roar and, startled, falls down a hill, where he is eaten by a pack of Procompsognathus. Grant deduces that using frog DNA to fill gaps in the dinosaurs' genetic code enabled a measure of dichogamy, in which some of the female animals changed into males in response to the same-sex environment. The computer tally failed to include newborn animals, having been programmed to stop counting once the assumed correct total number of animals had been found. The survivors are rescued by the Costa Rican Air Force, which declare the island hazardous and unsafe, and proceed to raze the island with napalm. Survivors of the incident are indefinitely detained by the United States and Costa Rican governments at a hotel. Weeks later, Grant is visited by Dr. Martin Guitierrez, an American doctor who lives in Costa Rica. Guitierrez informs Grant that an unknown pack of animals has been migrating through the Costa Rican jungle, eating lysine-rich crops and chickens, indicating the dinosaurs may still exist in the wild. Development The novel began as a screenplay Crichton wrote in 1983, about a graduate student who recreates a pterosaur. Eventually, given his reasoning that genetic research is expensive and "there is no pressing need to create a dinosaur", Crichton concluded that it would emerge from a "desire to entertain", leading to a wildlife park of extinct animals. Originally, the story was told from the point of view of a child, but Crichton changed it as everyone who read the draft felt it would be better if told by an adult. Prehistoric animals featured The following specified prehistoric animals are featured in the novel: Apatosaurus – Referred to as Brontosaurus by some characters. Replaced by Camarasaurus in some editions. Population 17. Cearadactylus – Referred to as Pterodactylus by some characters. Population 6. Dilophosaurus – Population 7. Dryosaurus – Usually referred to as Hypsilophodont. Population 34. Euoplocephalus – Population 16. Hadrosaurus – Population 11. Maiasaura – Population 22. Microceratus – Referred to as invalid junior synonym Microceratops. Replaced by Callovosaurus in some editions. Population 22. Nanosaurus – Referred to as invalid junior synonym Othnielia. Population 23. Procompsognathus – Population 65. Stegosaurus – Population 4. Styracosaurus – Population 18. Triceratops – Population 8. Tyrannosaurus – Population 2. Velociraptor – Population 37. Animals in which their origin, genus and population are unspecified are the following: Giant dragonflies Unhatched herbivorous Coelurosauria - Referred to as informal generic name