Here's a breakdown:
* Real animal sounds: The filmmakers recorded sounds from a variety of animals, such as elephants, whales, dolphins, alligators, and birds. These were then manipulated and layered to create the roars, hisses, and other noises of the dinosaurs.
* Modified animal sounds: They also used recordings of existing animal sounds, like those of walruses, tigers, and even a baby elephant, and manipulated them with pitch-shifting and other techniques to make them sound more "dinosaur-like."
* Synthesized sounds: For some of the more unique and alien sounds, the team used synthesizers and other electronic instruments to create sounds that were entirely original.
Here are some specific examples:
* T-Rex: The iconic roar of the T-Rex was created by layering the sound of an elephant, a walrus, and a tiger, and then manipulating their frequencies to create a deep, powerful roar.
* Brachiosaurus: The Brachiosaurus's deep, resonant call was created by using a combination of a synthesized sound and a slowed-down version of a whale call.
* Velociraptors: The Velociraptors' distinctive screech was created by manipulating the sound of a bird's call and adding some synthesized elements.
The filmmakers carefully chose and combined these sounds to create realistic and terrifying dinosaur noises that have become iconic in the film industry.