Taiwanese researchers built a life-size model of an oviraptor nest to investigate how these dinosaurs incubated their eggs. Their experiments indicate a hybrid method involving parental warmth and sunlight, differing from modern birds. This approach explains uneven heating and asynchronous hatching in nests.
Researchers from Taiwan's National Museum of Natural Science conducted experiments to understand oviraptor nesting behavior, as detailed in a study published in Frontiers in Ecology and Evolution. They recreated a nest based on Heyuannia huangi, an oviraptor species from 70 to 66 million years ago in present-day China. The dinosaur measured about 1.5 meters long and weighed around 20kg, with eggs arranged in double rings in semi-open nests. The model used polystyrene foam for the torso, a wooden frame, cotton, bubble paper, and fabric for tissues, plus resin eggs mimicking fossils. Heat transfer simulations and physical tests assessed temperature variations under different conditions with and without the brooding adult present. In colder settings, outer ring eggs showed up to 6°C differences, potentially causing eggs in the same nest to hatch at staggered times. Warmer environments reduced this to 0.6°C, suggesting sunlight's role in evening out heat. Senior author Dr. Tzu-Ruei Yang stated, 'We show the difference in oviraptor hatching patterns was induced by the relative position of the incubating adult to the eggs.' First author Chun-Yu Su added, 'We obtained an estimate of the incubation efficiency of oviraptors, which is much lower than that of modern birds.' The ring arrangement prevented full contact incubation like in birds, leading to a co-incubation with environmental heat. Yang noted, 'Heat from the sun likely mattered much more than heat from the soil.' The team cautions that results use modern conditions, unlike the Late Cretaceous, and oviraptors probably had longer incubation periods. This work highlights distinct brooding strategies suited to environments.