Classification in eighteenth-century natural history was marked by a battle of systems. The Linnaean approach to classification was severely criticized by those naturalists who aspired to a truly natural system. But how to make oneself nature''s spokesman? In this article I seek to answer that question using the approach of the French anthropologist of science Bruno Latour in a discussion of the work of the French naturalists Buffon and Cuvier in the eighteenth and early nineteenth century. These naturalists followed very (...) different strategies in creating and defending of what they believed to be a natural classification in zoology. Buffon failed, whereas Cuvier''s work appeared to be very successful. My argument will be that, to explain Buffon''s failure and Cuvier''s success, we should not focus on the epistemological or theoretical concerns and justifications of these naturalists, but on the concrete and heterogeneous means or tools through which animals were mobilized, stabilized and combined into ever more comprehensive systems of classification. (shrink)