The place is called Giant’s Path, and it’s no coincidence. Remains of local megafauna had already been found in a stream near the city of Canelones, just 45 minutes from Montevideo. Now, an unexpected fossil confirms that the name holds more truth than anyone imagined.
A bone fragment led Uruguayan paleontologists to reconstruct the existence of a colossal vulture, larger than the Andean condor — today the most impressive flying bird in the Americas — which would have soared through the skies of southern Pleistocene South America. According to the researchers, this bird could have belonged to a previously unknown lineage of South American cathartids.
The discovery, recently published in the journal Historical Biology, offers an unexpected glimpse into the Ice Age in the Americas. It reveals a bird large enough to feed on glyptodonts and mastodons, and a powerful glider capable of long-distance travel in search of carrion.
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Two Families of Vultures
The study’s lead authors, paleontologists Washington Jones and Andrés Rinderknecht of the National Museum of Natural History, note that this “unexpectedly large” bird bore similarities to the modern California condor (Gymnogyps californianus), which belongs to the same lineage as the Andean condor (Vultur gryphus), and to the somewhat smaller King Vulture (Sarcoramphus papa). They also describe certain morphological similarities with smaller vultures, such as the red-headed and black-headed vultures.
To put this in context, the common term “vulture” groups two types of birds with similar scavenging habits that are not directly related. On one hand, the “Old World vultures,” native to Africa and Asia, belong to two distinct lineages: the Gypaetines and the Aegypinidae, which are part of the Accipitridae family, along with eagles and harriers. On the other hand, the “New World vultures,” which include condors and American vultures, belong to the family Cathartidae, a group of birds unique to the Americas.
“It’s the size of the largest condors, but the bone we found — a tarsometatarsus — has a very flattened shape, indicating that it was much more similar to local vultures, especially the red-headed vulture. That’s the surprise,” says Jones.
Imagine it this way: this giant vulture would be slightly larger than the Andean condor, the world’s largest flying bird, whose wingspan can reach about 10 feet (3 meters), and be more than six times larger than a red-headed vulture. Its mere presence in the Pleistocene skies, some 13,000 years ago, would have been as imposing and intimidating as the giant mammals roaming the land beneath it.
Comparing Vulture Bones
Comparison of fossils with several red-headed vulture tarsometatarsi.
(Image Courtesy of Washington Jones)
The bone that allowed this giant bird to be identified is a tarsometatarsus, a structure that might seem unusual at first glance. In birds, several ankle and foot bones fuse into a single elongated element, forming what would be the “lower part” of the leg, just above the toes. Unlike humans — who have a tibia, fibula, and then a foot — birds have three main segments: the femur, the tibiotarsus, and the tarsometatarsus.
The latter supports the toes and acts as a lever for walking, perching, or grasping prey, and its shape reveals key details about the animal’s size and posture. Although the fragment — about 1.6 inches long — is broken, paleontologists were able to identify tendon insertion marks and articular facets that would have connected to the toes, providing enough clues to reconstruct the bird’s size.
In comparison, the tarsometatarsus of a California or Andean condor is much more rounded; the Uruguayan fossil is similar in size but noticeably more flattened, more akin to vultures of the genus Cathartes, particularly the red-headed vulture, although much larger.
However, Rinderknecht compared the fossil with the tarsometatarsi of California condors at the Smithsonian Institution’s National Museum of Natural History and found that some also exhibited flattened bones and certain features similar to those of the Uruguayan specimen and the red-headed vulture. This suggests two possibilities: that the Uruguayan specimen represents a new taxon of a large cathartid with affinities to the California condor, or a new taxon of a large cathartid related to Cathartes.
“What we propose is that our giant vulture could represent a new lineage, that is, a previously unknown evolutionary line within American vultures,” explains Jones.
A Complex Fossil Region
Lacking additional bones, Jones and Rinderknecht were hesitant to assign a formal name, but they say they are convinced it represents a new form.
This caution is also due to the fact that across the Americas, other bone fragments — not tarsometatarsi — have not been matched to any known species, creating uncertainty about the true diversity of these vultures. In this context, Argentine paleontologist Marcos Cenizo, a specialist in bird evolution, notes that although the specimens found in Uruguay are fragmentary, all evidence suggests they are not related to the Andean condor.
He also cautions that many of the species reported for the South American Pleistocene may be overestimated, as they are based on incomplete remains. The restraint shown by the Uruguayan researchers in not naming this species reflects, according to Cenizo, responsible scientific practice in light of the region’s complex fossil record.
The disappearance of this giant vulture was likely closely linked to the extinction of megafauna at the end of the Pleistocene. The arrival of humans, whose hunting and landscape modifications affected mastodons, giant sloths, glyptodonts, and toxodonts, among others, also impacted their scavengers.
Cenizo points out that, similar to modern ecosystems in Africa and Asia — where the presence of megamammals coincides with a notable diversity of large vultures — it is reasonable to infer that this giant South American vulture vanished once its food sources disappeared.
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