World's largest dinosaur footprint site identified in Bolivia
by Mar Puig · UPIDec. 16 (UPI) -- More than 16,600 footprints left by carnivorous dinosaurs of different sizes that walked, ran and even swam about 66 million years ago have been identified at the Carreras Pampa site inside Torotoro National Park in central Bolivia, making the country home to the world's largest known concentration of theropod tracks.
Theropods, a dinosaur subgroup, walked on two legs, and typically had hollow, thin-walled bones, short forelimbs and strong hind legs.
The findings were published in the peer-reviewed scientific journal PLOS One and are based on six years of fieldwork carried out by an international team of researchers.
"The study of this gigantic dinosaur track site is highly significant for several reasons. It is the largest known site to date and far exceeds other similar sites in the number of preserved footprints," Spanish paleontologist Raúl Esperante, the study's lead author, told Argentine outlet Infobae.
Researchers documented 1,321 theropod trackways along with hundreds of isolated footprints, tail drag marks and 1,378 swimming traces. All the tracks are concentrated in nine connected sectors on a single fossil surface that cover about 80,730 square feet, an area comparable to a soccer field.
The footprints belong to bipedal carnivorous dinosaurs and display a wide range of sizes. Some were left by animals up to 33 feet long, while others correspond to very small specimens measuring just 12 inches in height, roughly the size of a modern chicken.
According to the researchers, this diversity indicates the area was used by different types of dinosaurs rather than a single species.
The team concluded that Carreras Pampa was not a permanent settlement area, but rather a frequently used passageway. The orientation of the trackways shows a clear pattern in two directions, suggesting repeated movement along the shoreline of an ancient freshwater lake.
That natural route likely functioned as a kind of prehistoric highway linking regions of what is now southern Peru with northwestern Argentina, the researchers said.
Unlike bone fossils, which are scarce in the region, footprints allow scientists to reconstruct everyday behavior. From the tracks, researchers were able to estimate walking speeds, pauses, changes in direction and even swimming attempts.
In several areas, scientists identified footprints left as dinosaurs moved through shallow water, scraping the muddy bottom before rising water levels sealed and preserved the marks.
"The preservation of many of the footprints is excellent and the number recorded is unprecedented," said Richard Butler, a paleontologist at the University of Birmingham in England and a co-author of the study. He said the site offers an exceptional opportunity to understand how dinosaurs moved and behaved shortly before their extinction.
The study also documented primitive bird footprints associated with the dinosaur tracks, as well as other signs of biological activity, reinforcing the idea that the area once supported an active and diverse ecosystem.
Bolivia is already internationally known for the Cal Orck'o site near the city of Sucre, which preserves about 12,000 dinosaur footprints on a near-vertical rock wall. With Carreras Pampa, the country adds another world record and strengthens its position as a key location for the study of fossilized dinosaur tracks.
Researchers said fieldwork will continue and that many more footprints could be uncovered in surrounding areas, potentially expanding even further this unique record of South America's prehistoric past.