“Survival of the fittest” isn’t just the tagline for 2001’s Jurassic Park III — it’s the premise for Jurassic World Rebirth. “Of all species that have existed on Earth, 99.9% of them are now extinct,” paleontologist Dr. Henry Loomis (Jonathan Bailey) says on Ile Saint-Hubert, the site of a research and development complex for the original Jurassic Park. “Survival is a long shot.” The island, with its oxygen-rich tropical climate, is where two dozen species of dinosaurs have survived alone for almost two decades, even as others across the world died off in the five years since the events of 2022’s Jurassic World Dominion.
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Loomis studied as a postdoc under child-phobic paleontologist Dr. Alan Grant (Sam Neill) — who journeyed to Isla Nublar in 1993’s Jurassic Park and Isla Sorna in 2001’s Jurassic Park III, only to be drawn back into the Jurassic world in Dominion — and when we meet him in Rebirth, Loomis is advising pharmaceutical engineering company Parker-Genix on paleo-coronary health. Under the supervision of Martin Krebs (Rupert Friend), Parker-Genix is developing a new drug, Paleo-Dioxin, which Krebs says could forestall coronary disease by an average of 20 years and, eventually, make heart disease extinct.
Parker-Genix scientists require samples from living dinosaurs, so mercenary Zora Bennett (Scarlett Johansson) is contracted to lead a team to the island and extract DNA from three of the biggest animals across three categories: sea (Mosasaurus), land (Titanosaurus), and air (Quetzalcoatlus). While en route to the island aboard Duncan Kincaid’s (Mahershala Ali) boat, the covert op becomes a search and rescue mission when Bennett’s team intercepts a distress signal from a sailboat capsized by the Mosasaur in the Spinosaurus-swarmed waters surrounding the island.
The shipwrecked Delgados — dad Ruben (Manuel Garcia-Rulfo), teenage daughter Teresa (Luna Blaise), her boyfriend Xavier (David Iacono), and younger daughter Isabella (Audrina Miranda) — are brought to land, but then have to survive a perilous trek through a jungle teeming with dinosaurs and genetically-altered crossbred mutant dinos in order to reach a village complex as the mercenaries complete their mission.
It’s a concept reminiscent of an unused script for Jurassic Park III by screenwriter Craig Rosenberg (The Boys), in which a group of teenagers are marooned on Isla Sorna, a.k.a InGen’s Site B, that serves as the setting of the Joe Johnston-directed threequel.
“There were two other versions of this story that were written,” Johnston told About in an archived 2001 interview. “There were two other complete versions of Jurassic Park III that we wrote, and storyboarded, and scheduled, and then threw away. Five weeks before we started shooting this movie, we threw the script out and started over.”
When writing began in 1999, two years after Steven Spielberg’s 1997 Jurassic Park sequel The Lost World: Jurassic Park, Rosenberg “wrote a script in June of ’99 that was about five or six teenagers who get marooned on the island,” Johnston said, adding the script was “discouraging, even though it was not a badly written script.”
“It was actually good for what it was, but I don’t think anybody wanted to see that movie,” he continued. “And there was another one that was actually storyboarded and scheduled, and budgeted, and we scouted locations for it, and even started to build sets for some of it.”
The alternate version “was sort of a similar idea, although it didn’t involve a rescue,” he said, revealing it instead focused on Grant and his assistant Billy (Alessandro Nivola). “It involved a family with a kid, and Grant and Billy crash landing accidentally on the island.”
“It had, as a parallel story, a whole Costa Rican mainland thing where dinosaurs were getting onto the mainland and killing people and they didn’t know who, what, or why it was [happening],” Johnston said, revealing the culprits to be the winged Pteranodons.
Spielberg wanted to feature the flying carnivores in Jurassic Park and The Lost World, but it wasn’t until Jurassic Park III that the Pteranodons had a large role alongside the movie’s star dinosaur: the Spinosaurus. Also cut from III was the Kronosaurus, a marine reptile that had been planned for an underwater sequence. (The water-dwelling dinosaur was also cut from 2015’s Jurassic World and replaced by the Mosasaurus, which returns alongside the Spinos in Rebirth.)
In 2001, Johnston disclosed executive producer Spielberg’s original idea for the third Jurassic Park movie, telling Movieline magazine, “It was Steven’s idea to have [Dr. Alan Grant] discovered living on the island. He’d snuck in, after not being allowed in to research the dinosaurs, and was living in a tree like Robinson Crusoe. But I couldn’t imagine this guy wanting to get back on any island that had dinosaurs in it after the first movie.”
Ultimately, Jurassic Park III got Neill’s Alan Grant back on the island by having the Kirbys (William H. Macy and Téa Leoni) charter an airplane to fly them over Isla Sorna with the dinosaur expert as their well-paid guide. But when the plane landed on the island, Grant and Billy learned the Kirbys were looking for someone — their survivalist son, 12-year-old Eric (Trevor Morgan), who disappeared while parasailing off the coast eight weeks earlier — and that their trip to Isla Sorna was a rescue mission.

While Peter Buchman, Alexander Payne, and Jim Taylor are credited for the screenplay, it was David Koepp — the screenwriter of Jurassic Park and The Lost World: Jurassic Park who returned to the dinosaur franchise for Jurassic World Rebirth — who had the idea to make Jurassic Park III a rescue mission about a stranded survivor on the island. Koepp’s idea survived even as the script evolved.
“It was a completely different story, but Steven was involved in sort of helping to conceive all the different stories,” Johnston told About. “Then when David Koepp came up with the last idea for the rescue mission, Steven embraced it as completely as everyone else did, and we all said almost at the same time, ‘Yeah, we have to start over. We have to throw out what we’ve got because this is a better idea.’”
Jurassic World Rebirth is now playing only in theaters.