Dinosaur researcher and VTuber, Kochirui, has published a new theory on the evolution of dinosaur digestive strategies in the American academic journal Paleobiology.
Susumu Kochirui is the persona of Ryuji Takasaki, an assistant professor at University Okayama of Science, when he works as a VTuber. He explains the latest research in paleontology, mainly focusing on dinosaurs, to the general public on YouTube and X. As of July 2026, his YouTube channel has 17,000 subscribers and his X followers number 9,200.
The internal organs of dinosaurs, such as their stomachs, are rarely preserved as fossils, making it difficult to understand their digestive mechanisms. This study focused on the shape of “gastroliths,” which are found alongside fossils. The researchers analyzed the shape of the gastroliths, diet, and stomach muscle mass of 104 individuals from 46 species of birds and crocodiles. The results showed that individuals with rounded gastroliths had stomachs with high muscle mass and tended to be herbivorous, while individuals with angular gastroliths had less muscle mass and tended to be carnivorous. The study also demonstrated that the shape of the gastrolith could identify diet with approximately 70% accuracy.
When this method was applied to the dinosaur fossil record, it was discovered that many toothless theropods (the group leading to birds) had rounded gastroliths. This suggests that they may have digested food in a muscular stomach, similar to how modern birds grind food in their gizzards. On the other hand, other herbivorous dinosaurs such as Psittacosaurus, a distant relative of Triceratops, and sauropods often had angular gastroliths, suggesting they may have had different digestive strategies, such as teeth, jaws, or fermentation in the intestines.
A video explaining the research details will be released on YouTube on July 24th. A live stream commemorating the paper’s publication is also planned for the following day, the 25th.
This article is an English translation of an original Japanese article, translated by the Mogura VR editorial team.
Reference
https://prtimes.jp/main/html/rd/p/000000002.000169782.html
