🚨 The Universe 25 Experiment — The Mouse Utopia That Turned Into Hell In the late 1950s, scientist John Calhoun created what seemed like paradise for mice: unlimited food, fresh water, perfect climate, no predators, and endless resources. For a while, the colony flourished. But once the population reached around 600, everything began to collapse in ways no one expected. Social order broke down. Dominant males turned violent. Mothers stopped caring for their young. Random attacks became common.