Dr. Zira is a chimpanzee psychologist and veterinarian, who specializes in the study of humans, in the novel and subsequent movie series Planet of the Apes. Zira was played in the first three Apes movies by actress Kim Hunter. Unique among the Apes characters, Zira has blue eyes.
Zira is the fiancée (later wife) of Cornelius, and both are ultimately responsible to the Minister of Science, Dr. Zaius. Zira's character and role are essentially the same in both the novel and the movies, though some story details differ. Her work in each involves both working with humans under laboratory conditions (e.g. learning and behavioural experiments), and working on them physically (lobotomy and other brain surgeries, vivisection, physical endurance and tolerance experiments, and subsequent autopsies). Zira is an outspoken liberal by nature, deploring war and militancy (and despising the gorillas, who seem to make both a way of life), and eager to seek and develop intelligence anywhere it can be found. Zira literally stands for her principles - or refuses to stand, as the case may be.
In the original novel, Zira discovers that her charge Ulysse Mérou (caged in the laboratory where she works) isn't a native-born, mute human of her planet, but a space traveller capable of speech, and she secretly teaches him the language of the apes, in hopes of eventually making a public demonstration, with Mérou's consent. Cornelius also becomes involved, helping prepare Mérou to meet ape society, and vice versa.
In the first movie, Zira meets American astronaut George Taylor, who was shot in the throat when he was captured by gorillas, and cannot speak, as the native humans of her world cannot. She tends to his throat wound, discovers Taylor has intelligence beyond any human she's seen, and pairs him with Nova, also intelligent, hoping the two will breed. When Taylor steals Zira's notepad and writes his own name on it, Zira abruptly drops the nickname "Bright Eyes" she'd given him, and takes Taylor to meet Cornelius. Both disbelieve Taylor's story that he's from another planet, but suppose that he might be a missing link, to explain the similarities between ape and human behaviour and anatomy... and the strange artifacts Cornelius found at an archaeological dig the year before. She seems to be fond of the humans that she works with and gives them nicknames, such as an old one she named "Old Timer".
In both novel and movie, Zira ultimately helps Mérou/Taylor and Nova to escape the world of the apes, coming to appreciate each as thinking creatures like herself, as well as having a plain fondness for them. In the movie, she and Taylor kiss goodbye – even though, as she tells him, "You're so damned ugly."