Scientist Reveals Dinosaurs were Warm-Blooded Like Birds and Mammals

Dinosaurs once roamed across our planet, thriving in lush forests, deep seas and vast plains. Now, scientists have discovered a little more about these large animals. It turns out that the researchers have uncovered evidence that indicates that dinosaurs were warm-blooded like birds and mammals rather than cold-blooded like reptiles, as commonly believed.

"Some point out that a large saltwater crocodile can achieve a body temperature above 30 degrees C by basking in the sun, and it can maintain the high temperature overnight simply by being large and slow to change temperature," said Roger Seymour, the author of the paper, in a news release. "They say that large, cold-blooded dinosaurs could have done the same and enjoyed a warm body temperature without the need to generate the heat in their own cells through burning food energy like warm-blooded animals."

In order to examine whether or not dinosaurs could have survived by soaking up their heat from only the sun, Seymour examined how much muscular power could be produced by a crocodile-like dinosaur compared to a mammal-like dinosaur of the same size. He drew from blood and muscle lactate measurements collected by his collaborators and found that a 200 kg crocodile can only produce about 14 percent of the muscle power of a mammal at peak exercise. This fraction seems to decrease at larger body sizes.

"The results further show that cold-blooded crocodiles lack not only the absolute power for exercise, but also the endurance that are evident in warm-blooded mammals," said Seymour. "So despite the impression that crocodiles are extremely powerful animals, a crocodile-like dinosaur could not compete well against a mammal-like dinosaur of the same size."

This particular finding is important to note. Dinosaurs dominated the ecosystem throughout the Mesozoic period. They preyed on smaller mammals and other dinosaurs, which means that they would have had to have the proper muscular endurance and strength to chase down their prey. Because of this, it's very likely that dinosaurs were also warm-blooded.

These findings add to Seymour's earlier work on blood flow to dinosaur leg bones. The previous study revealed that dinosaurs were more active that mammals. Added to this newest research, it looks likely that, in fact, dinosaurs shared more in common with mammals and birds than we realized.

The findings are published in the journal PLOS One.