Continuity mistake: Just after Alan gets Lex out the pushed over truck, the T-Rex walks up to them and it is standing about an inch away from them, but in the next shot, there is no sign of it, then reappears in the next shot. (01:08:25)
Trivia: An explanation of why the triceratops was sick is in the Michael Crichton novel and the original screenplay, and a deleted scene - the triceratops swallowed rocks to grind its food as it didn't have teeth that could manage this. Once the rocks were worn down in its stomach it vomited them back up, along with the poisonous lilac berries that it had unintentionally swallowed at the same time as the new rocks. This is why there are no berries or rocks in its mound of poop. Laura Dern briefly picks up some rocks and berries, clearly forming the connection, but the rest of the scene was cut.
Trivia: The T-Rex was named Roberta by the dinosaur supervisor Phil Tippett in the original storyboards for the film, and was a nickname for the animatronic amongst the crew. Fans more often call her Rexy.
Continuity mistake: When Nedry meets Dogson he cries "We've got Dogson here!" with the green napkin bundled inside his fist. From the opposite angle a big chunk is standing out.
Continuity mistake: When Hammond meets Grant and Sattler in the trailer he dries the glass with a white tea towel in his hands. A shot later it's pink. (00:11:32)
Continuity mistake: After Hammond says "Welcome to Jurassic Park" Alan is sitting on the floor with Ellie comforting him. A shot later she's gone, only to reappear 5 metres away in the next shot.
Continuity mistake: When the movie begins a worker on the top part of the crate falls to the ground, face down. A split second later he's facing upwards.
Continuity mistake: When Grant is feeding a dinosaur in the morning he is either holding the food with one hand or two depending on the shot.
Continuity mistake: When the Dilophosaur spits on Nedry the second time, it is only on his forehead and eyes. In the next shot, a second later, it is all over his face and cheeks. It was too soon for the rain to have washed it down that far.
Answer: They are not paleontologists, just people interested in dinosaurs. It is common for museums and other scientific organizations to offer the general public an opportunity to participate in a real paleontology dig. For a fee, they become an exhibition team member for a period of time, learn about dinosaurs, help excavate fossils, and so on. This is likely how Dr. Grant (or his institution) supplements his research funding.
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