A New World Record: Thousands of Dinosaur Tracks in Bolivia
In the final days of the dinosaurs' reign, approximately 16,600 footprints were pressed into wet mud along a shoreline in central Bolivia. These tracks now form a single exposed rock surface in Torotoro National Park, revealing a bustling scene frozen in time.
The discovery, led by paleontologist Raúl Esperante from the Geoscience Research Institute in California, showcases a busy route used by dinosaurs. The research focuses on ancient coastal environments and how dinosaur tracks can provide insights into behavior and habitat.
The site, known as Carreras Pampa, is located in a small valley where erosion exposed a flat slab of gray limestone. This surface covers just under two acres and belongs to a single layer of rock that once lay on a coastal plain.
The team marked off nine study zones on the rock surface, where footprints cluster in different concentrations. These zones are on the same flat rock sheet, so all tracks come from nearly the same moment in geologic time.
The researchers counted 1,321 continuous paths and 289 lone prints, representing individual animals moving across the surface in separate passes. All the measured footprints were made by three-toed theropods, the mostly meat-eating dinosaurs that walked on two legs, or by their close bird relatives.
Each line of footprints, called a trackway, records one animal as it moved across the mud. Paleontologists analyze the spacing, depth, and shape of the prints to estimate speed, body size, and how the animal balanced with each step.
At Carreras Pampa, many trackways have long stride lengths and narrow step patterns, indicating animals moving at a steady running pace. This site has a larger proportion of trackmakers moving at a faster gait compared to other dinosaur sites.
The footprints also reveal traces of walking and swimming. In some areas, the footprints plunge into deep-walled pits, indicating soft and waterlogged ground. Nearby, shallow claw scratches and sinuous grooves show moments when toes scraped the bottom and tails dragged behind dinosaurs moving through shallow water.
This detailed study confirms that Carreras Pampa holds the record for the greatest number of dinosaur footprints ever recorded at a single site. The same region also set records for the number of trackways, tail traces, and continuous swimming trails preserved on one rock surface.
The exposed slab is dense with footprints, with a few in every square yard of rock. This density makes Carreras Pampa an ideal natural classroom for ichnology, the study of fossil tracks and other movement traces.
Most dinosaur tracksites around the world are sparser, preserving only a few dozen impressions with large stretches of bare stone between sets of prints. At Carreras Pampa, most footprints point northwest to southeast, matching the orientation of tiny ripple ridges in the rock that mark an ancient paleocoastline.
Some trackways run side by side for many steps without crossing, suggesting small groups of dinosaurs pacing along the same watery route at different times. Deeper pits and tail drags often cluster in slight depressions, indicating areas that stayed wetter longer.
In a few places, tightly curved paths record sharp turns, showing dinosaurs slowing, pivoting, and then setting off in a new direction – a behavior rarely captured in the fossil record. This site adds a new perspective, showing a community dominated by small and medium theropods living close to the waterline.
The research team has also described other Bolivian tracksites with swim traces, sudden stops, and unusual kicking marks preserved in similar rocks. The study is published in the journal PLOS One.
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