hang gliders, Argentavis probably had to run downhill into a headwind to become airborne, said Sankar Chatterjee of Texas Tech University in Lubbock. "Takeoff capability is the limiting factor for the size of flying birds, and Argentavis almost reached the upper limit," Chatterjee said. "Heavier birds such as the ostrich had to give up flight." Once aloft, however, Arentavis was no ostrich. Despite weighing as much as 16 bald eagles, Chatterjee said, "it was an excellent glider, like a sail plane."
I imagine it had to eat a lot of prey to keep itself alive, and flapping around. So what would it eat? Chatterjee and co-author Kenneth Campbell, of the Natural History Museum of Los Angeles County, say fossil details indicate the species was an active predator. "[The birds' skull] was adapted for catching prey and swallowing it whole," Campbell said. "Its jaw mechanics were not suited for tearing flesh from carcasses, as in vultures, nor for tearing prey animals apart for swallowing, as in eagles and owls." (Read related story: "Terror Birds: Predators With a Kung Fu Kick?" [August 1, 2005].)
But another researcher thinks this bird couldn't fly enough to swoop down and grab its prey, so it must have scavenged from carcasses. Maybe it's not as scary as it seems at first.
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