Carl Gottlieb is best known as a screenwriter for films such as Jaws or Which Way Is Up? and it was the success of his screenplay for The Jerk that allowed him the opportunity to direct and write the 1981 feature Caveman.
Aside from all dialogue being spoken in a form of a caveman language two other factors make this film notable: the stunt casting of ex-Beatle Ringo Starr and the special effects dinosaurs. Also filling out the cast are: former football player John Matuszak, Barbara Bach (who would begin an on-set romance with Ringo Starr which continues to this day), Dennis Quaid, and Shelley Long in her first major role in a motion picture.
Special effects artist Jim Danforth began work creating the dinosaurs as well as making other contributions but according to IMDb trivia after two thirds of the film was finished, Danforth had to leave the production because "the Directors Guild of America allegedly disallowed his already contracted co-director credit alongside director Carl Gottlieb. As such, Danforth is not credited as a director on this picture, only for special effects and second unit director."