What would it take for a utopia to turn into a dystopia? For mice, it seems, the answer is crowding. Universe 25, the famous experiment by John Calhoun, started out as a seemingly perfect world for mice: a large square enclosure with limitless food and water, no predation or disease, plenty of bedding, and temperature control. The population started with 8 mice – four females and four males. By day 500 there were over 1,000 mice. By day 600, no young were surviving to birth, and the last conception was around day 920.
The mice of Universe 25 didn’t just die off after filling their habitat, they developed all sorts of strange behaviors. Some groups nest boxes were full to bursting while others were barely populated, reflecting what seemed to be a rigid hierarchy; large portions of the male population became withdrawn and seemed to form an underclass; and mothers started rejecting their children. Of particular note was a group dubbed “the beautiful ones”, who were completely uninterested in sex, fighting, or social interaction of any kind. They filled their days with eating, drinking, grooming, and sleeping, living in guarded spaces with lower populations.
What does Universe 25 say about the future of humanity? Unfortunately, this is where it gets complicated. Scientists disagree if the results seen in the mice can be used to draw conclusions about humans, with some studies supporting the detrimental effects of overcrowding and others showing no such effects at all. Worth noting is that the affects on the mouse population did seem to be entirely from crowding or excessive social interaction; mice kept in similarly utopic capitivity without crowding issues have no problem maintaining a healthy population (indeed, we wouldn’t be able to use lab mice otherwise, as they would quickly die out).
Still, developed nations are already showing declining birthrates – which might be good, or might be the first signs that humanity is heading towards the same sort of collapse as Universe 25. On can’t help but notices a comparison to overpopulated cities with small pockets of wealthier, more sparsely populated gated communities. Is humanity doomed?
Probably not. Humans are rather smarter than mice; critically, humans have access to birth control and the will to use it. Simply decreasing the birth rate so that the population remains steady at current rates would seem to solve the problem. If humanity wants to keep the population growing, we have the ability to spread out, first to rural areas, then into space. In the end, Universe 25 was a fascinating experiment, but it’s hard to tell how much it really tells us about the future for humans – and it certainly doesn’t mean that extinction is inevitable.