In 1922, in Kindia (French Guinea), the bacteriologist Albert Calmette launched an overseas Pasteur Institute (commonly known as “Pastoria”), which used apes as its central research model. When, in 1949, the colonel physician Gustave Lefrou took charge of Pastoria, he faced the task of dealing with apes, something he had never experienced during his career as a clinical physician in the tropics. Lefrou was the author of Le Noir d’Afrique. Anthropo-biologie et raciologie (1943), where he challenged racial stereotypes commonly attributed to black people, while reinforcing differences between races on the basis of alleged scientific evidence. I examine the ways in which Lefrou’s “raciology” influenced his studies on chimp physiology, pathology and psychology, and, inversely, how Lefrou used chimpanzee’s bodies in order to provide a better insight into local diseases. More specifically, I illustrate how Lefrou, using the chimp Tarzan, tackled the study of emotions in apes and the issue of reproduction in captivity and thereby humanized this very specific chimp. Finally, I show the ways in which, after independence in 1958, the Guineans constructed Tarzan as a martyr to colonialism, and eventually cast him as an emblem of the fledgling Republic of Guinea.