Physiology of dinosaurs way as sauropods. The pachycephalosaurs had small heads and weak jaws and teeth, but their lack of large digestive systems suggests a different diet, possibly fruits, seeds, or young shoots, which would have been more nutritious to them than leaves. On the other hand, ornithopods such as "Hypsilophodon", "Iguanodon" and various hadrosaurs had horny beaks for snipping off vegetation and jaws and teeth that were well-adapted for chewing. The horned ceratopsians had similar mechanisms. It has often been suggested that at least some dinosaurs used swallowed stones, known as gastroliths, to aid digestion by grinding their food in muscular gizzards,
Chased by Dinosaurs Chased by Dinosaurs Chased by Dinosaurs is a five-episode spin-off of the BBC program "Walking with Dinosaurs" which originally aird on BBC One during Christmas 2002 and November 2003. In a departure from the series usual format, these specials feature zoologist Nigel Marven as a time traveller who investigates and encounters dinosaurs in the wild. The specials are known only by their individual titles (with the subtitle 'A Walking With Dinosaurs Special/Trilogy') on-screen; The umbrella title 'Chased by Dinosaurs' was used to market the series in the United States. The production company Impossible Pictures and producer Jasper James would produce