A large number of clips featuring computer generated dinosaurs have been taken from other dinosaur documentaries, such as When Dinosaurs Roamed America (2001), Dinosaur Planet (2003) and Clash of the Dinosaurs (2009), and a lot of times, these stock-footage clips clash with what the narration describes. For instance, clips of abelisaurs or carnosaurs are played when tyrannosaurs are being discussed, and one clip shows a three-horned Triceratops as the narrator describes the much more primitive and hornless Protoceratops.