Tyrannosaurus rex, a dinosaur with a fearsome reputation, might actually have been a scavenger, as research has shown that its bones were unsuited to rapid running and hunting, according to Zhao Bi, a repairer of dinosaur fossils.

Zhao, director of the Paleontological Fossil Research Center at the Hubei Institute of Geosciences, said the dinosaur era was a time of great proliferation for plants known as gymnosperms, with ginkgos, cycads, pine cypresses and other gymnosperms making up most of Earth's forest vegetation at that time.

He said dinosaurs' ages can be determined by looking at slices of their fossilized bones, which reveal a structure similar to tree rings.

T.rex, a large theropod, could live to around 25 years old, while the long-necked sauropod dinosaurs could live up to 40 to 60 years or even longer, he said.

After years of studying dinosaurs and restoring dinosaur egg fossils at the Hubei Qinglong Mountain Dinosaur Egg Fossil Site Museum in Shiyan, Hubei province, Zhao has become an expert in some of the mysteries of paleontology.

Dinosaurs with different egg-laying methods have been discovered, he said.

The theropod dinosaurs laid eggs vertically in soft mud, while oviraptors laid long eggs in a radiating nest and incubated them. However, little is known about how other dinosaur eggs were laid, Zhao said.

Dinosaurs, the prehistoric reptiles that once dominated the Earth, were very diverse, he said, far exceeding the variety of reptiles on Earth today.

It can be imagined that their egg laying methods were also very diverse, with many possibilities in terms of quantity, location and method, he said.

"Now we can observe a maximum of 77 dinosaur eggs buried in the same geological layer and gathered together in Qinglongshan, and this may be a nest of eggs, perhaps produced by a dinosaur," Zhao said.

"Many dinosaur eggs from the same period were also found buried in clusters of more than 30 in other parts of the Qinglongshan site area, indicating that the dinosaurs had strong egg-laying ability."

The geological characteristics of sites where dinosaur fossils have been discovered show that there was generally more dinosaur activity near rivers and lakes, because such areas had lush vegetation that could provide sufficient food, Zhao said, adding that dinosaur fossils are often found in clusters and on a large scale, indicating that many dinosaurs lived in groups.

He said that while the study of dinosaur eggs might seem quite a boring job, it is of great scientific importance, with new discoveries sparking great interest among researchers.

Each type of dinosaur egg had an exquisite design that could help special groups of dinosaurs survive and reproduce in special environments to the greatest extent possible, he said.

Zhao said that although the internal structure of fossilized dinosaur eggs has mostly been destroyed, the macroscopic morphology of eggs, the microstructure of eggshells, and the interrelationships between eggs and the places they were buried could unravel many mysteries.

"Not only did dinosaurs evolve, but dinosaur eggs also evolved," Zhao said.

He said dinosaur eggs from different periods were clearly different, and dinosaur eggs and modern bird eggs are also different. Dinosaur eggs from Qinglongshan are also different from those discovered in the provinces of Shandong, Zhejiang, Jiangxi and Guangdong.

Repairing and studying dinosaur eggs is very exploratory, Zhao said.

"Sometimes, after finding a small clue to the eggs, and after several weeks of work, a large nest of dinosaur eggs is found that is a bit different from the dinosaur eggs we saw before," he said. "It always motivates researchers to ponder and study, and they often work hard to discover new egg species."

Some dinosaurs could fly, with fossils of Microraptors, small arboreal dinosaurs with asymmetrical flight feathers, having been discovered in Liaoning province, Zhao said.

And some dinosaurs, such as Spinosaurus, are speculated to have been able to swim, similar to crocodiles, because fossil research has found that their snouts and teeth were suitable for catching fish, and their high bone density would have helped them control their buoyancy as they hunted underwater, he added.

In 2020, the Hubei Qinglong Mountain Dinosaur Egg Fossil Group National Nature Reserve, the Chinese Academy of Sciences' Institute of Vertebrate Paleontology and Paleoanthropology and the Hubei Institute of Geosciences established a joint team of six researchers, including Zhao, to explore the mysteries of dinosaur egg fossils.

The team has cut open fossilized dinosaur eggs and used microscopes to examine their structure, and has also investigated on-site repairs and restoration and the sedimentary environment in which the fossils are found.

Zhao said Chinese researchers have an advantage, because the country's dinosaur egg fossils are the best in the world, with a large number of types completely preserved, which no other country can match. That elevated China's research on dinosaur egg fossils to an internationally advanced level by the end of the last century.

The museum is dedicated to the in situ protection and display of dinosaur egg fossils. The fossil site covers more than 7,000 square meters, with 3,204 dinosaur egg fossils restored, protected and displayed in their original positions.