In the central highlands of Bolivia, there are giant three-toed footprints that, according to legend, originated from powerful monsters whose claws could penetrate stone. However, during the 1960s, researchers came to the region to alleviate children’s fears, revealing that these unusual prints were actually left by a giant two-legged dinosaur that thrived in the ancient waterways near modern Toro Toro, a village and national park in the Bolivian Andes, over 60 million years ago.
Recently, a group of paleontologists from Loma Linda University in California discovered and carefully cataloged an impressive 16,600 footprints made by theropods, a category of dinosaurs that includes the notorious tyrannosaurs. Their findings, based on six years of fieldwork, were published last Wednesday in the journal PLOS One, marking this as the greatest accumulation of theropod footprints identified globally.
Roberto Biaggi, one of the study’s co-authors, emphasized the uniqueness of this location, stating, “Nowhere else in the world are there so many (theropod) footprints.” This area holds multiple world records for such findings.
Prints that capture dinosaur behavior
The dinosaurs that roamed this land didn’t just wander; they also attempted to swim, scratching at the lake bed and leaving behind 1,378 footprints, as per the study. Researchers note that the dinosaurs pushed their claws into the mud just before rising water levels covered their prints, which ultimately helped preserve them over the millennia.
Richard Butler, a paleontologist at the University of Birmingham who wasn’t involved with the study, commented on the excellent condition of many of the footprints. He expressed amazement at the unprecedented number and variety found in Toro Toro.
Butler also remarked that these findings provide a fascinating glimpse into the lives of dinosaurs during the late Cretaceous period, around 66 million years ago, a time that ended with a catastrophic asteroid impact wiping out the dinosaurs along with 75 percent of species alive today.
Preservation challenges for the footprints
Despite surviving for millions of years, human activities pose a threat to these ancient imprints. For years, farmers have cultivated crops on the footprint-laden plateau, and quarry workers often disregarded the significance of the rock formations during limestone excavation. Additionally, just two years ago, a highway construction crew inadvertently destroyed many major dinosaur footprints before national park authorities could intervene.
This situation can be linked to the surprising scarcity of dinosaur bones, teeth, and eggs in the region. Despite finding numerous footprints and swimming tracks in Toro Toro, the lack of skeletal remains is in stark contrast to the fossil-rich landscapes of Argentina’s Patagonia and Brazil’s Campaña.
The researchers noted that the specific pattern and extent of the footprints suggest that these dinosaurs didn’t settle permanently in Bolivia. Instead, they likely traveled along an ancient coastal route that extended from southern Peru to northwestern Argentina.
The varying sizes of the footprints hint at the presence of a massive creature, roughly 10 meters (33 feet) tall, moving alongside smaller theropods about the size of a chicken, with a waist height of 32 centimeters (1 foot).
Anthony Romilio, a paleontologist from the University of Queensland in Australia, although not part of this study, explained that footprints provide insights into daily dinosaur behavior that skeletons cannot. By studying these prints, researchers can understand when the dinosaurs moved, accelerated, halted, or changed direction.
The reason for the dinosaurs’ presence remains unclear
However, it’s still uncertain why these dinosaurs congregated in such large numbers on this open plateau. Romilio speculated that they might have regularly visited ancient freshwater lakes and the expansive muddy shorelines surrounding them. Biaggi pondered if they were perhaps fleeing from something or searching for a calm place.
One thing is for sure: research into this remarkable collection of dinosaur footprints will persist. Biaggi expressed optimism about future investigations, suggesting, “I suspect this will continue for many years and we will find more footprints on the edges of what has already been discovered.”
