The portrayal of several dinosaurs differs from that of the previous two films (Jurassic Park and The lost world: Jurassic park). Due to new discoveries and theories in the field of paleontology suggesting that Velociraptors were feathered, the male Velociraptors in the film have quill-like structures on the head and neck.
Originally, the film included Jeff Goldblum and his character, Ian Malcolm. But a few days into filming, Goldblum injured his leg and decided to drop out, stating that his character wasn't that important to the script.
Dr. Grant's brown truck with the Museum of the Rockies and Montanta State University logos on it is actually based on the vehicle that belongs to Dr. Jack Horner, paleontologist consultant on the Jurassic Park films as well as the man that the character of Grant is based on. It was a difficult and time consuming process to find an exact match of Dr. Horner's truck to be used in the movie.
The establishing wide shot of the dig site was actual footage filmed in early summer 2001 of Jack Horner's excavation, which contained several large Tyrannosaurs and some Hadrosaurs.
The Spinosaurus was the largest animatronic ever built. It weighed 12 tons and was operated by hydraulics. This allowed it to operate while completely submerged in water.
The effects crew used 250 gallons of oatmeal to simulate Spinosaur droppings.
When Ellie is talking to Grant she mentions getting a quote from Jack Horner for her book. Jack Horner is a paleontologist who was Michael Crichton's inspiration for the character of Alan Grant; he was also a consultant on all of the three "Jurassic Park" films.
When the paleontologists enter the bar for dinner with the Kirby's, you can see a Jurassic Park (1993) pinball machine in the background.
After the Spinosaurus' attack on the airplane, Grant asks Billy how he would classify the animal. Billy's first inclination is to say the dinosaur is a Suchomimus or Baryonyx, due to the large snout. This is a joke meant for many fans of the film who, when the new movie's logo was first revealed, said the exact same thing Billy did. Many long pages on the message boards of fan pages and the official page were dedicated to this debate.
A few of the action sequences are borrowed from left over ideas from the first two Jurassic Park films, some of which were in the original scripts and made it as far as being storyboarded before they were scrapped due to time and budget constraints. These scenes include the pteranodon and river boat sequences.
Sam Neill, as part of his contract, requested that the Australasian premiere of the film took place in his hometown of Dunedin, New Zealand.
In the original shooting script, the character Udesky (Michael Jeter) was called Ordesky.
Original scripts and storyboards had a Baryonyx as the main dinosaur instead of the Spinosaurus. Baryonyx is a close relative of the Spinosaurus and they looked basically the same. Baryonyx was a little smaller, and did not have the fin like the Spinosaurus did. Director Joe Johnston wanted a main dinosaur that would not be confused with the T-Rex. Though the Baryonyx would have been vastly different, the Spinosaurus had a bizarre look no carnivore had.
Shooting for the film began before the final script was completed.
The Einhorn 20mm, the large weapon used by the mercenaries, was actually a Barrett M82A2 Bullpup sniper rifle, developed for the US military, but never adopted.
The 25 September 2000 draft of the screenplay credits revisions to John August. He is not credited in the final film.
Stellan Skarsgård, Steve Buscemi, and Tony Shalhoub were considered for the role of Cooper.
Near the end of the movie, when the Spinosaurus attacks Amanda Kirby (Téa Leoni) in the water and tries to grab her, the actress admits that she was injured by accident during those scenes when its claws would scratch her. When Leoni returned home from work one night and her husband David Duchovny saw the various slashes on her back she received during filming, he asked "At what point in this movie do they whip you?"
According to an interview with William H. Macy, the actor said the film's animatronic Spinosaurus had a 1,000-horsepower motor and that creature could turn its head at twice the force of gravity, with the tip of its nose moving at a speed of more than 100 miles per hour.
The computer-controlled "rapid prototyper" portrayed in the film is real technology, able to mechanically sculpt parts and objects in three dimensions using computerized drawings and scanned information. The machine in the film uses Laminated Object Manufacturing (LOM). Using one thin layer of bond paper and resin at a time, it carves away the unwanted material as each layer is added, until all the cross-sections have been built up into a solid replica of the original. The carving action of each layer creates a great deal of shavings and dust during the process, which you can see when Billy lifts the lid up to remove the finished model.
Michael Crichton worked with the screenwriters several days to brainstorm about a story, but left after some days when he could not come up with a satisfactory idea.