(Part 1/3) Universe 25 / Mouse Utopia : The Study

Posted on Posted in Insights, Thoughts
Universe 25 / Mouse Utopia

I recently witnessed the famous Mouse Universe experiment by John Calhoun and this compelled me writing and sharing my thoughts. One of his many published studies, grimly titled “Death Squared: The Explosive Growth and Demise of Mouse Population” attempted exploring curiosities at establishing a “Perfect” world. A “Universe” with unlimited (given) Resources.

The aim of the study was seemingly simple. To study effects of overcrowding in mice population despite abundance of food, water. And to assess their behavioural markers; social, territorial, reproductive and maternal instincts included.

Enter the “Perfect” Universe (for mice).

Enclosed within this Utopia – were numerous “apartments” capable for supporting up to 4,000 mice “citizens”. Litters and all waste were cleaned (voluntarily by humans obviously) ensuring no bio-chemical threat confounder. According to the study the overall food and water availability / prepared abundance was so immense; theoretically it sufficed to cater the population count of 9,500. The water supply was theorised to cater up to 6,144 citizens. 

All social & mating observations; from initiation to upbringing were assessed throughout the (almost) 1600-day written observational records.

Given the mixed receptions – the possibility of these mice’s behavioural analogy towards applied human concerns still remain disputable for decades on, even to this day. Reading the actual published paper itself still remains highly advisable because Calhoun himself attempted to address most (though not all) skeptics and counter arguments.

The Four (4) phases or overall “evolutions”.

There are Four as accordingly to the original paper ~ stages or evolutions throughout this fascinating study.

Strive, Growth, Stagnation, and Death.

Universe 25 / Mouse Utopia
Jeremy Bishop @ Unsplash

Phase A “Strive”.

The “Genesis” in this Universe began with introducing four pairs of “Adam and Eves”. The first ever (mice) citizens freely roaming the “planet”. This marked the first of the four phases or evolutions – of which Calhoun titled as “Strive”.

This was simply a phase for exploration and adjustments within the Universe’s environment or the “apartments”. As well ~ where and how to access the consumable resources (food + water). Early settlements appear to formed as signs of territorial divisions. However, social dominance or conflicts amidst these early state of population – were seemingly non-significant.

A brave new world began. The curtain was opened.

Phase B – “Growth”.

Universe 25 / Mouse Utopia
Davide Ragusa @ Unsplash

An exponential increase in populations were noted. Signs of territorial boundaries seemed established.

The growth was immense; almost doubling over previously recorded quota on every 55 days. Mating events successfully occurred as soon as sexual maturity age were reached.

Throughout days #86 to #338 saw a period of territorial division/s. Despite food + water supply were scattered as evenly possible – some areas of the Universe seemed distinctly more concentrated in sexual mating events than others. In other words, some areas appeared “lonely”.

Dominance Social hierarchy also appeared to be developing. As Calhoun hypothesized – this is rationalised by how “active” the male population were at initiating all sexual reproductive instincts. He termed this “Social Velocity”.

These “active” males appears to be more localised in certain parts. Mostly on the south western side of the Universe.

The “older” aged population however on the other hand appeared to be congregating on the complete opposite corner (North Eastern of the Universe). This area produced the fewest offsprings compared to its opposite “younger” region. As quoted straight from the study: “The north east brood group produced only 13 young in 252 days where as the opposite South West brood group produced over eight times as many, 111.” (Calhoun, J. 1973).


Phase C – “Stagnation”.


Universe 25 / Mouse Utopia
Peter Lewicki @ Unsplash

Overall population began to plateau. In some areas they declined. 

Increasingly “violent” activity seemed arising. Possible reason for this was for the dominance fought amongst the male (and later on – females). Rates of injuries and deaths amongst the lesser active and the lesser dominant males were increasing.

The growing numbers of “passive” males – especially noted by the scarring wounds on their tails  congregated further – towards  the very epicentre of the entire Universe.

Yet overtime – the “centre” eventually became a confusing mix of the prior passive to now then turned – violent disruptions against one another.  

Maternity roles; whom the females responsibly nurtured their young optimally – seemed increasingly abandoned & neglected. As noted by Calhoun:

“Females transported their young to several sites, during which process some where abandoned. Many litters of a young age on one survey disappeared before the next survey….Such abandoning of young following survey disturbance is a particularly sensitive index of dissolution of maternal behaviour.” (Calhoun, J. 1973)

Almost all nesting sites that were once protected – now ploughed in the process due to the overlapping invasions. Throughout this Phase, signs of aggression or of overall hostility of the females increasingly were matching to that of their male cohort. 

Whilst chaos persisted in the background – few appears to take refuge elsewhere on the solitary spaces. 

These “survivors” were later then named by Calhoun – as “The Beautiful Ones”.


Phase D – “Death”.


