Feathers, wishbones, colored eggs. If they're things you associate as only found in birds, you're wrong, says paleontologist Mark Norell. It turns out dinosaurs evolved all three, though we've only just recently learned about that last item. The discovery of fossil egg-shells in China has upended the conventional wisdom that all dino eggs were white, a belief born out of the fact that, as National Geographic reports, lizard, turtle, and crocodile eggs are white. But as a study newly published in Peer J explains, researchers now believe that a species of oviraptor named Heyuannia huangi laid blue-green eggs. While fossil eggs often end up looking brown or black, the 67 million-year-old ones found in China seemed blueish, which led scientists to try—and, as it turns out, succeed—to identify bits of colored pigments.
The two, biliverdin (blue) and protoporphyrin (red), are typically found in today's bird eggs, and the researchers speculate that the coloring may have worked as a protective camouflage. "It was a huge surprise. I couldn't believe it," says co-author Jasmina Wiemann. The findings suggest the dinosaurs were at least partially open nesting, as "colored eggs are present in most modern birds which build open nests, as the eggs are vulnerable due to periods without parental guarding." A 2015 report from CBS News on the initial findings shares another hypothesis: that male oviraptors may have provided care for the eggs, as is the case among their colored-egg modern bird counterparts. (Dinosaur eggs hatched in a potentially troublesome way.)