For millions of years of existence, dinosaurs’ extinction was not as a result of their size, strength, or ferocity, but because the way their eggs were formed was a disadvantage to the species.
Today, birds have evolved into masters of incubation, but new research published in the journal Frontiers in Ecology and Evolution revealed that these egg layers were ‘inefficient’ in their ways of hatching eggs. Using advanced 3D modelling of nests and actual nest construction materials, researchers showed that dinosaurs were not capable of transferring their body heat effectively to their eggs; rather, they were primarily dependent on geothermal heat to maintain temperatures sufficient for their eggs to develop and hatch.
As a result, dinosaurs had a long incubation period of approximately six months. Given the rapidly changing nature of the Earth, the inefficient manner in which dinosaurs would have hatched eggs created huge barriers for dinosaurs to continue as a species.
Inside the experiment that tested how dinosaurs incubated eggs
Dr Tzu-Ruei Yang from Taiwan’s National Museum of Natural Science created a life-size dinosaur parent model to study how dinosaurs incubated their eggs. They made an Oviraptor that weighed 20 kilograms, and placed it in a nest that contained 30 artificial eggs.
They measured how much body heat was present in the eggs and how much actually made it to the babies using heat monitors and computer-simulated models.
The problem with the nest design
According to Frontiers in Ecology and Evolution, the way dinosaurs built their nests was not very effective in keeping their eggs warm. Today, birds will incubate their eggs by sitting directly on them. Dinosaurs would sit in the centre of a circular-shaped nest and keep themselves in the centre of the nest.
As a result, the only eggs that were kept warmest were the ones located under the parents’ chest. In contrast, the eggs located on the outer edge of the nest would be the coldest and would grow much more slowly than the other eggs.
Dinosaurs rely on the sun to help
Because the parents were unable to maintain proper warmth for all their eggs, dinosaurs relied on the sun and warm earth to carry out the heating process. The eggs were termed ‘coincubators with nature’ by researchers.
This process worked well when temperatures were high. However, the climate change caused many problems for these eggs. When cloud cover prevented sunlight from reaching them, the eggs could not maintain a constant heat source from above to incubate properly.
The three to six months waiting trap
According to the study, the time required for the eggs to successfully hatch might have also contributed to extinction. A current bird hatches in a period of weeks, whereas these dinosaurs took three to six months from the start of incubation. After the Earth experienced a massive asteroid impact resulting in catastrophic changes to its environment, dinosaurs could no longer reproduce at a rapid enough pace to survive.
Small animals such as birds and mammals were able to hatch quickly and grow rapidly, allowing them to populate and dominate while the dinosaurs continued to decline.
