The Biomechanics Behind Extreme Osteophagy in Tyrannosaurus rex
Paul M. Gignac & Gregory M. Erickson
Scientific Reports 7, Article number: 2012 (2017)
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Biomechanics Palaeontology
Received: 25 November 2016 Accepted: 07 April 2017
Published online: 17 May 2017
Abstract
Most carnivorous mammals can pulverize skeletal elements by generating tooth pressures between occluding teeth that exceed cortical bone shear strength, thereby permitting access to marrow and phosphatic salts. Conversely, carnivorous reptiles have non-occluding dentitions that engender negligible bone damage during feeding. As a result, most reptilian predators can only consume bones in their entirety. Nevertheless, North American tyrannosaurids, including the giant (13 metres [m]) theropod dinosaur Tyrannosaurus rex stand out for habitually biting deeply into bones, pulverizing and digesting them. How this mammal-like capacity was possible, absent dental occlusion, is unknown. Here we analyzed T. rex feeding behaviour from trace evidence, estimated bite forces and tooth pressures, and studied tooth-bone contacts to provide the answer. We show that bone pulverization was made possible through a combination of: (1) prodigious bite forces (8,526–34,522 newtons [N]) and tooth pressures (718–2,974 megapascals [MPa]) promoting crack propagation in bones, (2) tooth form and dental arcade configurations that concentrated shear stresses, and (3) repetitive, localized biting. Collectively, these capacities and behaviors allowed T. rex to finely fragment bones and more fully exploit large dinosaur carcasses for sustenance relative to competing carnivores.
Acknowledgements
We thank P. Larson and staff at the BHI, P. Makovicky and the FMNH, M. Norell, C. Mehling, and the AMNH, and K. Cramer at CarmikeTM Cinemas (which temporarily exhibited BHI 4100) for access to specimens; A. Andersen and Virtual Surfaces, Inc. for allowing us access to surface-scan files of BHI 3033; D. Kay and S. Kuhn-Hendricks for assistance in specimen measurements; J. Brueggen and K. Vliet for assistance accessing citations; K. Chin for early discussions about this subject; M. Hill and H. Towbin for technical assistance with CT scanning; H. O’Brien and A. Watanabe for assistance with 3-D rendering software. PMG was supported by the National Science Foundation (no. 1450850) and Oklahoma State University Center for Health Sciences. GME was supported by a grant from the Committee for Research and Exploration of the National Geographic Society (no. 7026–01) and Florida State University.
Author information
Affiliations
Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, 74107-1898, USA
Paul M. Gignac
Department of Biological Science, Florida State University, Tallahassee, Florida, 32306-4295, USA
Gregory M. Erickson
Contributions
P.M.G. and G.M.E. designed the study and collected the data. P.M.G. performed the biomechanical analyses and developed the figures. P.M.G. and G.M.E. wrote the paper. The authors have no conflicting financial interests in the content or techniques discussed in this manuscript.
Competing Interests
The authors declare that they have no competing interests.
Corresponding author
Correspondence to Paul M. Gignac.
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