Experiment “Universe-25”: as a paradise became hell !

For the population of mice within a social experiment created a haven: unlimited supplies of food and water, lack of predators and disease, enough space for breeding. However, the entire colony of mice died. Why did this happen? And what are the lessons of this should bring mankind?


American scientist ethologist John Calhoun held a number of fascinating experiments in the 60-70 years of the twentieth century. As an experimental D. Calhoun invariably chose rodents, although the ultimate goal of the research has always been predicting the future for human society. As a result of numerous experiments over the colonies of rodents Calhoun has formulated a new term, behavioral sink» (behavioral sink), indicating a transition to destructive and deviant behavior in terms of overpopulation and overcrowding. His research, John Calhoun acquired a certain fame in the 60s, as many people in Western countries, is experiencing a post-war baby boom, began to think about how overpopulation affect public institutions and for each person in particular.



His most famous experiment made us think about the future of an entire generation, he held in 1972 in conjunction with the National Institute of Mental Health (NIMH). The purpose of the experiment Universe-25″ was to analyze the effect of population density on the behavior patterns of rodents. Calhoun built a paradise for mice in the laboratory. Was created by a tank the size of two by two meters and a height of five feet, where guinea could not get out. Inside the tank to maintain a constant comfortable temperature for mice (+20 ° C), was present in abundance of food and water, created numerous slots for females. Each week, the tank is cleaned and maintained in constant state of cleanliness, had taken all the necessary precautions: eliminates the appearance of predators in the tank or the occurrence of massive infections. The experimental mice were under constant supervision of veterinarians, their health status is constantly monitored. System for ensuring food and water was so thought that 9500 mice could eat at the same time without experiencing any discomfort, and 6144 mice consume water, and without experiencing any problems. Spaces for mice was more than enough, the first problem of lack of shelter could only arise when the population of more than 3840 individuals. However, such a large number of mice had not been in the tank, the maximum size of the population at levels 2,200 mice.
The experiment started with a moment of space inside the tank four pairs of healthy mice, which took quite a bit of time to get used to, realize what a mouse in a fairy tale they get, and start multiplying rapidly. Calhoun called the period of development of phase A, but since the birth of the first Young began the second stage of B. This is the stage of exponential growth of population in the tank under ideal conditions, the number of mice doubled every 55 days. Starting with the 315 days of the experiment the rate of population growth has slowed considerably, and now the number has doubled every 145 days, which marked the entry into the third phase C. At this point in the tank were about 600 mice, formation of a certain kind of hierarchy and social life. Become physically less space than before.
There was a category of “excluded”, who were being driven into the center of the tank, they often become victims of aggression. To distinguish a group of “outcasts” could be bitten by the tails, tear out hair and traces of blood on the body. Les Miserables consisted primarily of young individuals, who did not find for themselves the role of the social hierarchy in the mouse. The problem of lack of appropriate social roles was caused by the fact that under ideal conditions the tank mice lived long aging mice do not make room for young rodents. So often aggression was aimed at a new generation of individuals born in a tank. After the expulsion of the males were broken psychologically less showed aggression, unwilling to defend their pregnant females and to perform any social roles. Although they attacked periodically or on other individuals of the society “Les Miserables”, or on any other mice.Female, preparing for birth, became more and more nervous, as a result of the growth of passivity among males, they become more vulnerable to random attacks. As a result, the female began to show aggression, often fighting, protecting offspring. However, paradoxically, aggression was not directed only at others, not less aggressive show in relation to their children. Often females killed their young and climb into the top slot, becomes aggressive and hermits refused to reproduction. As a result, the birth rate has dropped substantially, and the mortality rate of young animals reached significant levels.Soon the last stage of the existence of the mouse paradise D phase or the phase of death, as its called John Calhoun. The symbol of this stage is the emergence of a new category of mice, known as “beautiful”. These include males, showing uncharacteristic behavior for the species, refuses to fight and fight for females and territory, shows no desire to mate prone to passive lifestyle. “Beautiful” only ate, drank, slept, and purified their skins, avoiding conflicts and perform any social functions. Like they got the name because unlike most of the other inhabitants of the tank on their body were no signs of brutal battles, scars and hair torn out, their narcissism, and narcissism have become legendary. The researchers also struck by the lack of desire in “beautiful” to mate and reproduce, among the latest wave of births in the tank “beautiful” and single females who refuse to breed and runs in the top slot of the tank, became the majority.
The average age of mice in the latter stages, the mouse was paradise 776 days, 200 days exceeds the upper limit of childbearing age. Mortality of young was 100%, the number of pregnancies was negligible, and soon was 0. Endangered mouse practiced homosexuality deviant and inexplicably aggressive behavior under conditions of excess of vital resources. Cannibalism flourished while plentiful food, females refused to educate the young and killed them. Mice rapidly died out in 1780 on the day after the start of the experiment died last occupant mouse paradise.”In anticipation of such a catastrophe, D. Calhoun using colleagues Dr. H. Marden held a series of experiments in the third stage of death phase. From the tank were removed a few small groups of mice and relocated to an equally ideal conditions, but also in terms of minimum population and unlimited space. No overcrowding and intraspecific aggression. In fact, the “beautiful” and female lone were recreated the conditions under which the first 4 pairs of mice in the tank exponentially multiplied and created a social structure. But to the surprise of the scientists, “beautiful” and single females did not change their behavior, refused to mate, reproduce and perform social functions related to reproduction. As a result, there were no new pregnancies and mouse died of old age. These same results were observed in all groups resettled. As a result, all the experimental mice died while under ideal conditions.

