Dr. Zaius is the senior orangutan official in Ape city. He served as both Minister of Science and Chief Defender of the faith admitting no contradition between the two roles. He was also caretaker of many secret ideas, kept from the simian civilization at large.
Played by many actors, Zaius is often referred to as a villain, since his goal is to exterminate the species. "It's a question of simian survival."
However, in Pierre Boulle's original novel Planet of the Apes, "Mi Zaius," is devoid of any dialogue.