Sociologists have challenged the discipline to account for and incorporate biological factors in their analyses. Heeding this call, this article asks how chimeras, a particularly puzzling biological organism, are being officially classified in the interrelated sites of endangered species preservation and the zoo. Based on a qualitative study of endeavors to clone endangered animals, I contend that biology alone cannot determine the classification of these interspecies organisms. Rather, categorizing chimeras requires metaphoric, schematic references to more familiar entities. Here culture and (...) biology are tools for classification, which has consequences for preservation practices and the materiality of endangered wildlife. Drawing on the sociology of culture, I show that positions on classification represent an intermediary space for interpreting the relationship between meaning and action in discourse elaboration. Building on the sociology of science and technology, I show the epistemological limitations of understanding the biological as an a priori factor. (shrink)