When rabbits became humans (and humans, rabbits): stability, order, and history in the study of populations

“Population” is often a significant unit of analysis, and a point of passage for facts and models moving between the natural and social sciences, and between animals and humans. But the very existence of a population is a “fact” fraught with challenges: What distinguishes a population from an economy, an ecosystem, a society? Are populations simply memory-less aggregates of solitary individuals, or do they constitute groups with unique histories and agency? Looking at how populations of humans and populations of rabbits were thought of in terms of one another, this paper examines several interlinked episodes in the history of “population” as an organizing concept in 20th century science, tracking the transfer of facts from rabbit populations to human populations (and vice versa) through economics, infectious disease modelling, and macro-histories. What happens when rabbits become human, and when humans become rabbits?