The Universe 25 Experiment
Universe 25: Calhoun's mouse Eden with unlimited resources. Population peaked on day 560, then collapsed via abnormal behavior. Extinction by day 1780 —illustrating "behavioral sink" despite abundance.
In Universe 25, overcrowding led to "behavioral sink": social withdrawal, hyper-aggression, neglect of young, sexual deviance, and role failure, causing total population collapse despite abundant resources.
In Universe 25's behavioral sink: males withdrew, hyper-aggressed, or became passive "beautiful ones." Females, defending nests, fought males until exhausted, then neglected young. That is when the irreversible collapse—despite resources—happened.
Three distinct categories of males emerged:
- Hyper-aggressive — violent, attacking indiscriminately.
- Withdrawn/passive — socially disengaged, avoiding interaction.
- "Beautiful ones" — obsessively grooming, non-reproductive, aloof.
Dubbed as ''rat Eden'' (hint to 2,400 years ago or so).
25 stands for the number of times the experiment was repeated, with identical results.
Day 560 = population peak.
Day 920 = last conception.
Day 1780 = extinction day (May 23, 1973)
The total duration was four years and ten months.
1946 =day 1
1970s - 1980 - peak population - around day 560 of the experiment.
1990s - 2020 = decline
Extinction Timeline: 2147 ± 200 Years