Enormous wings hardly need to be flapped to fly in great circles over the great plains that stretch out under the Andes. A foolproof sight identifies prey that has just emerged from its burrow. Argentavis magnificens drops from the skies to the surface. It catches its victim with its strong claws, with its weight it suffocates any attempt to escape and with its powerful beak it deals a definitive blow. One of the greatest predators of the American past then prepares to eat.
The largest flying bird of all time
Its name means “magnificent Argentine bird” and defines in three words the most outstanding features of this species. Argentavis magnificens lived during the Upper Miocene, between 8 and 6 million years ago , in the current Argentine Pampas and the Patagonia area. Of course it was magnificent, because its dimensions place it among the largest birds in history.
It was a mix between an eagle and a vulture that weighed around 70 kilos , was between 1.5 and 2 meters tall, had a length from beak to tail of 3.5 meters and a wingspan with its wings open that could reach 7 meters . . This makes it the largest known flying bird, rivaling Pelagornis sandersi .
It belongs to the teratornithid family (Teratornithidae), the “monstrous birds”, due to their large size, specialists in gliding using air currents to find their prey. That is why Argentavis is considered a species related to the ancestors of today’s American vultures. Marcos Cenizo, from the Félix de Azara Natural History Foundation, said that:
“It is believed that the teratornithids originated in South America, since their oldest remains were found in deposits with ages between 25 and 5 million years, in Brazil and Argentina. After this time period, teratorns disappear from the South American fossil record, but become remarkably abundant and diverse in North America until their extinction at the end of the Pleistocene, some 12,000 years ago.”
predator and scavenger
Due to its morphology and classification as a species, researchers understand that Argentavis fed both by hunting its prey and by devouring carrion . Small mammals could have been the basis of its diet, but given its size and corpulence, it is not ruled out that it could attack the marsupials of the time and other medium-sized animals.
There are different hypotheses about the use of its beak. Some find it more similar to that of eagles, so Argentavis would feed by swallowing its prey in one bite . Others think that, being a scavenger, it must have had a beak capable of tearing meat easily.
An Argentine giant
In the 1970s, Argentine paleontologists Rosendo Pascual and Eduardo Tonni were looking for fossils in La Pampa. In 1979 they found some fragmented remains of what looked like the bones of a bird, but its size was so huge that they doubted they were right about the fossil.
Later it was confirmed that, indeed, they had found the remains of the largest bird that had flown over those territories of the American South. In 1980, Kenneth E. Campbell and Eduardo Tonni published the scientific description of the species.
Too big to fly?
The size of this giant bird called into question everything that was previously known about flight and aerodynamics. Argentavis exceeded suspected limits for size in birds with the ability to fly . The analysis of the fossils to try to find out the characteristics of its locomotion showed that this animal would be agile on the ground and that it could even trot to stalk its prey or other predators to snatch their prey. But, of course, his specialty was gliding .
It was not a very fast bird, it had an average speed of about 70 kilometers per hour. Specialists believe that they had a method of flight just like the current condors and vultures. That is to say, it could not take off from a static position, nor stay in the air by the force of its flapping wings, but rather it would jump from high slopes or cliffs and take advantage of the constant regime of winds that existed in its habitat to glide for kilometers without hardly beating. His wings.
References:
Campbell, K. and Tonni, E. 1983. Size and Locomotion in Teratorns (Aves: Teratornithidae). The Auk 100, 2, 390-403. DOI: 10.1093/auk/100.2.390.
Chatterjee, S. et al. 2007. The aerodynamics of Argentavis, the world’s largest flying bird from the Miocene of Argentina. PNAS 104, 30, 12398-12403. DOI: 10.1073/pnas.070204010.
