In the last two posts on Jurassic Park, I detailed the multiple differences between the human characters of the film and their original novel counterparts. Now, I’ll deal with some not so human characters; the dinosaurs. It’s worth noting that the Park in the novel is far more finished, and the Dinosaurs appear more regularly on the tour, before things go bad.
The main bad guys of both the book and the film are the Velociraptors. However, we only see five in the film-the one killed in the opening sequence, the hatchling Raptor, and the three others who menace our heroes.
Much has been made about how the film velociraptors don’t resemble real ones at all-whereas the movie features massive, 6-foot tall Raptors, the actual Velociraptor-and it’s novel counterpart-were actually about four feet tall (But still very dangerous in the novel) and possessed a longer snout.
A 90’s era reconstruction of a Velociraptor, contemporary with the writing of the novel. It’s generally agreed that they had feathers, now.
The Tyrannosaurus is largely the same, with a few differences-there are two, the larger one which chases our heroes around, and a younger one that’s not quite as active. There are a few extra scenes involving the Rex, including a scene where it attacks Grant, Tim and Lex on a raft, and also near a waterfall. Both scenes were later adapted in the Jurassic Park film sequels, although Jurassic Park III substituted the Rex with a Spinosaurus.
In the film, the tour group comes across an ailing Triceratops, with Ellie attempting to find the cause of the creature’s sickness. While Triceratops do appear in the novel, the role of the sick Dinosaur is instead given to a Stegosaurus, who eventually do appear in the film’s sequel, The Lost World, as well as the last two films.
In the novel, Grant and the kids stumble upon an aviary containing flying reptiles, Cearadactyls. This sequence doesn’t appear in the film, but is semi-adapted in Jurassic Park III.
In The Lost World, Jurassic Park III, and Jurassic World,these reptiles are instead represented by the more popular Pterandon.
In the novel, the creature Procompsonathus makes many appearances. These small Dinosaurs injure a young girl on the mainland in the novel (a scene later used to open The Lost World)-prompting in part an investigation into the island’s security by Hammond’s investors (and also confusing Grant and Ellie as to how such a creature could still exist until they get to the park)also cause trouble in several villages, and eventually kill an injured Hammond.
The Compsonathus is introduced movie-wise in The Lost World, where it does many of the same things, although instead of Hammond, they eat Roland Tembo’s second-in-command, Dieter Stark.
The Brachiosaur in the film is pretty much the first major reveal of the Dinosaurs in the park. The majestic animal shocks the tour group, and many people in the audience watching the film. It (as well as a lot of the film’s other effects) still largely is impressive today, despite over twenty years of advances in special effects.
In the novel, the Dinosaur Grant and the crew first encounter is an Apatosaurus, sort of also known as Brontosaurus (It’s a long, long story). 
The Apatosaurus would sit out the films until Jurassic World, where it’s part of a memorable scene where Owen and Claire counsel the dying animal (injured by the Indominus Rex on it’s rampage) in it’s final moments.
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