16,000 dinosaur footprints found at world’s largest track site

The rocky flats of Bolivia’s Carreras Pampas are telling a story that bones alone can’t: an enormous, well-preserved record of dinosaur movement. Scientists mapping the site have uncovered thousands of footprints pressed into what was once a muddy channel, revealing behaviors, groupings and routes that illuminate how these animals lived and traveled.

Field researchers describe a carpet of three-toed impressions stretching across the landscape — a snapshot of activity frozen for tens of millions of years. The size, spacing and orientation of these marks give paleontologists rare, direct evidence of how theropod dinosaurs walked, ran, waded and possibly migrated across ancient South America.

Bolivia’s jaw-dropping dinosaur tracksite: numbers and setting

In the heart of Torotoro National Park, teams have cataloged an astonishing 16,600 individual footprints, grouped into dozens of distinct trackways. These impressions lie on a single remnant surface that once bordered a watercourse, now exposed by erosion and time. The scale of the deposit makes it one of the most extensive dinosaur tracksites yet documented anywhere on Earth.

The prints come from theropods — the bipedal, mostly carnivorous dinosaurs that include the lineage leading to T. rex. Some tracks are isolated prints, while others form coherent series showing repeated travel in the same direction. At the same time, a variety of stride patterns suggests that some animals paused, others moved steadily, and a few appear to have been wading or swimming when they left impressions.

What footprints tell us that bones cannot

Unlike skeletons, footprints lock a dinosaur in place at a precise moment. From the rock record at Carreras Pampas, researchers can infer movement, posture, and behavior in ways bones rarely allow. Key pieces of information derived from the trackways include:

• Estimated body size based on footprint dimensions.
• Speed estimates derived from stride length and spacing.
• Locomotor details such as tail contact, toe impressions, and changes in gait.
• Possible social behavior, when multiple trackways overlap or run in parallel.

Track morphology reveals subtle details: narrow toe prints and long stride lengths point to faster movement, while closely spaced impressions and turning paths indicate low-speed maneuvering or high hip mobility. Occasional drag marks and varied toe depth also hint at uneven ground or shallow water conditions where some theropods were partially buoyant.

Estimating size, speed and health from tracks

Scientists use simple geometric relationships to translate a footprint into body metrics: a larger print generally equates to a larger animal, and the distance between prints helps estimate pace. Variations within a single trackway can suggest injured limbs, young animals traveling with adults, or responses to changing terrain. At Carreras Pampas, prints range from those made by relatively small theropods — perhaps two feet at the hip — to larger individuals approaching three feet at hip height.

How researchers documented and interpreted the site

The study, published in PLOS One, combined field surveys, photogrammetry and mapping to register thousands of imprints. Researchers carefully recorded orientation and alignment across the deposit, noting that many trackways trend roughly north-northwest or southeast. This repeated directionality implies a preferred route across an open landscape, perhaps part of a seasonal corridor stretching toward what is now Argentina.

Dr. Jeremy McLarty, who helped lead the work, emphasized the uniqueness of the site: when walking on the fossil surface, visitors stand literally where dinosaurs once stepped. Team members concluded that a large proportion of the prints were created within a relatively short span of time geologically, producing a remarkably concentrated snapshot of activity.

Evidence for group movement and varied behaviors

Some sets of trackways run parallel or overlap in ways that suggest multiple animals moved through the area together or along the same path days or weeks apart. Other impressions show back-and-forth motion, consistent with foraging or pacing, while shallow, widely spaced marks indicate wading or swimming behavior through a muddy channel. Together these patterns give a multi-dimensional view of daily life for these theropods.

Age, geological context, and related discoveries worldwide

Geological analysis places the Carreras Pampas prints near the end of the Cretaceous Period, roughly between 100 and 66 million years ago. That timing situates the site among other significant Late Cretaceous tracksites across Gondwana, where similar fossilized footprints preserve snapshots of dinosaur behavior just before the mass extinction event.

Comparable discoveries elsewhere reinforce how footprints complement fossil bones:

• Beachside imprints discovered by visitors that reveal large, three-toed prints exposed by erosion.
• Centuries-old agricultural and construction sites where ancient walks were found beneath modern surfaces.
• Riverbeds that periodically dry and reveal well-preserved tracks after droughts.

Outside specialists who reviewed the Carreras Pampas work told media outlets they were excited to see such a concentrated record. The site provides fertile ground for future research aimed at linking specific track morphologies to theropod groups and reconstructing how these animals used ancient South American landscapes.

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Michael Thompson

Michael Thompson is an experienced journalist covering U.S. and global news. With ten years on the front lines, he breaks down political and economic stories that matter. His precise writing and keen attention to detail help you grasp the real‑world impact of every event.