Deep in Bolivia’s Andes lies a remarkable stone surface: a 1.85-acre expanse covered with dinosaur footprints that have beenfrozen in limestone for 66 million years.
Local paleontologists long suspected Carreras Pampa held extraordinary treasures, but no one had systematically studied the site.
The remote location had been dismissed as a geological curiosity. Recently, a determined research team arrived with modern tools to unlock its secrets.
A Hidden Record Emerges
In 2021, Jeremy McLarty and his international team reached Torotoro National Park and encountered something remarkable: a carbonate surface with unmistakable imprints from animals that had walked, run, and swum across an ancient shoreline.
They swept away debris, measured trackways with centimeter precision, created 3D digital scans, and documented the orientation and depth of every impression.
This meticulous approach revealed complexity that casual observation could never capture.
Bolivia’s Fossil Tradition
Bolivia ranks as a major paleontological hotspot, containing dinosaur tracksites from the Triassic, Jurassic, and Cretaceous periods—an unmatched geological archive in South America.
The El Molino Formation, which contains Carreras Pampa, represents the final chapter of the Cretaceous period, when the region shifted from a shallow sea to coastal environments.
Bolivia’s position on the ancient supercontinent Gondwana preserved diverse ecosystems. Carreras Pampa became the crown jewel.
Breaking the Previous Record
Before December 2025, another Bolivian site held the world record: Cal Orck’o, near Sucre. Discovered in 1994 during limestone quarrying, workers mapped Cal Orck’o between 1998 and 2015, finding 12,092 individual dinosaur tracks across 465 trackways.
This extraordinary number remained unchallenged for a decade, cementing Cal Orck’o’s status as the world’s premier tracksite. Then Carreras Pampa shattered this record dramatically.
18,000 Tracks Documented
On December 3, 2025, researchers published findings in PLOS One: Carreras Pampa contains 16,600 theropod footprints and 1,378 swim tracks, totaling approximately 18,000 individual impressions —the highest ever recorded at one location.
This represents a stunning 50 percent jump over Cal Orck’o. The discovery spans 80,570 square feet, with tracks spaced roughly one every 4.5 square feet.
“Everywhere you look on that rock layer, there are dinosaur tracks,” McLarty noted.
Torotoro’s Significance for Paleontology
Torotoro National Park, established in 1989, covers 165 square kilometers in northern Potosí, roughly 140 kilometers south of Cochabamba.
The park rises between 2,000 and 3,500 meters, featuring dramatic karst terrain: deep canyons exceeding 300 meters, caves, dolines, and wind-eroded formations carved from fossil-rich Paleozoic and Cretaceous limestone.
Before systematic documentation of Carreras Pampa, Torotoro held over 3,500 dinosaur footprints scattered across multiple exposures.
A Window Into Ecosystem Behavior
Carreras Pampa’s track sizes and morphologies reveal a thriving ecosystem with multiple theropod species.
Footprints range from tiny impressions under 4 inches long—possibly from juvenile dinosaurs or small species like Coelophysis—to large prints exceeding 12 inches, possibly from mid-sized theropods like Dilophosaurus or Allosaurus.
The absence of giant T. rex-sized prints suggests that smaller and medium-sized predators dominated this ancient shoreline, revealing a complex food web.
Behavioral Signatures Preserved in Stone
Carreras Pampa transforms from a footprint inventory into a behavioral archive through the preservation of evidence of movement and decision-making.
Trackways demonstrate walking, running, sudden turns, tail-dragging, and swimming—behaviors that skeletal remains alone cannot reveal. Most footprints follow consistent northwest-southeast orientations, suggesting dinosaurs traveled together along established pathways.
Some tracks show sprint acceleration patterns; others display leisurely strides, indicating casual foraging. This diversity reveals dinosaurs using the site under varying conditions.
The Swimming Revolution
The 1,378 swim tracks represent perhaps Carreras Pampa’s most groundbreaking discovery—the highest number of swimming impressions ever documented at one site.
These tracks differ from walking impressions: they appear as straight or comma-shaped grooves in alternating left-right patterns, created when theropods used their middle toes to scratch shallow water sediment.
Left-right alternating swim tracks remain extraordinarily rare in paleontology. Carreras Pampa documents sustained aquatic locomotion, proving that theropods were confident swimmers.
Nine Sites, One Surface
Carreras Pampa’s 18,000 tracks concentrate on a single carbonate-cemented tracking surface exposed across nine study zones (CP1 through CP9), showing remarkable continuity.
The two largest sites, CP1 and CP2, collectively cover approximately 4,984 square meters. This concentration suggests tracks accumulated during a geologically brief interval—possibly days, weeks, or a few years—when this location served as a high-traffic corridor.
All nine sites expose identical tracking surfaces with similar geology, indicating dinosaurs repeatedly returned.
The End of the Dinosaurs
All Carreras Pampa tracks date to the very end of the Cretaceous period—between 101 and 66 million years ago, with most evidence suggesting that final deposits formed just before the K-Pg extinction event.
These dinosaurs walked this shoreline moments before an asteroid impact near Mexico’s Yucatán Peninsula triggered a global catastrophe.
The 180-kilometer Chicxulub crater, dated to precisely 66.043 million years ago, unleashed an impact winter that darkened skies, halted photosynthesis, and eliminated roughly 75 percent of species within approximately 32,000 years.
