Tyrannosaurus was not a fast runner review: Pt. 2

Hutchinson and Garcia used data from extant animals to help support their claim. They looked at the muscle anatomy of different animal’s hips, knees, ankles, and toes in order to come up with a sufficient comparison to Tyrannosaurus. Also due to fossilized footprints they had data present for small tyrannosaurs. Other animals that were used in comparison include: alligators, chickens, and the extinct Colelophysis. In comparing the muscle percent of the alligator and the chicken they found that the chicken has a larger percent of muscle mass per body mass than alligators which allow them to run faster. This is due to scaling principles predicting that animals of larger body mass have a more restricted locomotor performance. In order for the Tyrannosaurus to be a fast runner it would need enough muscle mass to support its body the authors argue. The authors calculated that the dinosaur would need about 43% of its body mass to be muscles in each leg alone in order to be a fast runner.