The infamous Piltdown hoax offers an excellent opportunity to study how a figure that straddled the human—animal boundary (both figuratively in its positioning as a “missing link,” and literally given its post-hoax status as a modern human skull and a modern orangutan jaw) was made to fit dichotomous understandings of it. The process of making this figure human reveals how scientific claims in the disputed border zone between humans and non-human animals are shaped by the cultural themes upon which the division stands. Nationalism, race and species classification became enmeshed in the efforts to lead Piltdown from its liminal position to more conceptually stable ground. The result was a stretching of human-ness, that brought Piltdown closer to us whilst modern-day “savages” were moved further away. The paper's theoretical framework shifts Gieryn's boundary-work model from an ontology of culture to an ontology of nature. Transplanting Gieryn's model in this way is useful not only because of the parallels specifically between the science—culture and human—animal boundaries, but also as it serves as a reminder of the strong relationship between the categorization of the social and natural worlds.