In "Jurassic Park," you can't tell the dinosaurs without a scor card. Here, courtesy of Johns Hopkins paleobiologist David P. Weishampel, is a breakdown of the beasts in the film:
* Brachiosaurus weighed 80 tons and was about 75 feet long. It was a vegetarian and possibly social. It lived in the western United States and in Tanzania during the Jurassic Period,
roughly 150 million years ago. "Jurassic Park" pictures it as the most gentle, innocent and majestic of the dinosaurs.
* Parasaurolophus is more famous as the duck-billed dinosaur. It weighed 3 tons and was 30 feet long. It was social and lived in western North America, where it grazed much like an elephant or rhino. A more recent dinosaur, it dated from the Cretaceous Period, roughly 70 million years ago.
* Tyrannosaurus rex is probably one of the most famous and ferocious of all the dinosaurs, but there is some debate as to whether it deserves its reputation. With those small forearms, some paleobiologists question whether it could rip its prey apart; possibly it was a big scavenger. It was 40 feet long, weighed 7 tons, dated from the Cretaceous, was definitely a meat-eater and lived in western Canada and the United States. It was not particularly social.
* Dilophosaurus was a smaller meat-eater, about 20 feet long, weighing about 500 pounds. It was possibly social and had a peculiar headdress of bone, which the movie speculatively chooses to interpret as a red hood that opens when it is agitated to give it a particularly demonic appearance. The movie also portrays it as spitting a toxic saliva as part of its hunting technique, but that too is speculative. Remains have been found in New Mexico, and it dates from the Jurassic Period.
* Triceratops is another more famous dinosaur. This tri-horned creature, which looked like an armored vehicle, was a plant-eater from the Cretaceous. It was 30 feet long, weighed 7 tons and was found in western North America.
* Velociraptor, the movie's most cunning and treacherous animal, was somewhat oversized by director Steven Spielberg. The creature was man-sized, 6 feet long, weighed about 200 pounds, was a meat-eater and was social (it hunted in packs). It populated Mongolia and China during the Cretaceous Period. Dr. Weishampel feels that a scene showing its legs in close-up as it stalks prey were the most inaccurate thing in the film.
"We know quite a bit about velociraptor's gait. It was a very narrow gait, almost man-dimensioned. A frequently repeated close-up of its feet stomping down the floor places them much too far apart, suggesting that it's much bigger than it really was."