Bold claim: a vast trove of dinosaur footprints and swim traces has been uncovered in South America, reshaping what we know about ancient coastlines and dinosaur movement. Tens of thousands of tracks reveal a detailed snapshot of how different species traveled along an ancient shoreline. A team reports nearly 18,000 impressions at the Carreras Pampa track site, along Bolivian coastlines now buried under time. The site lies within Torotoro National Park in central Bolivia, and findings were shared in a PLOS One paper published midweek.
The tracks stretch in a northwest–southeast pattern, a clue researchers say points to the direction of movement for dinosaurs and other creatures as they traversed the paleocoast. The majority of footprints belong to theropods—bipedal carnivores from the Cretaceous period that include famous predators like Tyrannosaurus rex—though some preserved marks are attributed to birds as well.
Carreras Pampa covers roughly 80,570 square feet and holds the most intact dinosaur footprints and the greatest number of swimming trackways ever found in one place, according to the study. It also records the highest continuity of preserved swim trackways yet documented.
The abundance of traces offers a dynamic view: dinosaurs were walking, running, swimming, and even displaying tail-dragging or sharp turning during their journeys. The swimming tracks likely formed when theropods dragged a midfoot toe along the bottom of shallow water, producing grooves that range from straight to curved, sometimes resembling a comma shape.
Researchers analyzed more than 1,275 trackways, painstakingly clearing debris and sediment to reveal additional impressions.
Unlike many sites that preserve isolated swim tracks, Carreras Pampa features sequences where tracks alternate between the right and left feet, painting a more complete picture of locomotion.
The variety of track shapes and sizes indicates multiple dinosaur types used this ancient shoreline as a kind of prehistoric highway. Some footprints are unusually small—under 4 inches—and researchers theorize they belong to smaller theropods like Coelophysis or to juveniles of larger species.
Mid-size theropods—think animals akin to Dilophosaurus or Allosaurus—likely produced the largest prints, exceeding 12 inches in length. In contrast, the footprints of the largest theropods, such as Tyrannosaurus rex or Giganotosaurus, typically exceed 16 inches.
Variations in track depth across the site reveal a spectrum of speeds and gaits, enabling paleontologists to estimate the size and movement patterns of the track-makers with greater precision.
Although researchers have long suspected that enormous numbers of ancient footprints existed, this study marks the first rigorous, comprehensive examination of Carreras Pampa itself.
To study the site in detail, scientists meticulously removed obstructions and sediment from key impressions to uncover hidden tracks and better understand the broader layout of the track networks.
Bolivia also hosts Cal Orck’o, another fossil bed roughly 250 miles southeast of Carreras Pampa, which houses a dense collection of dinosaur footprints. Together, these sites contribute to Bolivia’s reputation for one of the most extensive and diverse compilations of dinosaur track records, spanning the Triassic, Jurassic, and Cretaceous periods.
