16,000 Fossilized Footprints Reveal South America’s Forgotten Dinosaur Highway

Bolivia’s arid Carreras Pampa is home to a prehistoric treasure that paleontologists once overlooked. Thousands of dinosaur footprints are strewn across the dusty landscape, silent impressions that now tell a living story of how ancient reptiles moved, traveled and even swam across what is now South America. Researchers suggest that the region may have once served as a major travel route for dinosaurs, a dinosaur highway, so to speak.

In a new study published in PLOS OneResearchers from California’s Geoscience Research Institute, in collaboration with other scientists, describe an astonishing variety of dinosaur tracks preserved at the Carreras Pampas site in Torotoro National Park. Across nine study areas, the team documented more than 16,000 individual footprints, making it the most extensive dinosaur track site ever discovered.

Learn more: Could the remarkable footprints of prehistoric amphibians be older than those of dinosaurs?

Fossilized footprints give clues to how dinosaurs moved

All traces belong to three-toed theropods, a group of bipedal dinosaurs best known for including top predators like T. rex. But these Bolivian builders came in all sizes. Some prints are less than four inches long, while others exceed a foot in length, hinting at a mixed specimen passing through the area.

Even more impressive than the number of tracks is what they reveal about dinosaur behavior. Fossilized footprints record animals running, making sharp turns, dragging their tails and, in some cases, moving through water.

But how can scientists extract this level of detail from simple footprints?

“Some movement information is preserved directly in the pathways, such as pathways that turn or have associated tail traces,” says Jeremy A. McLarty, a professor in the Department of Biological Sciences at Southwestern Adventist University. “Other movement reconstructions are based on comparisons with living animals, such as whether the dinosaur walked or ran and how fast it moved.”

Bolivia has perfect conditions for preserving dinosaur footprints

The Carreras Pampas site already attracted the attention of scientists in 2015, when Torotoro National Park rangers pointed it out to researchers. Follow-up visits only increased their enthusiasm.

“During our research, we were amazed by the abundance and variety of trace fossils preserved at the site,” says McLarty. Researchers describe the area as “a stunning window into this region’s past,” according to a press release.

Bolivia is already renowned for its dinosaur track sites, which preserve footprints spanning nearly 200 million years, from the Triassic to the Cretaceous. The unique combination of soft sediments, stable geology and rich dinosaur populations appears to have created ideal conditions for fossilizing the footprints before they erode.

Some researchers believe this region may once have been “part of a dinosaur highway across South America,” McLarty adds.

The authors also note that many other footprints remain unexplored at Carreras Pampa and other track sites in Bolivia.

Read dinosaur tracks around the world

Most Carreras Pampas trails have a distinct orientation: northwest to southeast. Ripple marks in the sediment reveal the presence of an ancient shoreline, suggesting that dinosaurs followed the edge of a long-lost body of water during their journey.

The site now sets world records for the number of individual dinosaur footprints, continuous tracks, tail tracks and swimming tracks discovered in a single location. The incredible abundance reinforces the idea that Carreras Pampa was a high-traffic area for dinosaurs, and the parallel orientation of some tracks even raises the possibility that groups of dinosaurs traveled together.

The research team is already working on additional projects to uncover more details hidden in the traces. They also hope to expand their research to other little-studied regions of Bolivia.

McLarty thinks the Bolivian track sites could help direct research elsewhere. With so many footprints preserved in one place, the site offers a rare opportunity to compare movement patterns and behaviors across age groups and conditions, data that could inform how scientists interpret dinosaur tracks around the world for years to come.

Learn more: Trail of sauropod dinosaur footprints provides insight into life in the Middle Jurassic

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