Archive · 15 Aug 2025
Universe 25: Overcrowding Experiment Leads to Mouse Extinction
Imagine a perfect world for mice: unlimited food, water, and a safe home.
That's what Dr. Calhoun created in his experiment, Universe 25.
He started with a few mice, and they multiplied quickly at first.
But as the population grew, things went wrong.
Mice started behaving strangely, fighting, neglecting their young, and isolating themselves.
Eventually, they stopped having babies, and the entire population died out.
This experiment showed how overcrowding and social problems can lead to collapse, even when resources are plentiful.
Dr. John B. Calhoun conducted the Universe 25 experiment in 1968.
The experiment involved a controlled environment for mice with unlimited resources.
The mouse population initially grew rapidly but later declined due to overcrowding.
Social breakdown occurred as mice exhibited abnormal behaviors, including violence and isolation.
The experiment concluded with the extinction of the mouse population within the enclosed habitat.
- Who
- Dr. John B. Calhoun conducted the experiment.
- What
- An experiment, Universe 25, designed to study the effects of overcrowding on mice.
- When
- The experiment began in 1968.
- Where
- At the US National Institute of Mental Health (NIMH).
- Why
- To study the effects of overcrowding and social breakdown on a population.
- Experiment Name
- Universe 25
- Researcher
- Dr. John B. Calhoun
- Starting Mice
- 8
- Environment
- Enclosed habitat with unlimited resources
- Peak Population
- Approx. 2,200 mice
- Outcome
- Extinction of the mouse population