Paleontologists have discovered tens of thousands of dinosaur tracks in Bolivia, providing insights into the species that roamed an ancient coastline. Nearly 18,000 tracks have been identified at the Carreras Pampa track site in Torotoro National Park. This includes 16,600 footprints, 1,378 swim tracks, and several tail traces, according to a study published in the journal PLOS One.

The tracks extend in a northwest-southeast direction, suggesting how dinosaurs and other animals navigated the paleocoastline. Most of the tracks belong to theropods, a group of bipedal dinosaurs from the Cretaceous period, which includes the famous Tyrannosaurus rex. Some tracks are also attributed to birds, with the imprints dating back between 145 million and 66 million years.

Carreras Pampa covers approximately 80,570 square feet and is noted for having the most preserved dinosaur footprints and the highest number of dinosaur swim trackways globally. The site showcases how dinosaurs walked, ran, swam, and even dragged their tails, providing a glimpse into their behavior.

The swim tracks were likely created when theropods scratched the water's bottom with their middle toes, forming grooves that appear either straight or curved. Researchers analyzed over 1,275 trackways, noting that while many sites feature individual swim tracks, Carreras Pampa displays alternating swim tracks from the right and left feet.

The variety in track shapes and sizes indicates that multiple dinosaur species traversed this ancient coastline. Some footprints measured less than 4 inches, which is rare in the fossil record. Researchers believe these small tracks may belong to a smaller theropod species, such as Coelophysis, or juvenile larger species.

Larger footprints, exceeding 12 inches, are likely from mid-sized theropods like Dilophosaurus or Allosaurus. The largest footprints, typically over 16 inches, are attributed to larger theropods, including T. Rex and Giganotosaurus. The depth of the tracks varies, allowing researchers to estimate the speeds, gaits, and sizes of the dinosaurs that made them.

This study marks the first comprehensive examination of the Carreras Pampa track site, where researchers meticulously cleared debris and sediment to uncover additional tracks. Bolivia is also home to the Cal Orck'o track site, located about 250 miles southeast of Carreras Pampa, which contains a significant concentration of dinosaur tracks. The country boasts one of the most extensive records of dinosaur track sites, spanning the Triassic, Jurassic, and Cretaceous periods.