Bolivia’s Carreras Pampas reveals unprecedented dinosaur trackways
Over 16,000 fossilized footprints unearthed in Bolivia present a vivid glimpse into the movements of theropod dinosaurs from over 100 million years ago. These tracks, preserved along an ancient shoreline, offer rare insights into how these predators navigated their environment during the late Cretaceous period.
The Carreras Pampas site, located within Bolivia’s Torotoro National Park, has yielded a remarkable concentration of theropod footprints, with scientists recently identifying 16,600 impressions. This surpasses any previously documented tracksite in terms of sheer volume. The preserved tracks span roughly 80,570 square feet (7,485 square meters) and include both isolated prints and continuous trackways, which trace the paths of individual animals. The study, published in PLOS One, marks the first detailed scientific survey of this exceptional site.
A bustling dinosaur highway
Paleontologists describe Carreras Pampas as a “dinosaur freeway,” where theropods traveled repeatedly across soft, deep mud between 101 million and 66 million years ago. Researchers suggest that the tracks, mostly aligned in north-northwest and southeast directions, were formed over a relatively short period, indicating that this area was a frequently used corridor for these carnivorous dinosaurs. Such a concentration of tracks hints at a larger network of movement that may have extended across parts of Bolivia, Argentina, and Peru.
The dimensions and distribution of the footprints demonstrate a variety of behaviors. Some theropods strolled casually along the muddy shore, whereas others dashed, creating longer and deeper prints. Notably, more than 1,300 tracks indicate swimming activity, with the middle toe impressing more deeply into the mud, while the other toes and heel left lighter traces. These observations provide a distinctive perspective on how dinosaurs engaged with water and maneuvered through their environment.
Insights from footprint dimensions
Analysis of footprint dimensions reveals a broad spectrum of theropod sizes, with estimated hip heights ranging from approximately 26 inches (65 centimeters) to over 49 inches (125 centimeters). Some trackways even feature tail drag marks, offering further insights into the animals’ movements. Alongside the theropod tracks, researchers recorded several hundred bird footprints that coexisted along the shoreline, offering a window into the wider ecosystem of that era.
“The tracks offer a comprehensive account of movement and surroundings,” stated Dr. Peter Falkingham, a paleobiology professor at Liverpool John Moores University, who did not participate in the study. “Deeper impressions document the foot’s motion in ways that skeletal remains cannot, unveiling gait, posture, and interactions with the substrate.”
Swimming tracks, for instance, differ markedly from walking tracks, as buoyancy alters how the toes press into the mud. These subtle variations help paleontologists reconstruct behaviors that bones alone cannot convey. Dr. Jeremy McLarty, coauthor of the study, noted, “Tracks are a record of soft tissues, of movements, and of the environments the dinosaurs were actually living in. Carreras Pampas brings these lost ecosystems to life.”
Comparing trackways across Bolivia
Although Carreras Pampas has been known for its dinosaur footprints since the 1980s, the scale and density had never been systematically studied. Bolivia boasts multiple tracksites dating from the Triassic, Jurassic, and Cretaceous periods, making it one of the richest regions in the world for dinosaur trackways. Prior to the Carreras Pampas survey, the most prolific site was Cal Orck’o in Sucre, which contains roughly 14,000 tracks from about 68 million years ago.
The predominance of theropod footprints at Carreras Pampas raises questions about the ecosystem dynamics of the time. Unlike sauropods, which traveled in herds, theropods were typically solitary predators. This tracksite, dominated by carnivorous dinosaurs, may indicate localized hunting grounds or a migration route heavily trafficked by these agile hunters. McLarty emphasized, “When you start comparing across sites, you can begin to see patterns of dinosaur movement on a continental scale.”
Insights from trackways that fossils alone cannot provide
Unlike skeletal fossils, which may be displaced from their original locations after death, trackways provide a direct snapshot of life in motion. “A skeleton shows what an animal could do; trackways show what it actually did,” explained Dr. Anthony Romilio, a research associate at the University of Queensland. Trackways capture speed, direction, turning behavior, slipping, posture, and, in some cases, group interactions.
The Carreras Pampas site holds particular significance as it maintains a range of theropod sizes, potentially indicating various species or age categories. The richness and variety of footprints deliver insights into population composition, predator-prey interactions, and the manner in which distinct species coexisted within the same environment. The tracks further offer proof of recurrent usage over time, implying that this shoreline served as a crucial passageway within the Cretaceous landscape.
Implications for paleoecology
By examining footprint depth, shape, and spacing, scientists can infer not only dinosaur size and behavior but also the characteristics of the substrate and the environmental conditions at the time. The soft, deep mud preserved at Carreras Pampas captured subtle details such as foot rotation, claw marks, and tail drags, all of which illuminate how these animals moved through their environment.
These discoveries have wider implications for comprehending the ecology of late Cretaceous South America. They assist in reconstructing predator-prey dynamics, shoreline utilization, and even possible seasonal trends in dinosaur migration. Moreover, the blend of theropod and avian tracks offers a more comprehensive view of the Cretaceous ecosystem, emphasizing the interaction between large predators and smaller species that coexisted.
Preserving a window into the past
Carreras Pampas demonstrates the power of trackways to preserve moments of prehistoric life in a way that bones alone cannot. Visitors to the site stand literally where dinosaurs once walked, leaving behind a record of motion frozen in time. McLarty noted, “Tracks don’t move. When you visit Carreras Pampas, you know you are standing where a dinosaur walked.”
The sheer number and diversity of footprints make this site a valuable resource for ongoing research. Future studies may compare Carreras Pampas with other Bolivian sites to understand regional patterns of dinosaur behavior and movement. By mapping and analyzing these trackways, scientists can better grasp how theropods navigated landscapes, hunted, and interacted with both conspecifics and other species.
Moreover, the site emphasizes the significance of safeguarding fossil trackways, which provide invaluable insights into ancient life. Every footprint depicts a brief moment from millions of years past, illustrating the dynamics of extinct creatures in a manner that skeletal remains cannot achieve.
The Carreras Pampas tracksite in Bolivia offers an exceptional record of theropod activity and behavior, showcasing the movements, sizes, and interactions of dinosaurs along an ancient shoreline. These fossilized footprints are more than mere impressions in stone—they are vivid snapshots of prehistoric life, providing scientists and the public alike with a rare chance to witness the Cretaceous world as it once existed. The detailed analysis of these tracks not only enhances our understanding of dinosaur ecology but also enriches the global picture of how these iconic predators shaped and navigated their environments millions of years ago.
