 To create the dinosaurs , Spielberg at first thought of hiring Bob Gurr , who designed a giant mechanical King Kong for Universal Studios Hollywood 's King Kong Encounter . Upon considering that the life @-@ sized dinosaurs would be too expensive and not all convincing , Spielberg instead sought the best effects supervisors in Hollywood . Brought in were Stan Winston to create the animatronic dinosaurs , Phil Tippett to create go motion dinosaurs for long shots credited as Dinosaur Supervisor , Michael Lantieri to supervise the on @-@ set effects , and Dennis Muren of Industrial Light & Magic to do the digital compositing . Paleontologist Jack Horner supervised the designs , to help fulfill Spielberg 's desire to portray the dinosaurs as animals rather than monsters . This led to the entry of certain concepts about dinosaurs , such as the theory that dinosaurs evolved into birds and had very little in common with lizards . One of the first consequences was the removal of the raptors ' flicking tongues in Tippett 's early animatics , as Horner complained it was implausible . Winston 's department created fully detailed models of the dinosaurs before molding latex skins , which were fitted over complex robotics . Tippett created stop @-@ motion animatics of both the raptors in the kitchen and the Tyrannosaurus attacking the car . But despite go motion 's attempts at motion blurs , Spielberg still found the end results unsatisfactory in terms of working in a live @-@ action feature film . Muren declared to Spielberg that he thought the dinosaurs could be built through computer @-@ generated imagery , and the director asked him to prove it . ILM animators Mark <unk> and Steve Williams developed a computer @-@ generated walk cycle for the T. rex skeleton , and were approved to do more . When Spielberg and Tippett saw an animatic of the T. rex chasing a herd of Gallimimus , Spielberg said , " You 're out of a job , " to which Tippett replied , " Don 't you mean extinct ? " Spielberg later wrote both the animatic and his dialogue between him and Tippett into the script , as a conversation between Malcolm and Grant . Although no go motion was used , Tippett and his animators were still used by the production to supervise dinosaur movement . Tippett acted as a consultant regarding dinosaur anatomy , and his stop motion animators were re @-@ trained as computer animators . The animatics made by Tippett 's team were also used along with the storyboards as a reference for what would be shot during the action sequences . ILM 's artists were sent to private tours to the local animal park so they could study large animals — rhinos , elephants , alligators , and giraffes — up close , and also received mime classes for understanding movements . 
