Biomechanics of Running Indicates Endothermy in Bipedal Dinosaurs – PLoS ONE

Although the linked paper doesn’t specifically address issues of anthropology, it’s nevertheless worth checking this to see how the researchers reached the conclusion that the amount of energy required for running meant that the two-legged dinosaurs studied would have required far more than a cold-blooded organism would have been able to cope with. Here’s the abstract:


One of the great unresolved controversies in paleobiology is whether extinct dinosaurs were endothermic, ectothermic, or some combination thereof, and when endothermy first evolved in the lineage leading to birds. Although it is well established that high, sustained growth rates and, presumably, high activity levels are ancestral for dinosaurs and pterosaurs (clade Ornithodira), other independent lines of evidence for high metabolic rates, locomotor costs, or endothermy are needed. For example, some studies have suggested that, because large dinosaurs may have been homeothermic due to their size alone and could have had heat loss problems, ectothermy would be a more plausible metabolic strategy for such animals.

Methodology/Principal Findings

Here we describe two new biomechanical approaches for reconstructing the metabolic rate of 14 extinct bipedal dinosauriforms during walking and running. These methods, well validated for extant animals, indicate that during walking and slow running the metabolic rate of at least the larger extinct dinosaurs exceeded the maximum aerobic capabilities of modern ectotherms, falling instead within the range of modern birds and mammals. Estimated metabolic rates for smaller dinosaurs are more ambiguous, but generally approach or exceed the ectotherm boundary.


Our results support the hypothesis that endothermy was widespread in at least larger non-avian dinosaurs. It was plausibly ancestral for all dinosauriforms (perhaps Ornithodira), but this is perhaps more strongly indicated by high growth rates than by locomotor costs. The polarity of the evolution of endothermy indicates that rapid growth, insulation, erect postures, and perhaps aerobic power predated advanced “avian” lung structure and high locomotor costs.

The entire paper is free to access, presumably for eternity or its nearest equivalent, whilst there’s some additional coverage from Ed Yong over at Not Exactly Rocket Science.


Citation: Pontzer H, Allen V, Hutchinson JR (2009) Biomechanics of Running Indicates Endothermy in Bipedal Dinosaurs. PLoS ONE 4(11): e7783. doi:10.1371/journal.pone.0007783

Editor: Andrew Allen Farke, Raymond M. Alf Museum of Paleontology, United States of America

Received: August 12, 2009; Accepted: October 14, 2009; Published: November 11, 2009


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