Universe 25 / Mouse Utopia
David Cohen @ Unsplash

From day #600 onwards; more deaths were observed than births.

Any attempts at increasing stable population growth – seemed futile. Mating events now became disruptive and maternal behaviours grew more unusual. Homosexuality and/or even familial incests began proliferating in large attempts. Only a few numbers of births occurred, but this was greatly offsetted by the rising number of deaths amongst almost all mice groups, irrespective of locale.

Perhaps the most interesting, were the rise (as well as solitary deaths) of the passive and non-warring mice whom Calhoun called “The Beautiful Ones”. These mice were not only exemplary of hoarding and overly protective – of their simplistic living pattern (eating, “grooming”, and sleeping; on constant repeat). But curiously – their sexual reproductive instincts / desires – seemed muted. 

Neither did they evoke – random acts of violence either. What appeared extraordinary is their “beautiful” appearance. Bleached white skin, gentle furs, alert and bright red eyes. Free from battle-scars and/or  wounded tails.

Meanwhile elsewhere ~ an increasingly premature abandonment from mothers and their children from the previous Phase (“C”) continued. Any signs of traditional raising patterns were almost nilDespite new (very few) births were seemingly successful; the offsprings immediately were abandoned by mothers.

The last known recorded conception was noted in Day #920.

From there on; all inhabitants of Universe 25  proceeds to decline rapidly. Seemingly headed for total extinction. 

Mortality rates increased as compounded by the (solitary) deaths of The Beautiful Ones from old age. So too combined with premature deaths from helpless exposure to collateral invasions further adding to the  toll. 

Amidst all that, calamity and violence continued in the background. “The Beautiful Ones” – continued subsisting in solitary spaces. Their fates headed towards little else – than towards solitary deaths, of old age.

The dawn of day #1588 – was marked as the final day of Universe 25. 

An “inexorable decline”; as Calhoun wrote. What was left and recorded as final population count on this day – were just twenty-three (23) females and four (4) males.  

…The curtain was closed.


Universe 25 / Mouse Utopia
Elijah Flores @ Unsplash

The theory behind the decline – “Behavioural Sink” & its Critic/s

Multiple theories and hypothesis still remains to this day actively debated. Among them was largely a critique on Calhoun’s causation hypothesis known as the “Behavioural Sink”. In short definition – through concentrated population density in any given localised area alone; leads to an observed hopelessness or oblivious irrationality.

Hence “Behavioural Sink” suggested that environmental factors led to the mice’s destined demise.

Excess Totalitarian “In”-clusivity VS embracing “Ex”-clusivity.

A notable critique to the Behavioural Sink however was raised by Psychologist Jonathan Freedman. He hypothesized it was not so much about the physical aspect of “overcrowdedness” that played the biggest causality at decimating the mice population. But rather – the already seemingly enforced expectation – for social in-teractivity than welcoming social ex-clusivity.

He hypothesized that perhaps Totalitarian in-clusivity was seemingly encouraged. Given by overlapping (and warring) conquests inbetween divisions for total dominance.

This may seem difficult to understand. But another likewise critique by Dr. Edmund Ramsden summed it up in two part/s:

“…Moral decay could arise not from density, but from excessive social interaction,”
and (as continued) –
” It was the unwanted unavoidable social interaction that drove even fairly social creatures mad,” (Ramsden, E. 2008).

Notice the word “unwanted”. And “unavoidable”. This hints that there appears to be a question of “choice”.

Consider those who survived and found solace in sparse distant locale’s; aka “The Beautiful Ones”. Perhaps these behaviours – were evolutionary instinct as means to evade or avoid the totalitarian “In”-clusivity. Or at least, it appears to be a chosen reaction to not participate amidst the violence.

Noting this, Calhoun’s colleague tried physically relocating them into another Universe for any hopeful reproduction with “adequate sex partners” (page 85). Yet failed miserably, as cited;

“Even placing them with adequate sex partners of the opposite sex, that had matured in uncrowded conditions, also gave very little indication of retention of any adequate reproductive behaviour.” (page 85).

Once again, the above finding speculates ~ that the Beautiful Ones rejects (by “choice”, once again) on anything new than their own homeostatic solidarity. Even when inadvertently placed in a fresh new environment for mating opportunities led these mice in confusion, awkwardness and hesitance to reproduce.

Matthew Hamilton @ Creative Commons
Matthew  Hamilton @ Creative Commons

…So what are “my” thoughts?

It depends on what context this question is aimed at. If it were me being squarely asked whether I believe the Behavioural Sink theory holds applicably true for humans? I’d say both yes and no.

It is impossible to curate my thoughts all in one writing. Hence, read on here to proceed for part 2 whereby I will be splitting my thoughts into several points. 

Leave a Reply

Your email address will not be published. Required fields are marked *