Scientists in Denali National Park have made an amazing find: the largest dinosaur tracks ever discovered in Alaska, known as “The Coliseum.” This site, filled with thousands of fossilized footprints, dates back about 70 million years to the Late Cretaceous period.
Researchers from the University of Alaska Fairbanks highlighted how this discovery provides a glimpse into a long-lost ecosystem that thrived in Interior Alaska. Their study was published in Historical Biology.
At first glance, the site seemed unremarkable. It looked like any rocky patch in Alaska. But as the sun began to set, something remarkable happened—the tracks became visible. The area stretches over a space similar to a small shopping center, showcasing multiple layers of dinosaur footprints, unlike smaller sites previously found in Denali.
“It’s not just one level of rock with tracks on it; it’s a sequence through time,” said Dustin Stewart, the lead author of the study. Initial observations revealed only a handful of tracks. But as the light shifted, hundreds more appeared, leaving the team in awe.
The rock walls at The Coliseum rise over 20 stories. These cliffs were once part of a muddy floodplain where dinosaurs left their marks in soft sediment. Geologic shifts later exposed these fossil-rich surfaces. Some tracks are preserved as direct impressions, while others feature natural casts. Stewart noted some prints retain detailed toe shapes and traces of skin texture.
The discovery didn’t stop at footprints. The team also found fossilized plants, pollen grains, freshwater shellfish, and small invertebrates. Together, these remains help scientists reconstruct the environment of 70 million years ago, which resembled today’s Pacific Northwest—rich with conifer and deciduous trees, ferns, and horsetails.
“These clues help piece together what the environment looked like as a whole,” Stewart explained.
Most of the dinosaur tracks belong to large herbivores, particularly duck-billed and horned dinosaurs. Both juvenile and adult tracks suggest this area saw repeated visits over thousands of years. Predatory footprints from raptors and tyrannosaurs were also discovered, as well as smaller tracks likely made by birds and flying reptiles.
Pat Druckenmiller, director of the University of Alaska Museum of the North, emphasized how different this prehistoric world was compared to modern Denali. “There was a tyrannosaur roaming here many times the size of the largest brown bear we see today. It was a vibrant ecosystem with raptors, flying reptiles, and birds,” he noted.
The National Park Service now protects this important site, planning to continue research as new layers of tracks and fossils are examined. This discovery not only enriches our understanding of Alaska’s prehistoric past but also serves as a reminder of the diverse life forms that once roamed this landscape.
For more insights into Alaska’s geological history, you can explore related studies published in journals like Historical Biology.
