A few mice survived past weaning until day six hundred, after which there were few pregnancies and no surviving young. On day 560, a little more than eighteen months into the experiment, the population peaked at 2,200 mice and its growth ceased. Elsewhere, cannibalism, pansexualism, and violence became endemic. Other males, a group Calhoun termed “the beautiful ones,” never sought sex and never fought-they just ate, slept, and groomed, wrapped in narcissistic introspection. Lone females retreated to isolated nesting boxes on penthouse levels. Procreation slumped, infant abandonment and mortality soared. Left on their own in nests subject to invasion, nursing females attacked their own young. The victims of these random attacks became attackers. The failures and dropouts congregated in large groups in the middle of the enclosure, their listless withdrawal occasionally interrupted by spasms and waves of pointless violence. Normal social discourse within the mouse community broke down, and with it the ability of mice to form social bonds. With more and more peers to defend against, males found it difficult and stressful to defend their territory, so they abandoned the activity. Mice found themselves born into a world that was more crowded every day, and there were far more mice than meaningful social roles. More than six hundred mice now lived in Universe 25, constantly rubbing shoulders on their way up and down the stairwells to eat, drink, and sleep. So what exactly happened in Universe 25? Past day 315, population growth slowed. In Calhoun’s heaven, hell was other mice. The point was that crowding itself could destroy a society before famine even got a chance. This was, after all, “heaven”-a title Calhoun deliberately used with pitch-black irony. The only thing that was in short supply was space. But there was no scarcity of food and water in Calhoun’s universe. Vogt, Ehrlich, and the others were neo-Malthusians, arguing that population growth would cause our demise by exhausting our natural resources, leading to starvation and conflict. By 1972, the issue reached its mainstream peak with the report of the Rockefeller Commission on US Population, which recommended that population growth be slowed or even reversed.īut Calhoun’s work was different. After Ehrlich appeared on The Tonight Show with Johnny Carson in 1970, his book became a phenomenal success. In 1968, Paul Ehrlich published The Population Bomb, an alarmist work suggesting that the overcrowded world was about to be swept by famine and resource wars. The issue made the cover of Time magazine in January 1960. Pioneering ecologists such as William Vogt and Fairfield Osborn were cautioning that the growing population was putting pressure on food and other natural resources as early as 1948, and both published bestsellers on the subject. They were a warning, made in a postwar society already rife with alarm over the soaring population of the United States and the world. He had been building utopian environments for rats and mice since the 1940s, with thoroughly consistent results. As the name Universe 25 suggests, it was not the first time Calhoun had built a world for rodents. But its downfall was already certain-not just stagnation, but total and inevitable destruction.Ĭalhoun’s concern was the problem of abundance: overpopulation. To its members, the mouse civilization of Universe 25 must have seemed prosperous indeed. Those were the good times, as the mice feasted on the fruited plain. In their fully catered paradise, the population increased exponentially, doubling every fifty-five days. After 104 days of upheaval as they familiarized themselves with their new world, they started to reproduce. Heaven.įour breeding pairs of mice were moved in on day one. There were no predators, the temperature was kept at a steady 68☏, and the mice were a disease-free elite selected from the National Institutes of Health’s breeding colony. The Universe was cleaned every four to eight weeks. There was abundant clean food, water, and nesting material. That means 256 boxes in total, each capable of housing fifteen mice. Four horizontal corridors opened off each stairwell, each leading to four nesting boxes. Each wall had sixteen vertical mesh tunnels-call them stairwells-soldered to it. The first 37 inches of wall was structured so the mice could climb up, but they were prevented from escaping by 17 inches of bare wall above. The Universe took the form of a tank, 101 inches square, enclosed by walls 54 inches high. Every aspect of Universe 25-as this particular model was called-was pitched to cater for the well-being of its rodent residents and increase their lifespan. Calhoun detailed the specifications of his Mortality-Inhibiting Environment for Mice: a practical utopia built in the laboratory.

How do you design a utopia? In 1972, John B.

Universe 74 rat utopia