Scientists recreated a life-sized oviraptor and nest to investigate how these bird-like dinosaurs hatched their eggs.
How exactly did oviraptors, bird-like but flightless dinosaurs, hatch their eggs? Scientists have long debated whether these dinosaurs relied mainly on heat from the environment, similar to crocodiles and turtles, or used body warmth from a brooding adult like modern birds. A new study published today in Frontiers in Ecology and Evolution takes a closer look at this mystery.
Researchers in Taiwan analyzed oviraptor brooding behavior and egg hatching patterns. They also ran heat transfer simulations on oviraptor egg clutches and compared the results with incubation efficiency in modern birds. To test their ideas, the team created a life-sized experimental setup using a model oviraptor and artificial eggs designed to mimic the real ones.
“We show the difference in oviraptor hatching patterns was induced by the relative position of the incubating adult to the eggs,” said senior author Dr. Tzu-Ruei Yang, an associate curator of vertebrate paleontology at Taiwan’s National Museum of Natural Science.
“Moreover, we obtained an estimate of the incubation efficiency of oviraptors, which is much lower than that of modern birds,” added first author Chun-Yu Su, who attended Washington High School in Taichung when the research was conducted.
Recreating a Dinosaur Nest
The team based their reconstruction on Heyuannia huangi, a species of oviraptor that lived roughly 70 to 66 million years ago in what is now China. This dinosaur was estimated to be about 1.5 meters long and weigh around 20kg. It built semi-open nests containing multiple rings of eggs.
To recreate the brooding dinosaur, researchers constructed a trunk using polystyrene foam and wood for the internal frame. Cotton, bubble paper, and cloth were added to simulate soft tissues. The eggs themselves were produced from casting resin.
Two experimental clutches were arranged in double rings, reflecting the structure seen in fossilized oviraptor nests. This unusual layout meant that not every egg could come into direct contact with the brooding adult.
“Part of the difficulty lies in reconstructing oviraptor incubation realistically,” said Su. “For example, their eggs are unlike those of any living species, so we invented the resin eggs to approximate real oviraptor eggs as best as we could.”
Temperature Differences in Dinosaur Egg Clutches
The experiments explored how the presence of a brooding adult and different environmental temperatures could influence egg warming and hatching patterns.
In colder conditions with an adult attending the nest, eggs located in the outer ring showed temperature differences of up to 6°C. Such variation could cause asynchronous hatching, where eggs from the same clutch emerge at different times.
Under warmer conditions, the outer ring eggs showed only about a 0.6°C temperature difference. This suggests that oviraptors living in warmer climates may have experienced different hatching patterns because sunlight could serve as an additional heat source.
“It’s unlikely that large dinosaurs sat atop their clutches. Supposedly, they used the heat of the sun or soil to hatch their eggs, like turtles. Since oviraptor clutches are open to the air, heat from the sun likely mattered much more than heat from the soil,” Yang explained.
Comparing Dinosaur and Bird Incubation
The researchers also compared how efficiently oviraptors incubated their eggs relative to modern birds.
Most birds rely on thermoregulatory contact incubation (TCI), where a parent sits directly on the eggs and transfers body heat to them. For this system to work, three conditions must be met. The adult must touch every egg, act as the primary heat source, and keep all eggs within a narrow temperature range.
Oviraptors likely could not meet these requirements. Their circular egg arrangement prevented full contact between the adult and every egg in the clutch.
“Oviraptors may not have been able to conduct TCI as modern birds do,” said Su. Instead, these dinosaurs and the sun may have been co-incubators, creating a less efficient incubation method compared with modern birds. Still, this combination of parental warmth and environmental heat may have been a practical adaptation as nests evolved from buried structures to semi-open ones.
“Modern birds aren’t ‘better’ at hatching eggs. Instead, birds living today and oviraptors have a very different way of incubation or, more specifically, brooding,” Yang pointed out. “Nothing is better or worse. It just depends on the environment.”
New Insights Into Dinosaur Parenting
The researchers noted that their findings apply specifically to the reconstructed nest used in the experiment. Another limitation is that today’s climate differs from conditions during the Late Cretaceous period, which could influence the results. Oviraptors also appear to have had longer incubation periods than modern birds.
Even so, the study provides valuable insight into how these dinosaurs may have cared for their eggs. By combining physical experiments with heat transfer simulations, the research offers a new way to study dinosaur reproduction.
“It also truly is an encouragement for all students, especially in Taiwan,” concluded Yang. “There are no dinosaur fossils in Taiwan, but that does not mean that we cannot do dinosaur studies.”
Reference: “Heat transfer in a realistic clutch reveals a lower efficiency in incubation of oviraptorid dinosaurs than of modern birds” by Chun-Yu Su, Jun-Yang Liao, Hsiao-Jou Wu, Kuan-Yu Chou, Ching Chen, Ming-Tsang Lee and Tzu-Ruei Yang, 21 January 2026, Frontiers in Ecology and Evolution.
DOI: 10.3389/fevo.2026.1351288
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