Jurassic Park's dinosaur sound effects were animal sex noise

In the 1993 movie 'Jurassic Park', the sound of Velociraptors barking at each other to communicate, is actually the sound of tortoises having sex, as revealed by sound designer Gary Rydstrom. Further, the sound of Gallimimus was based on the sound of a female horse, who had a male horse coming at her during her reproductive cycle.