I guess they are gearing up for the new Dawn of the Planet of the Apes movie because Hulu has begun to stream the entire 13 episodes of the 1975 animated series! Originally airing on September 6, 1975 until September 4, 1976 the series was produced by DePatie-Freleng Enterprises in association with 20th Century Fox. DePatie-Freleng Enterprises you might recognize for producing the Pink Panther shorts as well as the some of the Dr. Seuss TV specials that ran on ABC and CBS, they also produced the Time for Timer and The Bod Squad shorts.
Return to the Planet of the Apes, besides having one of the most frightening openings of an animated series that I can recall, also ties into the Planet of the Apes Movies and TV series (Which also had a scary opening). You’ll see General Urko, Zira, Cornelius, Dr. Zaius, Brent and Nova during the 13 episodes!