Dinosaurs Likely Weren't Either Warm or Cold Blooded, Could've Been Both

New research may settle the debate of whether dinosaurs were warm or cold blooded by concluding that the question should not be an either-or.

According to The Washington Post, the new study, published in the journal Nature Communications, suggested dinosaurs were both. The research is based on fossilized eggshells previously discovered in Argentina and Mongolia.

The researchers analyzed the eggs' chemistry to try and determine their temperatures when they formed.

"This technique tells you about the internal body temperature of the female dinosaur when she was ovulating," study co-author Aradhna Tripati, a geologist at the University of California, Los Angeles, said in a press release from the National Science Foundation (NSF), which funded the study. "This presents the first direct measurements of theropod body temperatures."

Whether dinosaurs were warm or cold blooded has been a debate for about a century and a half and determining such information could also help with understanding their levels of activity.

"These scientists used a relatively new isotope analysis technique on fossil eggshells to investigate thermal regulation in non-avian dinosaurs," Rich Lane, program director for NSF's Division of Earth Sciences, said in the release. "Comparing the results to modern birds sheds light on the evolution of this trait."

The researchers concluded the question is not so simple as being either one or the other.

"It's important to realize that there's actually a whole sliding scale of physiology," study lead author Robert Eagle, a researcher at UCLA, told The Post. "So the real question is where dinosaurs fell on that spectrum.

"We can't take just body temperature and jump to the conclusion that they weren't cold blooded," he said, "but combined with other data, it's consistent with them having some kind of intermediary metabolism. This suggests that maybe they were warm blooded, but hadn't developed the high level of temperature regulation seen in mammals and birds today. They were kind of part way to evolving endothermy."