SCIENCE / MEDICINE : Were Dinosaurs Peppier Than Usually Portrayed?

A study of human-sized turtles suggests dinosaurs were able to regulate their body temperatures in warm and cool climates much like large mammals, researchers reported in the journal Nature. The study has added to a growing body of evidence that dinosaurs were not the sluggish, lumbering, cold-blooded reptiles depicted in Godzilla movies, but lively, sociable beasts that acted much like animals do today.

Researchers from Drexel and Purdue universities said the physiology of the reptilian leatherback turtles--which inhabit both hemispheres from the tropics to the Arctic circles--probably explains how dinosaurs were able to survive in warm and icy conditions over 65 million years ago.

The reptilian leatherbacks, which are usually about six feet long but have been known to reach nine feet in length and weigh up to 2,000 pounds, are able to withstand freezing water because of their size and by regulating blood flow to conserve energy, the scientists said.

Studies of living leatherbacks indicate the massive reptiles are able to control their internal thermostat by controlling their blood flow, which would enable them to remain active. When the turtles are in colder waters, their blood vessels contract away from their extremities, conserving energy.