Why Do Birds Have Colorful Eggs? Because They're Dinosaurs

Dinosaurs ugly colored eggs. Birds lay colorful eggs. You do the maths.

But really though: A study from the last year found that oviraptors, a dinosaur of the late Cretaceous period, ugly blue-green eggs, containing the same pigments as modern bird eggs. This made-up scientists wonder whether birds evolved colored eggs on their own, or whether they inherited egg color from an ancient ancestor. A new badysis finds that egg color seems to have evolved only once, and that birds maintain this trait from their theropod days.

"Here we are able to show you a lot of things that are unique in their history," Mark Norell, division chair of paleontology at the American Museum of Natural History, told Gizmodo.

Researchers previously found evidence that oviraptor dinosaurs had pigment in their eggs just like birds do. They discovered this by slicing off a piece of a dinosaur egg and putting it through a molecule-identifying mbad spectrometer machine. But for this recent study, two of the first papers, along with Norell, we have been trying to badyze the fossils.

"Jasmina Wiemann, Yale graduate student, told Gizmodo.

The team sampled 19 eggshells from archosaurs, the group that includes crocodilians and dinosaurs, both extinct and living (including chickens). Rather than sampling pieces of eggs, they used Raman spectroscopy-hitting the samples with a laser and detecting the wavelengths of the light that bounces back. The colors of the scattered light reveal the types of molecules present in the eggs.

Both pigments found in today's bird eggs, red-brown protoporphyrin IX and blue-green biliverdin, also came from the family (live bird ancestors), which had spotted and speckled patterns like birds eggs. Pigment did not occur in the crocodilian, sauropod, or ornithischian eggs (the other two dinosaur groups), according to the study published in Nature. By Mapping the Distribution of Egg Coloring on the Evolutionary Tree and Determining which eggs were colored and which were not. The researchers found their data supported by the hypothesis that egg color evolved only once.

But why? Wiemann and Norell both hypothesized that the emergence of egg color stemmed from theropods no longer laying down their eggs in underground or covered nests. An open nest means that it was better to have eggs in the box, or perhaps to recognize them in their own eggs. One animal coloring expert not involved in the study, professor Mary Caswell Stoddard at Princeton, thought the research would ignite conversations about dinosaur behavior.

"The exciting discovery that pigmented eggshells evolved in nonavian theropod dinosaurs will change the way we think about dinosaur nesting and incubation behavior," she said. "What were the functions of various eggshell colors and patterns? Were they for camouflage? Thermoregulation? Or, in some parasitic birds, to mimic the appearance of a host's eggs? These are just a few of the questions of behavioral ecologists and paleontologists will be asking in the years to come. "

This is also what we are looking for in the future, which has been colored with eggs and which does not correspond to egg color. The researchers will now need a larger sample of eggshells to badysis.

Aim, once again, birds are living dinosaurs. This result is yet another example demonstrating that.