• Isaac Vitorino

Calhoun’s Universe 25 and Contemporary Society

Updated: Jul 25

John B. Calhoun was an American ethologist and behavioural researcher who focused mostly on how population density could affect behaviour. One of his most famous works regarding this subject was carried out in the 1960s and is commonly known as the mice utopia or Universe 25 experiment. In this article, I will be going through this particular piece of Calhoun’s work and attempt to establish a few parallels between the results of this experiment and life in contemporary society.


The reason why mice were used in this study is due to the incredible similarities that mice share with humans. Almost all of the genes in mice share functions with the genes in humans, and seeing as humans and mice share various similarities in both development and the functioning of their bodies from hormonal levels to reproduction and various systems (digestive, respiratory, etc) mice’s physiology has long been used to study various aspects pertaining to humans, such as testing medication for various diseases. Furthermore, the amount of information gathered around rats and mice, and their relatively short lifespans, make them the model choice for biomedical research.

Now that the importance of rats and mice for experiments has been established, now is the time to go into detail on the nature of Calhoun’s work. The mouse utopia he created consisted of “a tank 101 inches square, enclosed by walls 54 inches high. The first 37 inches of wall was structured so the mice could climb up, but they were prevented from escaping by 17 inches of wall above”, so there would be limited space. However, and most importantly, all of the mice’s needs, be it water, food and shelter were guaranteed: “Each wall had sixteen

vertical mesh tunnels – call them stairwells – soldered to it. Four horizontal corridors opened off each stairwell, each leading to four nesting boxes. This means 256 boxes in total, each capable of housing fifteen mice”. With the absence of predators and with the first few mice chosen to be put into the tank disease-free and handpicked due to their prime physical condition, this scenario would be considered to be heaven on earth for the mice.

As far as the experiment itself, it seemed to be a success at first. For the first 315 days, there was a steady population growth with increased the numbers of mice in Universe 25. However, since their daily activities consisted of eating, drinking and sleeping, “Mice found themselves born into a world that was more crowded every day, and there were far more mice than meaningful social roles”. Seeing as the existence of predators and dangerous externalities was not a factor in this experiment, male mice found it increasingly more difficult and stressful to defend their territory and thus started withdrawing from society at ever-larger numbers. With this withdrawal, discourse within the community started to break down, eviscerating social bonds.

“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”. The mice who were still inserted into societal norms but were attacked by these groups eventually became attackers themselves, leaving females vulnerable to attack as well, something which triggered a seemingly irrational response by them which was to attack their children. The eventual consequences of Calhoun’s Universe 25 were the following: “Procreation slumped, infant abandonment and mortality soared. Lone females retreated to isolated nesting boxes on penthouse levels. 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. Elsewhere, cannibalism, pansexualism, and violence became endemic”.

In Calhoun’s own words, “Many female rats were unable to carry pregnancy to full term or to survive delivery of their litters if they did. An even greater number, after successfully giving birth, fell short in their maternal functions. Among the males the behaviour disturbances ranged from sexual deviation to cannibalism and from frenetic overactivity to a pathological withdrawal from which individuals would emerge to eat, drink and move about only when other members of the community were asleep.” What seemed like an environment able to produce heaven on earth, had become hell.


The population peaked at 2,200 mice on day 560. 40 days later, there were no pregnancies and no surviving young population. In summary, “many of the mice that could still conceive, such as the “beautiful ones” and their secluded singleton female counterparts, had lost the social ability to do so. In a way, the creatures had ceased to be mice long before their death—a “first death,” as Calhoun put it, ruining their spirit and their society as thoroughly as the later “second death” of the physical body”. Calhoun carried out a few more researches with mice, tweaking a few of the environmental variables in an attempt to influence what seemed to be a constant outcome; in this effort, however, he was unsuccessful. All of the environments he created with the intent of providing the mice with a peaceful and plentiful environment all degenerated into hyper-aggressive behaviour, erratic sexual behaviour followed by asexuality, withdrawal from sexual activity at all levels, and extinction.


As it regards human beings, Calhoun was absolutely certain that the same scenario could apply to them. Regarding overpopulation and an ever increasing number of people for an ever decreasing amount of significant social roles, his own words explain the outcome: “only violence and disruption of social organization can follow (…) Individuals born under these circumstances will be so out of touch with reality as to be incapable even of alienation. Their most complex behaviours will become fragmented. Acquisition, creation and utilization of ideas appropriate for life in a post-industrial cultural-conceptual-technological society will have been blocked”. The term behavioural sink was created by Calhoun to describe this scenario.


It is hard to reach a definitive conclusion on if Calhoun was completely right, and there is certainly an argument to be made in favour of human intelligence and self-awareness obviously surpassing that of mice, even if there are sensible similarities between the species. However, there are a few aspects regarding modern societies, particularly those of first world countries, that are quite frankly similar to the catastrophic Universe 25. Here follow a few examples:

· In general, most first world countries are in a demographic winter after a period of steady population growth, just as it happened with Universe 25.

· The withdrawal of males from mice society is also eerily similar to hikikomori men in japan (teens and young adult men in Japanese society who withdraw from society to pursue personal hobbies) and many more young men across the West.

· The gangs of mice dropping out of society can also have our modern equivalent, in the form of some groups which compose the so-called online manosphere, such as MGTOWs or Incels.

· The erratic sexual behaviour registered by the mice can also find its equivalent in our societies in the form of the continuous loosening of sexual morality.

· Lower fertility rates, increasing numbers of mothers killing their children and acceptance of practices such as abortion are also easy to relate to the decreasing level of maternal behaviour in the female mice studied.


It is impossible to know if we are bound to follow the path that leads to the apocalyptic scenario that Calhoun predicted. However, his theories about the dangerous level of overpopulation and the adverse effect it can have on society have surpassed in both quality and durability the work of others who had mostly focused on how overpopulation might have destroyed all resources. Most of those in Calhoun’s time who had predicted shortage of resources in our lifetimes have been proven to be spectacularly wrong; Calhoun, however, not only is yet to be proven wrong, but the results of his experiments seem to have equivalents in the form of some behaviour types in our society. If his experiment with mice fully correlates to human behaviour, however, is yet to be seen, and only time will tell if human conscience can trump the degeneration of our behaviour at a primal level.

The Politician Independent Newspaper, created in 2020