For 150 years scientists have debated whether dinosaurs were fast predators like what is depicted in the movies, or had low metabolic rates that caused them to sluggish like today's crocodiles. New research may finally be able to answer these questions.

A team of scientists found some dinosaurs had the ability to elevate their body temperatures using environmental heat sources such as the sun, UCLA reported. They also found evidence that dinosaurs were able to move much quicker than today's alligators and crocodiles. On the other hand, evidence suggests dinosaurs had lower body temperatures and were less active than their only living relatives, birds. To make their findings, the researchers looked at fossilized dinosaur eggshells from Argentina and Mongolia. The chemistry of the ancient shells revealed the temperature at which the eggs formed.

"This technique tells you about the internal body temperature of the female dinosaur when she was ovulating," said Aradhna Tripati, a co-author of the study and a UCLA assistant professor of geology, geochemistry and geobiology. "This presents the first the direct measurements of theropod body temperatures."

The 80 million-year-old titanosaur sauropod eggshells from Argentina and the 75 million-year-old oviraptorid theropod eggs from Mongolia's Gobi desert provided key insights into these dinosaurs' body temperatures. The team found large Sauropods had body temperatures of approximately 100 degrees Fahrenheit while smaller oviraptorid theropods had temperatures of about 90 degrees. The debate as to whether dinosaurs were warm-blooded or cold-blooded has been in full swing since the 19th century, and this information suggests the answer is somewhere in between.

"The temperatures we measured suggest that at least some dinosaurs were not fully endotherms like modern birds," said Robert Eagle, a researcher in the department of earth, planetary and space sciences in the UCLA College. "They may have been intermediate-somewhere between modern alligators and crocodiles and modern birds; certainly that's the implication for the oviraptorid theropods.  This could mean that they produced some heat internally and elevated their body temperatures above that of the environment but didn't maintain as high temperatures or as controlled temperatures as modern birds. If dinosaurs were at least endothermic to a degree, they had more capacity to run around searching for food than an alligator would."

The findings were published in a recent edition of the journal Nature Communications.