Researchers record more than 16,000 footprints in the largest dinosaur tracksite in the world

A once-bustling "dinosaur highway" may have traversed the shores of present-day Bolivia, where carnivorous, bipedal theropods left behind thousands of fossilized footprints. Paleontologists have now analyzed these tracks in detail, offering an unprecedented view of dinosaur activity in this region.

At the Carreras Pampas site in Bolivia's Torotoro National Park, scientists documented 16,600 theropod printsmore than any other known location worldwide. These footprints, dating from 101 to 66 million years ago during the late Cretaceous period, were pressed into soft mud as the dinosaurs moved across the landscape.

This research represents the first comprehensive survey of the area, which covers approximately 80,570 square feet (7,485 square meters). Some prints were isolated, but many formed trackways, showing repeated movement by individual dinosaurs, according to a report in PLOS One.

The rock layer is saturated with dinosaur tracks, said Dr. Jeremy McLarty, coauthor of the study and director of the Dinosaur Science Museum and Research Center in Texas. Most prints indicate movement toward the north-northwest or southeast, suggesting this location was part of a broader corridor stretching through Argentina, Bolivia, and Peru.

By analyzing footprint shapes and spacing, researchers could infer the dinosaurs movement: some walked leisurely, others ran, and over 1,300 prints even suggest swimming through shallow water. Certain trackways show tail drag marks, and footprint dimensions reveal a wide range of theropod sizesfrom roughly 26 inches (65 cm) to more than 49 inches (125 cm) at the hip. Additional prints were made by birds that coexisted along the shoreline.

Experts not involved in the study highlighted the significance of these discoveries. Paleontologist Sally Hurst noted that identifying thousands of prints and their varied gaits provides valuable insights into ancient ecosystems and how dinosaurs and birds interacted with them.

The footprints preservation in previously soft, deep mud allows detailed reconstruction of movement. Dr. Peter Falkingham, a paleobiologist at Liverpool John Moores University, explained that deeper impressions capture more of the foots motion, giving researchers a richer understanding of dinosaur locomotion.

Swimming tracks are distinct, with the central toe leaving a deeper mark while the other toes and heel appear lighter. Such traces capture soft tissue, movement, and environmental interaction, offering a vivid glimpse of ecosystems that skeletal remains alone cannot convey.

Although Carreras Pampas has been known since the 1980s for its dinosaur tracks, the scope and detailed study of the site are recent. The findings raise questions about why theropods dominate the footprint record here, unlike other sites that often show herbivorous sauropods traveling in groups.

Bolivia is home to multiple trackway sites from the Triassic, Jurassic, and Cretaceous periods. Before Carreras Pampas, the largest known site was Cal Orcko near Sucre, with roughly 14,000 footprints dating to 68 million years ago. Comparing these sites may reveal broader patterns of dinosaur movement across South America.

Tracks offer unique insight into living behavior: while skeletons indicate potential capability, footprints show actual movement, speed, direction, posture, and interactions. The Carreras Pampas site preserves multiple theropod sizes, likely reflecting different species or age groups.

Unlike bones, which may shift after death, tracks remain where dinosaurs walked, providing a direct snapshot of ancient activity. When you visit Carreras Pampas, you are standing where a dinosaur once walked, McLarty emphasized, illustrating the sites exceptional value for understanding prehistoric life.

Author: Ava Mitchell