Reconstructing a dinosaur nest to solve a 70-million-year-old mystery
It has always been unclear how Oviraptor dinosaurs, which are bird-like but flightless dinosaurs, hatch their eggs.
Like crocodiles or birds?
A new study published on Science Daily, citing the journal Frontiers in Ecology & Evolution, has revealed new information about the phenomenon by examining the nest-building behavior and hatching patterns of oviraptors. Researchers in Taiwan said they combined heat transfer simulations with practical experiments to better understand how these dinosaurs incubated their eggs. They also compared their results to modern bird incubation. They reported that to do this, they built a life-size model of an Oviraptor dinosaur and a realistic nest to test how heat is transferred through the eggs.
An illustration of dinosaurs
Dr. Tzu-Rui Yang, the study’s lead researcher and curator of the Vertebrate Paleontology Department at the National Museum of Natural Science in Taiwan, explained that the experiment showed the difference in oviraptor egg hatching patterns, noting that this difference resulted from the relative position of the adult female incubating the eggs. The study's lead researcher, Chun-Yoo Su, added that, furthermore, an estimate was reached for the incubation efficiency of Oviraptor eggs, which is much lower than the incubation efficiency of modern bird eggs.
In addition, the model was based on "Hua'iania Huanghe," a type of oviraptor that lived between 70 and 66 million years ago in what is now China. This dinosaur was about 1.5 meters long and weighed about 20 kilograms. It built semi-open nests arranged in multiple rings of eggs.
To reconstruct this organism, the researchers built the torso using polystyrene foam and a wooden frame, then added cotton, bubble wrap, and fabric to mimic soft tissue. The eggs were made from casting resin. In the experiments, two sets of eggs were arranged in double rings to mimic fossil evidence.
The research team also tested how both the presence of adults and environmental conditions affect egg temperatures and hatching outcomes. In cold conditions, and in the presence of an adult incubator, temperatures in the outer ring of the eggs varied by up to 6 degrees Celsius. These differences can also lead to asynchronous hatching, where eggs hatch in the same nest at different times. In warmer environments, this variation decreased to about 0.6°C. This suggests that in warmer climates, sunlight may have helped to standardize temperatures and influence hatching patterns.
The researchers also compared the incubation of oviraptor eggs to that of modern birds, as most birds rely on thermal contact incubation, where the adult bird sits directly on its eggs and provides them with heat. For this method to work, the adult bird must touch all the eggs, be the main source of heat, and maintain a stable temperature.
Which is better?
It is worth noting that the oviraptor was likely unable to meet these requirements. The ring-shaped arrangement of its eggs meant that an adult bird could not have touched each egg at once. Therefore, it is likely that these dinosaurs and environmental heat were working together, making them common incubators.
Although this method was less efficient than that of modern birds, it was probably suitable for their nesting style, which appears to have shifted from buried nests to semi-open nests. In conclusion, modern birds are not better at incubating eggs. Rather, birds that live today, including ovariaptors, employ a completely different method of incubation, or more accurately, of caring for their young. There is no better or worse style; it ultimately depends on the environment.
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