Factual error: In the early scene where Dennis Nedry meets a man to plan the embryo theft, the subtitle says that they are in San Jose, Costa Rica. However, the sleepy coastal town in the movie bears no resemblance to the real San Jose (a cosmopolitan capital of almost 1 million people, situated 50 miles from either coast). (00:13:10 - 00:14:45)
Factual error: When the doctor is showing off the piece of amber that they have gotten the DNA from, there is a problem. The mosquito in the amber is a male, as one can tell by the antennae. Because it is only the female mosquito that feeds on blood, the male should only have nectar in its stomach. To make it worse, in that species of mosquito, Toxirhynchites, both the males AND females are flower feeders, and would therefore have no blood, or dinosaur DNA in their stomachs. (00:25:00)
Factual error: The way the car "slides" down the tree as Grant and Tim are climbing down is very unrealistic. Rather than hugging the trunk like it does, the branches (some of which are thick enough) would deflect it away from the trunk. (01:13:30 - 01:15:00)
Factual error: In this film, Dilophosaurus is characterized as "one of the earliest carnivores." This is factually off by about 100 million years. The earliest large land carnivore was Dimetrodon (a reptile, not a dinosaur), from about 100 million years before Dilophosaurus. Before that, there were many marine and amphibious carnivores, dating back 300 million years easily.Charles Austin Miller
Factual error: At the beginning of the film we are shown an amber mine in the Dominican Republic. This amber is only 45 million years old, Hammond would never bother buying the amber from there as dinosaurs disappeared from the fossil record 65 million years ago.