Fossilized dinosaur bones uncovered in Wyoming contain tooth marks that were likely made by Tyrannosaurus rex, according to research published July 15, 2026, in the open-access journal PLOS One. The study was led by Bethania C. T. Siviero of Loma Linda University and her colleagues.
Bite marks preserved in fossil bones can provide rare evidence of how prehistoric animals behaved and interacted within ancient ecosystems. In the new study, researchers examined several kinds of depressions, punctures, holes, and grooves that appeared to have been left by teeth. Using both earlier research and their own findings, the team also created a guide for interpreting possible tooth marks on fossils.
More Than 3,000 Cretaceous Bones Examined
The scientists analyzed more than 3,000 bones collected in northeastern Wyoming. The fossils date to the late Cretaceous period, roughly 72 to 66 million years ago.
Most belonged to Edmontosaurus annectens, a large plant-eating dinosaur known for its broad, duck-shaped bill.
