Ross Geller’s pet monkey on Friends was named Marcel.
Ross adopts Marcel during the first season, explaining that the young capuchin monkey is legal to keep at that point in the story. Marcel quickly becomes part of the group’s comic situations, including scenes involving Ross’s attempts to care for him and the friends’ reactions to having a wild animal in the apartment.
The storyline eventually moves Marcel away from Ross. After being given to a zoo, Marcel is discovered to have become a movie and television performer. Ross later encounters him again during a visit connected with Marcel’s acting career.
Marcel is not Ross’s only unusual animal-related storyline. Ross also becomes involved with a pet-related dispute involving a cat that Phoebe believes contains her mother’s spirit. That separate plot can cause confusion, but Marcel is specifically the monkey Ross keeps in the first season.