Fossilized eggs reveal the past's secrets.

Eggs have been laid on land by birds, reptiles, dinosaurs and a few oddball mammals for more than 200 million years. Humans have been using some of these eggs as a nutritious source of food and their shells as bowls, bottles and jewelry for most of our history on the planet. Fossilized eggshells are a fascinating source of information, illuminating the behavior and diet of ancient creatures, detailing changes in climate and revealing how our prehistoric relatives lived and communicated. Dinosaur body temperatureDid dinosaur blood run cold, like a lizard, or warm, like a bird? An analysis of fossilized dinosaur egg shells suggests it was the latter.

By looking at the order of oxygen and carbon atoms in the fossilized egg shells, researchers were able to calculate a dinosaur mom’s internal body temperature. The research indicates that unlike reptiles, which rely on heat from the environment, dinosaurs were capable of internally generating heat – more like birds.