A recent study shows how bird nests might have evolved from dinosaurs. Researchers discovered recently the way dinosaurs nested might have helped to the modern bird’s evolutionary success. The study shows the link between the porosity of their eggs and the connection between crocodiles and birds nesting habits.
This subject has always been under debate as nest structures are not usually preserved, not being able to stand the test of time and making it hard for scientists to determine whether dinosaurs buried their eggs or formed uncovered nests above the ground. There are many studies that cover the subject, but the paper written by Kohei Tanaka of the University of Calgary details a deep analysis of present day fossilized eggs.
Mr. Tanaka, together with his team and under the expertise of Darla Zelenitsky, dinosaur eggs and nest scientist, found a new solution to determine the nesting habits of dinosaurs. They analyzed the number and size of pores of the egg shells, comparing both fossilized eggs and modern crocodiles and birds eggs. This analysis of 30 dinosaur species and 120 species of crocodiles and birds explained how eggs were buried.
One of the clues was that the sauropods and theropods buried their eggs to incubate because the shells had high porosity. This was the only method for the oxygen and carbon dioxide to flow into and out of the egg. Some advanced species of theropods like maniraptors, had been found to have low levels of porosity in their eggs. This means that their nests were open, and probably located on the ground.
As theropods partly buried their eggs in open nests, the team concluded that the uncovered nests appeared simultaneously with the modern bird. This enabled bird-like dinosaurs to keep their eggs and nests protected from predators which might have been the success in evolution for modern day birds.
The changes from buried nests to exposed nests appeared in small carnivore dinosaurs, which are related to birds. Only future fossil discoveries will complete the gaps in dinosaur history, Tanaka explains.
Researchers hope to find out also the hatching period of the dinosaurs based on their recent discoveries.
Image source: www.gonewengland.about.com