 Brachiosaurus is the first dinosaur seen by the park 's visitors . It is inaccurately depicted as chewing its food , and standing up on its hind legs to browse among the high tree branches . According to artist Andy <unk> , the chewing was done to make the animal seem docile , in a way it resembled a cow chewing its cud . The dinosaur 's head and upper neck was the largest puppet without hydraulics built for the film . Despite scientific evidence of their having limited vocal capabilities , sound designer Gary Rydstrom decided to represent them with whale songs and donkey calls to give them a melodic sense of wonder . Penguins were also recorded to be used in the noises of the dinosaurs . 
