A helicopter and the Costa Rican National Guard are on the way. Grant, Sattler, Muldoon, and a reluctant Gennaro go to find the raptor nest to determine if any animals have gotten off the island. On the way, Grant explains how the dinosaurs were able to reproduce: certain species of frogs can spontaneously change their gender when they are in an environment in which all of the animals are the same sex. The dinosaurs with the frog DNA, therefore, must have retained that trait. Once they are at the raptor nest, Gennaro refuses to go down the nest hole, but Grant says he must own up to his responsibility.
Hammond takes a walk and muses that, even if Gennaro shuts down his island, he still has frozen embryos safely stored in California. Tim and Lex fool around in the control room, playing a recorded tyrannosaur roar over the park's loudspeakers. Hammond hears the roar and, thinking he is about to be attacked, trips and falls down a ravine.
Grant and Sattler go down the hole of the raptor nest and Muldoon forces Gennaro to follow. The large manmade cavern is teeming with raptors of all ages. The three observe the animals as they seem to line up and suddenly all run down a concrete tunnel.
Hammond is attacked and overwhelmed by a group of compys.
Grant, Sattler, and Gennaro follow the raptors, emerging from the tunnel on the beach. The raptors again line up in a northeast-southwest formation and Grant assumes that they want to migrate.
Helicopters scare off the raptors while soldiers take Grant, Sattler, and Gennaro into a chopper where Muldoon and the kids are already on board. Muldoon informs them that Hammond and Malcolm are dead. The soldiers want to know who is in charge, but no one is.
The government retains everyone at a hotel for questioning. Guitierrez comes to visit and informs Grant that some animals had been eating local crops in a peculiar manner. They moved in a straight line from the coast into the mountain jungle, eating agama beans and soy—foods rich in lysine. The animals disappeared into the jungle, and now no one knows where they are.
As the novel closes, we see that many characters meet fates that can been seen as appropriate or just deserts. Nedry, who endangers the entire island through his greed, is killed by dilophosaurs. Muldoon even notes the appropriateness of his demise after he finds Nedry's carcass: "Maybe there's justice in the world after all." Regis cowardly abandons the children, and in so doing seals his own fate. Although Hammond claims to have created the park for the children of the world, he modifies this statement and admits that only the world's richest kids would ever get to see his dinosaurs. Ultimately, all Hammond wants is to make a lot of money. Even after witnessing all the death and destruction his scheme causes on Isla Nublar, Hammond still intends to make another park with frozen embryos that he has in storage. The fact that his death comes about due to his own grandchildren, albeit accidentally and indirectly, adds irony to his fate.
Similarly, Arnold, so certain that he has everything under control, allows his confidence to lead to carelessness. It is fitting that he dies while trying to cover for his mistake, that he left the auxiliary power on. Dr. Wu never intends any harm, but conducts his manipulation of biology and genetics with such ignorance for the animals he is creating that it is no wonder he pays a price for messing with nature. Likewise, Gennaro, though always skeptical that Jurassic Park is not safe enough for visitors, still schemes about making a fortune from Hammond's idea. Though Gennaro manages to survive, Grant forces him to help scope out the raptor nest before he leaves the island— a duty that Gennaro initially refuses to accept. Grant is adamant, however, that take responsibility for his part in creating this park. In a sense, then, though Gennaro survives, he nonetheless pays his dues.
Meanwhile, the main protagonists and seemingly responsible characters—Grant, Sattler, Tim, and Lex—all survive virtually unscratched. Muldoon, who always has had reservations about the park's safety and Hammond's methods, and who tirelessly fights to keep the dinosaurs in check, also makes it out alive. Harding, the unassuming vet whom we never see committing any significant wrong, manages to survive as well.
The only confusing character is Malcolm, who has all along told Hammond not to build the park because it is a bad idea. It may seem somewhat odd, then, that he dies. Perhaps Malcolm's certainty that chaos theory and its fatal implications for the island will prove true actually wills his own death in a sense. Alternatively, it may be that Crichton is merely rewarding Malcolm's smug, swaggering arrogance with particularly harsh retribution.