As the emotional sounds that chimps make do not in any way resemble those of humans, it was decided to create their vocalizations using actors. Every chimp sound in the picture, other than one very brief outburst, is ADR. The role of Goliath, the giant ape, was voiced by the African-American actor 'Arthur Burghart', who played Dr. Jack Scott on "One Life at a Time" and the smallest female chimp, Daisy, was voiced by 'Annie Lockhart' of "Battleship Gallactica" fame. Norman B. Schwartz was the vocal effects director.