Dinosaurs Were Neither Cold Nor Warm Blooded, Study Says

Dinosaurs may not have been cold-blooded like modern reptiles or warm-blooded like mammals and birds — instead, they may have dominated the planet for 135 million years with blood that ran neither hot nor cold, but was a kind of in-between that's rare nowadays, researchers say.

Modern reptiles such as lizards, snakes and turtles are cold-blooded or ectothermic, meaning their body temperatures depend on their environments. Birds and mammals, on the other hand, are warm-blooded, meaning they control their own body temperatures, attempting to keep them at a safe constant — in the case of humans, at about 98.6 degrees Fahrenheit. Read more...