4 July 2007


Landing teratorn Argentiavis from Chatterjee et al. (2007).

I‘m not sure exactly what the appropriate response is when you have a 70 kilo bird descending on you at 6 meters per second, but I’m pretty sure throwing up your hands and adopting a shocked expression isn’t going to cut it.

Paleo figures are loaded with hidden gems like this, both intentional and unintentional. This one comes from a new PNAS paper by Chatterjee, Templin and Campbell entitled, The aerodynamics of Argentavis, the world’s largest flying bird from the Miocene of Argentina.

The authors use biomechanical modeling to conclude, perhaps unsurprisingly, that Argentavis wouldn’t have been able to loft it’s 150lb bulk into the air with wing power alone, and would have probably needed a good running start, as seen in living albatrosses in this video clip. Once airborne, these absurdly large birds would have been master soarers, using thermals and slope winds to careen through the air at an speeds of 30 mph as they searched for prey.

Getting aloft is surely an awkward proposition when you are a 150 lb bird, but that’s the easy part. Coming down safely is a matter of life and death. The figure at top shows an Argentavis coming down at the literal break-neck speed of 6 m/s, so in this picture both the hapless human scale and the monster bird are, technically speaking, royally effed.

To get down safely, the authors suggest that the giant birds would have exploited head-winds to slow their hulking frames down below the 5 m/s fatal impact speed. Snap!

Death Throes pt. II is on it’s way, really, with help from Werner Herzog, Edward Gorey, and Arc’Teryx.

One Response to “!”

  1. […] PNAS paper focusing on Argentavis in World’s Largest Bird Was a Glider. You should check out Neil’s take on the paper over at microecos, […]

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