The Rat Utopia Experiment

About

The Rat Utopia Experiment refers to a series of overpopulation studies conducted by ethologist John B. Calhoun between 1958 and 1962 on brown rats. In these experiments, Calhoun and his researchers created enclosed spaces called "rat utopias" where rats were provided unlimited access to food and water, allowing their populations to grow without constraint. Through these observations, Calhoun developed the term "behavioral sink" to describe the collapse in behavior resulting from overpopulation. He introduced this concept in a February 1, 1962, Scientific American article titled "Population Density and Social Pathology." Later, Calhoun conducted similar experiments on mice from 1968 to 1972, further exploring the effects of crowding on animal behavior. The work produced by these experiments has since become widely used as an animal model for understanding societal collapse and has significantly influenced both urban sociology and psychology as academic disciplines.