Jurassic Park made T. rex attacks terrifying; now, a 66-million-year-old fossil shows one may have happened almost exactly like that

If you grew up rewatching the scene where the Jurassic Park T. rex snaps its jaws inches from a Jeep, you already have a picture of what a tyrannosaur attack looks like: sudden, brutal, and face-first. A new study published in the journal PeerJ says scientists have found an actual fossil that lines up with almost that exact scenario, minus the four-wheeled vehicle.

It happened about 66 million years ago in what is now Montana, leaving behind one very unlucky dinosaur, according to an official release from Montana State University.

A tooth stuck in the face tells the whole story
In 2005, researchers discovered a nearly complete skull of Edmontosaurus, a large, plant-eating, duck-billed dinosaur, on land managed by the Bureau of Land Management in Montana’s Hell Creek Formation. The skull sat in the collection at Montana State University's Museum of the Rockies when researchers turned their attention to what made the skull so odd: a broken tooth jammed into the animal’s nasal bone, a tooth that did not belong to the Edmontosaurus itself.


In the PeerJ study titled ‘Behavioral implications of an embedded tyrannosaurid tooth and associated tooth marks on an articulated skull of Edmontosaurus from the Hell Creek Formation, Montana’ that embedded tooth is described as belonging to a Tyrannosaurus. Today, the skull is displayed in the museum’s Hall of Horns and Teeth and was the subject of an investigation led by University of Alberta doctoral student Taia Wyenberg-Henzler and Museum of the Rockies curator John Scannella.

Why is one broken tooth such a big deal
Bite marks on dinosaur bones are fairly common, but an actual tooth preserved inside the bone is exceedingly rare, according to the PeerJ study. The team used CT scans to determine the location and angle of the tooth inside the skull, and then size, curvature, and denticle pattern (the tiny serrations along the edge of a tooth) were compared to those of teeth from all known meat-eating dinosaurs that shared the same rock layer as Edmontosaurus.

In the study’s CT work, the tooth sat in the nose of the Edmontosaurus skull at a steep angle, and the authors argue that such placement is difficult to reconcile with a glancing nip. They also note that the broken tip and associated marks fit a bite delivered with enough force to lodge, fracture, and leave the tooth behind rather than simply scrape the bone.

In the same study, the comparison pointed to one suspect: an adult Tyrannosaurus, not a juvenile tyrannosaur and not the smaller, controversial dinosaur known as Nanotyrannus. The tooth landed close to the front of the animal’s face, so the researchers suggest the bite was from something close to a direct, front-on strike, closer to the classic movie-monster image than most fossil evidence tends to be.

Was it a hunt or a scavenged meal
There is no evidence of healing around the wound, said the authors. That leaves two possibilities: either the tyrannosaur attacked and killed the animal, or the Edmontosaurus was already dead, and the tyrannosaur was scavenging when its tooth snapped off. Bone alone doesn’t always make a clear distinction between a kill and a meal already on the ground, so the researchers didn’t go so far as to call this a confirmed predatory attack.

What the fossil does confirm is that it was a violent blow. A 2017 study, ‘The Biomechanics Behind Extreme Osteophagy in Tyrannosaurus rex,’ in Scientific Reports concluded that an adult Tyrannosaurus could generate bite forces of around 8,000 pounds, enough to crush bone like a hyena, not just puncture soft tissue like most reptiles. A tooth that can embed itself in another dinosaur’s skull and break off fits the bill.

The 2017 paper examined seven adult T. rex skulls, spanning much of the known size range for the species, and estimated maximum bite forces between 18,014 and 34,522 N, or about 4,050 to 7,761 lb. It also found tooth forces up to 2,974 MPa and concluded that those forces exceeded the shear strength of cortical bone for at least 25 mm of tooth crown height, explaining how the predator could effectively crack and fragment bone.

Why this matters beyond the fossil case
The evidence has mostly been indirect, and scientists have debated the eating habits of Tyrannosaurus for decades, according to a release from Montana State University. This skull is unusual because not only does it show damage, but also an interaction preserved in situ, tooth and all.

As Taia Wyenberg-Henzler said in the Montana State University release, an embedded tooth can tell you who was bitten and who did the biting, which is so rare that the researchers likened their work to old-fashioned crime scene reconstruction.

If you think of a T. rex attack as something you see in the movies, this is about as close to reality as paleontology has gotten. While the fossil alone can’t settle the predator-versus-scavenger debate, it does provide physical evidence for the idea that Tyrannosaurus was capable of the kind of powerful, face-on bite pop culture has been depicting since Jurassic Park hit theatres more than three decades ago.