|Continuity||La Planète des Singes|
|First Appearance||La Planète des Singes|
|Last Appearance||La Planète des Singes|
Mi Zaïus was a leading orangutan scientist on the ape-dominated planet of Soror, the title "Mi" denoting a rank of honour. The head of the Research Institute, he was informed by Zira that she had discovered a human who was capable of thought, and even of speech. Zaïus, who did not believe the fact that man could have a soul or a spirit, dismissed her claims as nonsense.
To prove his point, Zaius subjected Ulysse's to various tests and exercises and to much of his embarrassment failed to disprove the man's intelligence. It was he who assigned Ulysse to be paired with Nova to become mates.
He decreed that Ulysse's talents were due to highly developed animal instinct, and an asserted that he was a tame man, probably due to former period of captivity.
At a biological conference he intended to present his thesis on the remarkable trained mam, but was discredited when Ulysse Mérou made a convincing address to the ape masses.
Zaius was latter dismissed from his post as head of the Institute, being replaced by Cornelius. After shocking revelations from a ancient city and a chimpanzee's experiments concerning man, Zaius had been scheming with the orangutans against Cornelius and the Earth man.
When Sirius was born the Grand Council planned to place the boy under Zaius's charge to ensure that a new race of intelligent men did not become a reality.