Tyrannosaurus en pointe: Allometry minimized rotational inertia of large carnivorous dinosaurs

Donald M. Henderson, Eric Snively

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


Theropod dinosaurs attained the largest body sizes among terrestrial predators, and were also unique in being exclusively bipedal. With only two limbs for propulsion and balance, theropods would have been greatly constrained in their locomotor performance at large body size. Using three-dimensional restorations of the axial bodies and limbs of 12 theropod dinosaurs, and determining their rotational inertias (RIs) about a vertical axis, we show that these animals expressed a pattern of phyletic size increase that minimized the increase in RI associated with increases in body size. By contrast, the RI of six quadrupedal, carnivorous archosaurs exhibited changes in body proportions that were closer to those predicted by isometry. Correlations of low RI with high agility in lizards suggest that large theropods, with low relative RI, could engage in activities requiring higher agility than would be possible with isometric scaling.

Original languageEnglish
Pages (from-to)S57-S60
JournalProceedings of the Royal Society B: Biological Sciences
Issue numberSUPPL. 3
StatePublished - 7 Feb 2004
Externally publishedYes


  • Archosaurs
  • Biomechanics
  • Rotational inertia
  • Theropods
  • Turning performance


Dive into the research topics of 'Tyrannosaurus en pointe: Allometry minimized rotational inertia of large carnivorous dinosaurs'. Together they form a unique fingerprint.

Cite this