Originally Brontosaurus excelsus, this “Deceptive Lizard” was discovered & described in 1879 in Colorado by Othniel Charles Marsh. It was named such because Marsh thought its lower tail bones to be very similar to a mosasaur, and was thus nearly decieved. Apatosaurus lived during the Late Jurassic Period about 154 to 150 million years ago. It was 21 meters (about 70ft.) in length, 4.5 meters (15ft.) in height at the hips, & 40 tons in weight. Studies suggest that Apatosaurus had either a respiratory system unlike anything known today, or an avian respiratory system, as a Mammalian or Reptilian respiratory system would either not provide enough oxygen, or exceed the available space in the chest cavity. Footprints have shown that the juveniles were able to move on two legs.
Apatosaurus was first seen in the distance when the visitors arrived to Jurassic Park in 1989. They were described as moving quickly and gracefully and making a “low trumpeting sound, rather like an elephant.” They were seen again on the tour. Apatosaurus did not have any amphibian DNA fragments and was therefore never observed breeding with an expected population of 17, an actual population of 17 and an equilibrium population of 12. The Apatosaurs were last logged as version 3.1. In some editions of the first novel, Camarasaurus is added as one of Nublar’s inhabitants and it is classified as an Apatosaurus.
In the 1995 expeditions to Isla Sorna, they are first seen during the drive through Isla Sorna, their necks and heads visible to Malcolm, Thorne, and Eddie, much as when seen by Malcolm in 1989. They are seen later on drinking in the river, using their tails to form a defensive barrier so the juveniles can get a drink. Levine, Kelly, Arby and Thorne talk about the Apatosaurs, observing that they don’t raise their necks very high for very long. They conclude that the long necks evolved as a counterbalance to the long defensive tail. Malcolm also observes that in the Apatosaur herd, none of the dinosaurs are full sized adults. Next, Levine observes from the High Hide that the Apatosaurs are drinking with the Parasaurolophus. Not only, as Thorne points out, does this mean that they have a high metabolism requiring cooling, but a symbiosis with the Parasaurolophus. The Parasaurs act as the “eyes” of the group, spotting predators and alerting the Apatosaurs, who then protect the Parasaurs from the predators. The raptor nest is found situated next to the remains of multiple Apatosaurs, and their skeletons are observed by Levine and Thorne.