Continuity mistake: At the very beginning, when you see the English family on the beach, the little girl wanders off and you then see a shot of her on her own. However, she must have walked a pretty long way because the beach she is on is definitely not the beach that her parents were on; the rocks in the ocean are gone and the waves are smaller. (00:02:00)
Continuity mistake: When the English family arrives at the island, the sky is a bit gray. When the little girl wanders off, it is suddenly a sunny, beautiful day. (00:02:05)
Continuity mistake: When the girl holds the sandwich, the napkin around it changes size and position between shots. (00:02:20)
Continuity mistake: When the movie starts and the little girl is surrounded by mini dinosaurs, her father lowers his Financial Times newspaper twice. First in the closeup he lowers it to his lap, and then at the start of the next wideshot the newspaper is back up in front of his face when he lowers it again before it drops onto the sand. (00:02:40)
Continuity mistake: When the girl meets the mini dinosaur she is standing on the sand, parallel to the edge of the grass. A frame later she's half a meter away, perpendicular to the grass. (00:02:50)
Visible crew/equipment: When Ian is talking to John in the bedroom you can see a mirror. After John tells him about the project, the camera moves to the bed and there is a reflection of blue jeans, probably the cameraman's. (00:11:40)
Continuity mistake: When Ian starts to walk out of Dr. Hammond's office, we see an empty hallway. A shot or two later, there is a butler standing to the left of a lamp in the middle of the hallway. Then another shot or two later, the butler is standing to the left of the hallway where we can't see him. (00:13:50)
Continuity mistake: When the crew are looking for Sarah, Eddie is holding the tracker and Ian is holding the rifle. In the next wide shot where they watch the Stegosaurus cross the river Eddie is now holding the rifle and Ian the tracker and the bag. The scene cuts again to the close up and Eddie is again holding the tracker. (00:22:00)
Continuity mistake: When Sarah walks through the water when she sees Malcolm for the first time on the island her pants are soaked up to mid thigh, in the next scene she is running through the water again and her pants are only soaked up to her knees. (00:24:15)
Continuity mistake: Towards the beginning where the girl goes to photograph the Stegosaurus, the scene cuts back to her boyfriend and the guy with the video camera. In two cuts to their scene while the girl is photographing and interacting with Stegosaurus, the guy with the video camera opens the flip out LCD on the video camera and starts shooting the action. (00:24:50)
Revealing mistake: In the beginning of the movie, when the rescue group arrived on Isla Sorna, the actress grabs the Nikon F5 of the photographer and makes her way to the nest of the Stegosaurus. After several shots of the small Stegosaurus there is no more film left in the cassette, so the camera begins to rewind it automatically. The thing is, you never see the rewind knob moving although you hear the camera's motor rewinding (The Nikon F5 has a manual rewind knob to be able to rewind the film when the batteries are dead). There was obviously no film at all in the camera. (00:26:00)
Revealing mistake: When the stegosaurus begin to move around a lot, you can see the one that is charging at her steps in the creek water, but there is no splash or any ripples. (00:26:20)
Continuity mistake: When Sarah, Malcom and his daughter argue in the trailer for the first time you can see out of the back window. It shows they are right in front of a thicket of trees a few feet behind the trailer. When they step outside a minute later to see the InGen choppers arrive you see that the trailer is pulled up on the cliff tops already. The only view you should have seen out of that window was open sky as the window points out to sea. (00:32:10)
Character mistake: When they're on the island and the INGen helicopters are flying in, Jeff Goldblum takes the binoculars and looks through the wrong end. (00:32:30)
Continuity mistake: When the second INGEN team is rolling through the open field and you first see Rolland talking to Peter about not setting up camp on the game trail, if you look carefully in the shot looking at Peter they are actually on a paved road instead of open field. Split second mistake. (00:32:55)
Continuity mistake: When Rowland and the other man spot the baby T-rex, it is eating its meal. Then it looks up at them. Then it cuts to another shot where Rowland and the other man are talking. If you look in the background you can see the baby with his head down eating again. Then it cuts back to where the baby is. It is looking up at them again. (00:39:30)
Visible crew/equipment: When Sarah and Nick return to the trailer with the baby T-rex, there is a shot of Nick carrying the rex towards the operating table. Look between the baby rex's legs - there are a series of wires leading from a opening in the animatronic dinosaur's belly to a bulky device (presumably a battery pack) in the actor's pocket. Once you know where to look for the wires, you will notice them in many other shots in the film when various actors are holding the baby rex. (00:46:40)
Continuity mistake: In the scene where Sarah is helping the baby T-rex in the trailer and Ian is trying to dial up their ship on the radio, look at the papers Ian is holding. In one shot the back page is white, but in the very next shot, it has a red cover on the back. (00:49:20)
Continuity mistake: The night when the T-Rexes attack it is pouring and there is mud all over, but the next morning the grass is dry and not even in the forest is there any mud or rain puddles. (00:51:25 - 01:09:00)
Visible crew/equipment: When Sarah is returning the baby T-rex to the parent dinos, just as she is about to release the baby so it can "walk" back to its parents, look at the bottom of the screen. You can see someone's head pop up for a second, presumably a crew member taking the animatronic baby from Sarah. (00:55:55)
Answer: Just after she makes the statement, Ian sees the T-Rex outside of the van window and realises that it is going to attack them regardless of the fact that they've returned the baby Rex.