NEW YORK (July 15, 2013)—A fossil unearthed in South Dakota shows part of a tooth from a Tyrannosaurus rex in the tail of a duckbill dinosaur.
Some bone had grown around the tooth, which indicates the duckbill survived the attack and that it was clearly alive when the hungry T. rex bit it.
Scientists say that's strong evidence that T. rex ate live animals rather than just scavenge.
Outside experts say there was already ample evidence for that, but said the fossil is the first to show a T. rex tooth embedded in another animal's bones.
The work was published Monday by the Proceedings of the National Academy of Sciences.