Birds Inherited Their Nesting Habits From Dinosaurs

Advanced theropods like the maniraptorans, featured high porosity eggshells, suggesting that they laid and incubated their eggs in open nests in the similar fashion as their most closely related living birds.

A research by University of Calgary PhD student sheds light on how dinosaur nesting styles evolved potentially explaining the evolutionary success of current brooding birds.

It’s tough to determine habits of animals from millions of years ago, but scientists found that birds inherited their nesting habits from dinosaurs. In the past, this lack of data has made working with dinosaur eggs and eggshells extremely hard to determine how dinosaurs built their nests and how the eggs were incubated for hatching young.

For the past number of years, researchers have been trying to figure out how dinosaurs incubated eggs.

“We were surprised that although previous studies on the eggs of oviraptorids suggested they were buried, our results reveal that their eggs were exposed similar to modern bird nests”, said Tanaka.

According to Sciencemag, Luis Chiappe, a vertebrate paleontologist at the Natural History Museum of Los Angeles County in California said that the findings are in line up other studies that suggest that some birdlike dinosaurs were warm-blooded, which would have enabled them to incubate eggs in an open nest.

The team even said that they found evidence of theropods partly burying their eggs which is why they concluded that it was only the modern birds with which open nest patterns that left eggs fully exposed begun. Study co-researcher Darla Zelenitsky, an assistant professor of paleontology at the University of Calgary in Canada said in a statement. Others built open nests on the ground, like today’s birds.

So to conduct their research, Mr. Tanaka and the research team came up with a novel solution: they compared the pores, or holes, in preserved dinosaur eggshells with those of birds and crocodiles. Given that a majority of dinosaurs – including sauropods, ornithischians, and primitive theropods – laid high porosity eggs in order to help the distribution of carbon dioxide and oxygen and simultaneously allow the escape of water vapor, it is most probable that they buried their eggs like crocodiles do. They were placed within the ground, covered by mud and vegetation, which resulted in more porous eggs.

These dinosaur shells are being studied at the University of Calgary. “However, some of the microscopic features of the eggshell, such as porosity, are preserved, and can be used to infer the types of nests in dinosaurs in the absence complete nests”.

Tanaka also explains: “Fossil eggs are more challenging to study because fossil specimens are often incomplete”. A switch from buried nests to open nesting and brooding would ensure that the eggs of advanced theropods (including birds) would be safe from ground predators, which may have played a large role in their evolutionary success. Moreover, the vegetation or the dirt covering the eggs provided an optimal temperature for the newborn.

The nesting habits of dinosaurs have baffled experts since forever, mostly due to the fact that intact dinosaur eggs and nests are a very rare encounter.