BOZEMAN, Mont. —- Visitors strolling through the Hall of Horns and Teeth at Museum of the Rockies in Bozeman, often pause at a duck-billed dinosaur skull that seems, at first glance, simply impressive in its size and preservation. But look closer. There, embedded deep in the fossilized face, is a single, broken tooth — a violent punctuation mark from 66 million years ago.
That tooth has become the centerpiece of a new study by researchers at Montana State University and the University of Alberta, offering an unusually intimate glimpse into the life — and possible death — of a dinosaur that once roamed what is now eastern Montana.
The skull belonged to Edmontosaurus, a massive plant-eater that lived alongside one of prehistory’s most formidable predators, Tyrannosaurus. The two shared the lush coastal plains of the Late Cretaceous, along with horned giants like Triceratops. It was a world of abundance and danger — and this fossil preserves a moment when those worlds collided.
Discovered in 2005 in the fossil-rich Hell Creek Formation on land managed by the Bureau of Land Management’s Miles City Field Office, the skull was remarkably complete. But its most startling feature wasn’t visible until preparation revealed a predator’s calling card lodged in its snout.
“It’s relatively rare to find a carnivore’s tooth still embedded in the dinosaur –that it was eating,” said John Scanella, the curator of paleontology at Museum of the Rockies, located on the campus of Montana State University. “Bite marks can be helpful in understanding who’s eating who.”
Finding toothy gouges and scrapes on dino bones happens occasionally with paleo finds, but this instance is unique, “because there’s a tooth embedded right in the middle of its face” he said.
Through careful comparison with known carnivorous dinosaurs from the region, researchers determined the broken tooth most closely matched that of Tyrannosaurus. CT scans performed at Bozeman Health Deaconess Hospital allowed scientists to examine how the tooth fractured and wedged into the bone, preserving a split-second of prehistoric violence.
The position of the tooth offers chilling clues. It is lodged in the nose of the Edmontosaurus, suggesting a face-to-face encounter. There are no signs of healing in the surrounding bone — meaning the animal either died from the attack or was already dead when the Tyrannosaur tore into it.
“The force required to drive a tooth into bone –and snap it– would have been tremendous,” said Scannella. “This fossil captures behavior. It’s not just a skeleton — it’s evidence of a moment.”
For decades, paleontologists have debated whether Tyrannosaurus was primarily a hunter, a scavenger, or some combination of both— “a giant land vulture” said Scanella.
While the embedded tooth does not settle that argument entirely, it strengthens the case that this apex predator engaged in powerful, close-quarters feeding — and perhaps lethal combat.
Standing before the fossil, it’s hard not to imagine the final seconds: a thunderous confrontation on an ancient floodplain, the snap of bone, the shattering of enamel. What remains is not merely a skull, but a frozen crime scene from the twilight of the dinosaurs — a reminder that even in deep time, survival was never guaranteed.
The United States Department of the Interior oversees a coordinated, science-driven paleontology program on federal lands managed by agencies such as the BLM, National Park Service, Bureau of Reclamation, and United States Fish and Wildlife Service.
Under the authority of the Paleontological Resources Preservation Act, the department works to safeguard, document, and curate fossils found on public lands. The program supports scientific research through a permitting process, fosters public education initiatives such as the Junior Paleontologist program, and ensures the responsible stewardship of the nation’s extensive fossil heritage.
Entities such as Museum of the Rockies at Montana State University, excavate these fossils under a federal permit, making both the finds and the subsequent research available to the public –and to the world.
Source: BLM press release