Duck-Billed Dinosaur Fossil Shows Direct Evidence of Tyrannosaur Attack
A semi-complete adult skull Edmontosaurus The Montana State Museum of the Rockies preserves a fleeting moment from the Late Cretaceous: a tyrannosaurus biting the face of a duck-billed dinosaur.
A Tyrannosaurus attack an adult Edmontosaurus. Image credit: Jenn Hall.
The damaged Edmontosaurus The skull was found in 2005 in the Hell Creek Formation in eastern Montana.
The fossil is now in the Museum of the Rockies paleontology collection and contains a telling detail: Inside its face is the tooth of a tyrannosaurus.
“While bite marks on bones are relatively common, finding an embedded tooth is extremely rare,” said Taia Wyenberg-Henzler, a doctoral student at the University of Alberta.
“The benefit of an embedded tooth, especially in a skull, is that it gives you the identity of not only who was bitten, but also who bit them.”
“This allowed us to paint a picture of what happened to this Edmontosaurusmuch like Cretaceous crime scene investigators.
Comparison of the embedded tooth with that of all carnivorous inhabitants of the Hell Creek Formation revealed that it most closely matched the teeth of Tyrannosaurus. CT scans of the skull provided more detail.
“A fossil like this is very exciting because it captures behavior: a tyrannosaurus biting the face of this duckbill,” said John Scannella, museum of the Rockies curator of paleontology.
“The skull shows no signs of healing around the Tyrannosaurus tooth, so it may have already been dead when it was bitten, or it may have died because it was bitten.”
“Looking at the way the tooth is embedded in the nose of the Edmontosaurus suggests that he met his attacker face to face, which usually happens to an animal killed by a predator,” Wyenberg-Henzler said.
“The amount of force required for a tooth to shatter into a bone also indicates the use of deadly force.”
“To me, this paints a terrifying picture of the final moments of this Edmontosaurus.”
“The eating habits of Tyrannosaurusone of the largest carnivorous animals to ever walk the Earth, has been the subject of study and debate for decades,” Dr Scannella said.
“The tooth inside Edmontosaurus the skull gives additional insight into Tyrannosaurus behavior.”
The results were published online in the journal PeerJ.
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TCA Wyenberg-Henzler and JB Scannella. 2026. Behavioral implications of an embedded Tyrannosaurus tooth and associated dental marks on an articulated skull of Edmontosaurus from the Hell Creek Formation, Montana. PeerJ 14:e20796; doi: 10.7717/peerj.20796
