Random Trivia For This Title:
- According to the book Planet of the Apes Revisited, Don Pedro Colley's character is named "Ono Goro" in the screenplay. Colley was bemused to discover that he was credited as "Negro" in the end titles.
- Charlton Heston was reluctant to reprise the role of George Taylor for this movie. He eventually agreed on condition that his scenes had to be shot within a two week period. He also insisted that Taylor had to be killed. He agreed to a compromise in which he'd disappear in the beginning of the film and reappear to die at the end.
- Charlton Heston claims in the documentary Behind the Planet of the Apes that he personally suggested the ending, saying, "Why don't I just set off this bomb and destroy the world. That's the end of the sequels."
- Originally, there was going to be a scene featuring a half-human/half-ape child. However, the producers were afraid that not only would the scene be too confusing, but that they would also lose their "G" rating.
- As of January 2008 the total domestic gross for Beneath the Planet of the Apes is estimated at $18,999,718. Because of its modest budget of just $3 million, percentage-wise "Beneath," despite wide agreement that it's one of the worst of the series, has remained the most profitable of all the "Apes" films, including the 2001 remake.
- This was the first appearance of Natalie Trundy in the "Apes" series. She is the only person to play both a human and an ape in the series.
- James Franciscus was cast as Brent due to his resemblance to Charlton Heston.
- An alternate ending was written where Taylor, Brent and Nova escape the underground prior to the bomb's detonation (it wasn't written as a doomsday bomb yet). They return to Ape City and, along with Zira and Cornelius, release the humans from the cages and a new order is begun. The script ends hundreds of years later with the Lawgiver teaching a group of ape and human children sitting in harmony together. The "Lawgiver Scene" was resurrected as the framing structure for Battle for the Planet of the Apes. The final shot of the script shows a mutated gorilla emerging from the underground and fatally shooting a flying dove.
- Burt Reynolds was considered the lead role of John Brent.
- Orson Welles was offered the role of General Ursus which he turned down.
- The only film in the original series of five that does not star Roddy McDowall. Despite this, McDowall is often pictured on video and DVD packaging for this film. Roddy McDowall was unable to appear in this film because he was committed to another project. He can, however, be spotted briefly in the opening prologue, even though another actor plays the role later in the film.