Bluth had to learn most of his information about specific dinosaur species before work began, stating "I had to do lots and lots of research because I never was a fanatic about dinosaurs as a kid. But in many ways it became a fictional fantasy because it's about these young children who are taught to hate each other; anyone who is different from him. When they are separated from their parents, these five little children have to learn to get along with each other for survival. So there is a bit of a moral in it, too." The films creators decided to have a "Tyrannosaurus" as the main villain.