Everyone knows that rats are hosts of bubonic plague. But how did this knowledge emerge and develop? Contrary to what is generally imagined, rats were not associated with plague in scientific works before the mid-nineteenth century. And yet the association did not emerge, as we may expect, from the bacteriological revolution, but predates it. In this talk the lecturer proposes a new history of “how plague got rats” or how the disease came to be understood as a zoonosis spread by rats and their fleas; one that relies not on scientific “discovery” but on modes of relating plague and rats in complex and often incommensurable ways in the course of the third plague pandemic which, spreading to all inhabited continents by 1900, caused more then twelve million deaths. Whereas the established story is one of identification, this is one of relating; a story that explores the social, political and epistemic lives of the rat’s relation to plague, as catastrophic symbol, epidemic villain and epidemiological connector.