Ulysse Mérou was the main protagonist of the French novel La Planète des singes. He was a journalist and a friend of Professor Antelle. He accompanied Antelle and his colleague Arthur Levain on a mission to the giant red sun Betelgeuse. On the nearby planet of Soror, they encountered a naked woman by a pool of water they discovered on the planet.
The woman frighten by by the strange men interacted with them by playing a simple game in the water. Ulysse noticing its simplicity, the lack of expression and use of vocal chords in the girl decided to experiment. He smiled at her attempting a provoke a response, and she responded in fear, retracting from the water. Her manner became worse when she saw Hector, his presence caused her to leap and immediately strangle the chimp before fleeing back into the forest. Despite the disastrous first contact both Levain and Ulysse overuse Antelel in relocating to a more civilized location on the planet in favor of repairing relations with the girl. Ulysse secretly christens her Nova after becoming entranced by her natural beauty.
They meet Nova back at the pool of water, who is accompanied by her tribe. The three astronauts strip and take to the water, engaging with the inhabitants in the same simple game Nova had laid out before.Likewise Ulysse notices their lack of expressions, an other attempt to provoke a emotional response ends in disaster when the astronauts laughter causes the savage men and women to turn on them. Ulysse, along with his fellows were stripped of all articles and dragged back to Nova's colony.
After Ulysse was captured by the intelligent apes that dominated the planet, Ulysse was interned in the Institute for Advanced Biological Study. While held captive as a test subject in the study of man, Ulysse made many attempts to prove his intelligence by mimicking Zaius and displaying his ability to speak the simian language.
Later Zaius paired the Earthman with the Sororian woman in a study of sexual selectivity. When the Earthman refused to engage in relations with her, Zaius replaced her as the designated mate to Ulysses's neighbor. She was returned to him and spared the humiliation when Ulysses finally responded in the manner of a savage man.
With pride and defiance Ulysse passed each test the apes thought-up, but was still regarded as a highly intelligent animal. For a month Ulysse lived the life of a pampered animal, and was nearky content to remain in the Institute devoid of his freedom. However after rethinking his situation and his shameful behavior, it prompted Ulysse to communicate with the ape director Zira. Through the use of mathematical equations and drawings Ulysse was able to display himself as a rational being.
With the help of her fiance Cornélius, Ulysse was able to bring his case to the Grand Council and free himself from captivity. After he became a free man, he stayed with the institute, acting as a collaborator in the study of man. He attempted to teach the men at the Institute, but they proved to have very little motivation. He met greater success with his former cell mate Nova who sought to please him during her lessons ever since he was freed. However due to his human-self Ulysse kept their former intimacy at a distance. To his eyes she was an animal on this world despite her human form and only saw a physical relationship.
During his time on Soror, Ulysse delved in learning the true origins of the simian civilization and the primitive men. He traveled with Cornelius to a dig-site where a great ancient city was unearth. It contained common articles current in modern day simian society, however apparently it was home to a race of civilized men.
It is later revealed that during his intimacy with Nova, he impregnated her, lowering his standing in the eyes of the apes. Later he attended a ground-breaking experiment by a young chimpanzee scientist, who discovered a way to reawaken the memory of the human species. He was horrified to learn of the regression of the human race and the subsequent rise of the apes on Soror.
Ulysse was ultimately forced to escape back to Earth along with Nova and their newborn son Sirius from the alien ape planet. While he was reluctant to abandon Soror and its his fellow men to their fate, his two chimpanzee friends convinced it was in his best interest and family. Upon his return, he discovered that Earth had meantime been taken over by apes too, thus forcing his family to once again flee into space. His first-person journal (which formed the narrative of the book) was left floating idly through interstellar space in a cheap glass bottle, to be found by space-travellers Jinn and Phyllis.
- The character of Ulysse Mérou inspired 'George Taylor' (originally 'John Thomas'), the protagonist of the movie adaptation, Planet of the Apes. Taylor's fate remained largely unchanged, except that in the original book he was a journalist accompanying the mission, rather than its leader; and he ultimately escaped back to Earth from an alien ape planet and discovered that Earth had meantime been taken over by apes too, rather than discovering the alien planet was actually Earth.