That's Settled: Tyrannosaurus rex Was an Active Predator

Physical evidence of predatory behavior in Tyrannosaurus rex

Authors:

1. Robert A. DePalma II (a)
2. David A. Burnham (b)
3. Larry D. Martin (b)
4. Bruce M. Rothschild (b)
5. Peter L. Larson (c)

Affiliations:

a. Department of Paleontology, Palm Beach Museum of Natural History, Ft. Lauderdale, FL 33306

b. Division of Vertebrate Paleontology, University of Kansas Biodiversity Institute, Lawrence, KS 66045

c. Black Hills Institute of Geological Research, Inc., Hill City, SD 57745

Abstract:

Feeding strategies of the large theropod, Tyrannosaurus rex, either as a predator or a scavenger, have been a topic of debate previously compromised by lack of definitive physical evidence. Tooth drag and bone puncture marks have been documented on suggested prey items, but are often difficult to attribute to a specific theropod. Further, postmortem damage cannot be distinguished from intravital occurrences, unless evidence of healing is present. Here we report definitive evidence of predation by T. rex: a tooth crown embedded in a hadrosaurid caudal centrum, surrounded by healed bone growth. This indicates that the prey escaped and lived for some time after the injury, providing direct evidence of predatory behavior by T. rex. The two traumatically fused hadrosaur vertebrae partially enclosing a T. rex tooth were discovered in the Hell Creek Formation of South Dakota.