Evidence indicates dinos were probably warm-blooded.

Byline: ANI

Washington, November 11 (ANI): In a new study, a team of scientists has found strong evidence that many dinosaur species were probably warm-blooded.

Herman Pontzer, assistant professor of anthropology in Arts and Sciences, worked with colleagues John R. Hutchinson and Vivian Allen from the Structure and Motion Laboratory at the Royal Veterinary College, UK, to bring a combination of simple measurements, rigorous computer modeling techniques and their knowledge of physiology in present-day animals to bear in a new study on this hot topic.

Using their combined experience, the authors set out to determine whether a variety of dinosaurs and closely related extinct animals were endothermic (warm-blooded) or ectothermic (cold-blooded), and when, where and how often in the dinosaur family tree this important trait may have evolved.

"I work on the evolution of human locomotion, using studies of living humans and other animals to figure out the gait and efficiency of our earliest fossil ancestors. When I realized this approach could be applied to the dinosaur record, I contacted John Hutchinson, an expert on dinosaur locomotion, and suggested we collaborate on this project," said Pontzer.

"Our results provide strong evidence that many dinosaur species were probably warm-blooded. The debate on this issue will no doubt continue, but we hope our study will add a useful new line of evidence," he added.

Studies of present-day animals have shown that endothermic animals are able to sustain much higher rates of energy use than ectothermic animals can.

Following this observation, the researches reasoned that if the energy cost of walking and running could be estimated in dinosaurs, the results might show whether these extinct species were warm or cold-blooded.

Pontzer and colleagues examined recent anatomical models of 13 extinct dinosaur species, using detailed measurements of the fossilized bony levers that limb muscles attached to.

From this, the authors were able to reconstruct the mechanical advantage of the limb muscles and calculate the active muscle volume required for each dinosaur to walk or run at different speeds.

The cost of activating this muscle was then compared to similar costs in present-day endothermic and ectothermic animals.

The results of both the simple and complex method were in very close agreement.

Based on the energy they consumed when moving, many dinosaurs were probably endothermic, athletic animals because their energy requirements during walking and running were too high for cold-blooded animals to produce. (ANI)

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