Argentavis

argentavis
Argentavis. Wikimedia Commons

Name:

Argentavis (Greek for "Argentina bird"); pronounced ARE-jen-TAY-viss

Habitat:

Skies of South America

Historical Epoch:

Late Miocene (6 million years ago)

Size and Weight:

23-foot wingspan and up to 200 pounds

Diet:

Meat

Distinguishing Characteristics:

Enormous wingspan; long legs and feet

 

About Argentavis

Just how big was Argentavis? To put things in perspective, one of the largest flying birds alive today is the Andean Condor, which has a wingspan of nine feet and weighs about 25 pounds.

By comparison, the wingspan of Argentavis was comparable to that of a small plane--close to 25 feet from tip to tip--and it weighed anywhere between 150 and 250 pounds. By these tokens, Argentavis is best compared not to other prehistoric birds, which tended to be much more modestly scaled, but to the huge pterosaurs that preceded it by 60 million years, notably the giant Quetzalcoatlus (which had a wingspan of up to 35 feet).

Given its enormous size, you might assume that Argentavis was the "top bird" of Miocene South America, about six million years ago. However, at this time, "terror birds" were still thick on the ground, including descendants of the slightly earlier Phorusrhacos and Kelenken. These flightless birds were built like meat-eating dinosaurs, complete with long legs, grasping hands, and sharp beaks that they wielded on their prey like hatchets. Argentavis probably kept a wary distance from these terror birds (and vice-versa), but it may well have raided their hard-won kill from above, like some kind of oversized flying hyena.

A flying animal the size of Argentavis presents some difficult issues, chief of which is how this prehistoric bird managed to a) launch itself off the ground and b) keep itself in the air once launched. It's now believed that Argentavis took off and flew like a pterosaur, unfurling its wings (but only rarely flapping them) in order to catch the high-altitude air currents above its South American habitat.

It's still unknown if Argentavis was an active predator of the huge mammals of late Miocene South America, or if, like a vulture, it contented itself with scavenging already-dead corpses; all we can say for sure is that it was definitely not a pelagic (sea-flying) bird like modern seagulls, since its fossils were discovered in the interior of Argentina.

As with its style of flight, paleontologists have made a lot of educated guesses about Argentavis, most of which, unfortunately, are not supported by direct fossil evidence. For example, analogy with similarly built modern birds suggests that Argentavis laid very few eggs (perhaps an average of only one or two per year), which were carefully brooded by both parents, and presumably not subject to frequent predation by hungry mammals. Hatchlings probably left the nest after about 16 months, and were only fully grown by the age of 10 or 12; most controversially, some naturalists have suggested that Argentavis could attain a maximum age of 100 years, about the same as modern (and much smaller) parrots, which are already among the longest-lived vertebrates on earth.

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Strauss, Bob. "Argentavis." ThoughtCo, Jun. 21, 2017, thoughtco.com/overview-of-argentavis-1093574. Strauss, Bob. (2017, June 21). Argentavis. Retrieved from https://www.thoughtco.com/overview-of-argentavis-1093574 Strauss, Bob. "Argentavis." ThoughtCo. https://www.thoughtco.com/overview-of-argentavis-1093574 (accessed May 26, 2018).