From Debris to Discovery
Carreras Pampa fieldwork required painstaking preparation. Researchers swept away accumulated debris and rocks, clearing centuries of accumulation that had obscured the impressions.
They then employed multiple documentation techniques, including high-resolution photography with centimeter-scale references, 3D photogrammetry to create digital surface models, precise measurements of track length and depth, and hand-drawn tracings on transparent material.
Teams systematically mapped specific areas with chalk markings to establish accurate density measurements.
Density Patterns Reveal High-Traffic Conditions
Track distribution analysis reveals striking patterns in site use. Across most study zones, average track density reached 2.61 impressions per square meter—roughly one footprint per 4.5 square feet.
In the densest sections, density reached 3-4 impressions per square meter, suggesting crowded conditions where dinosaurs frequently traversed identical paths.
This concentration pattern reflects major migration events, preferred habitat, or critical resources rather than isolated, random visitation.
Tail Traces and Unusual Preservation
Carreras Pampa’s exceptional preservation of tail traces—drag marks left when dinosaur tails contacted ground—ranks among its most scientifically valuable aspects.
The site preserves “one of the highest numbers of dinosaur tail traces anywhere in the world,” according to McLarty. Tail traces provide indirect evidence of an animal’s posture and body mechanics.
Dragging tails suggest slow movement or stress; elevated tails indicate confident, speedy movement. Some unusual tail configurations suggest injury, aging, or deliberate adaptation to wet substrates.
A Larger Dinosaur Freeway Hypothesis
The consistent northwest-southeast orientation of Carreras Pampa tracks, combined with geological evidence of ancient coastal conditions, suggests that this site belonged to a larger regional migration corridor.
McLarty and colleagues propose a “dinosaur freeway” that potentially spans Argentina, Bolivia, and Peru—a continuous pathway that theropods repeatedly traversed across Gondwanan landscapes.
If correct, Carreras Pampa represents an exceptionally well-preserved window into a continental-scale system of dinosaur movement and behavior operating over millions of years of the Late Cretaceous period.
Comparative Paleontology and Reinterpretation
Carreras Pampa findings already reshape how paleontologists interpret other dinosaur tracksites globally.
Lark Quarry in Queensland, Australia, previously interpreted as evidence of a panic stampede, has been reinterpreted: rather than chaos, Lark Quarry likely documents sustained river crossing by multiple dinosaur groups over extended intervals, with some swimming, others wading, and larger animals walking across deeper sections.
This demonstrates how one exceptionally well-documented site illuminates the global paleontological record, positioning Bolivia as the epicenter of trackway science.
Future Research Directions and Related Discoveries
The PLOS One paper notes that “many more footprints remain to be explored at this tracksite and others in Bolivia.”
McLarty’s team plans to investigate additional Torotoro tracksites and beyond, correlating track patterns across locations to reconstruct larger ecosystem dynamics.
At Southwestern Adventist University, McLarty collected 3D digital trackway scans, enabling student researchers to conduct analyses without requiring field travel, thereby democratizing paleontological discovery.
Integrating Carreras Pampa data with ongoing research on theropod evolution and swimming biomechanics promises novel insights into Late Cretaceous dinosaur ecology.
Public Reception and Social Context
Carreras Pampa captured global media attention, appearing in major outlets such as CNN and Live Science, as well as BBC Newsround, with social media amplifying the footprint-covered surface images.
The story resonates by combining tangible evidence—actual dinosaur footprints—with scientific rigor and dramatic narrative. However, casual interpretations oversimplified findings, with some headlines suggesting single-event “stampedes.”
More nuanced coverage emphasized tracks accumulated over days, weeks, or months, representing repeated use. McLarty actively clarified these distinctions, explaining preservation conditions and temporal resolution.
Bolivia’s Role in Paleontology
Carreras Pampa joins Bolivia’s paleontological achievements. Cal Orck’o’s 12,092 tracks, documented between 1998 and 2015, previously held the global record and significantly transformed our understanding of Late Cretaceous diversity.
Bolivia yielded significant skeletal fossils spanning the Mesozoic Era. The El Molino Formation has contributed multiple discoveries, making it one of Earth’s most scientifically productive strata.
Historically overlooked in English-language literature, Bolivia’s back-to-back world-record tracksites—Cal Orck’o and Carreras Pampa—definitively repositioned it as a premier paleontological destination.
Why This Matters
Carreras Pampa represents a paradigm shift in paleontological science: a comprehensive, well-documented dataset offering something skeletal remains cannot—direct evidence of how dinosaurs moved, behaved, and lived in their ecosystems.
The 18,000 tracks spanning nine sites reveal communities, populations, and behavioral patterns frozen in stone for 66 million years. These dinosaurs thrived on a shoreline moments before extinction.
For researchers and educators alike, Carreras Pampa crystallizes a profound truth: sometimes the most powerful window into the deep past comes not from what animals left behind, but from the paths they literally walked.
Sources:
- PLOS One, December 3, 2025
- Jeremy McLarty, SWAU
- CNN, December 4, 2025
- Britannica, K-T Extinction
- Wikipedia, Cal Orck’o
- BBC Newsround, December 5, 2025