John Calhoun created based on the results of the experiment the theory of two deaths. First death” – is the death of the spirit. When the newborn was not particularly find a place in the social hierarchy mouse paradise,” that there has been a lack of social roles in ideal conditions with unlimited resources, there was an open confrontation and young adult rodents, increased level of unwarranted aggression. The growing size of the population, an increase in crowding, increased levels of physical contact, all of this, according to Calhoun, led to the emergence of individuals capable of only simple behavior. In the context of an ideal world, the security of the abundance of food and water, the absence of predators, most individuals only ate, drank, slept, looked after him. Mouse – a simple animal, for him the most complex behavior – is the process of courting the female, reproduction and parental care, protection of the territory and the young, participate in the hierarchical social groups. From all of the above broken psychologically mouse refused. Calhoun calls a similar rejection of complex behavioral patterns first death” or “death of the spirit.” After the onset of the first death, physical death (“second death” in the terminology of Calhoun) is inevitable and is a matter of a short time. As a result of the “first death” a significant part of the population the whole colony is doomed to extinction even in a “paradise”.
Once Calhoun asked about the reasons for the emergence of a group of rodents “beautiful”. Calhoun drew a direct analogy with the man, explaining that a key feature of the person, his natural destiny – is to live in conditions of pressure, tension and stress. Mouse, give up the fight, choosing unbearable lightness of being turned into autistic handsome”, capable of only the most primitive functions of the absorption of food and sleep. Of the total complex and requires hard handsome” and refused, in principle, become not capable of such a powerful and complex behavior. Calhoun draws parallels with many modern men, capable of only the most routine, everyday actions to maintain physiological life, but the spirit was dead already. Resulting in the loss of creativity, the ability to overcome and, most importantly, to be under pressure. Refusal to accept numerous calls an escape from stress, from a life full of struggle and overcoming – a “first death” in the terminology of John Calhoun, or death of the spirit, which is inevitably comes the second death, this time the body.Perhaps you have a question, why the experiment D. Calhoun called “Universe-25″? It was the twenty-fifth attempt scientist to create a paradise for mice, and all prior resulted in death of laboratory rodents
Author: Vladimir Shevelev

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