it seemed as though it is an alarming results
below is of it's outcome:
An interesting example of social breakdown in a crowded population of experimental animals was created by John Calhoun at the National Institutes of health in the late 1960's and early 1970's.1 Calhoun created a "Utopian environment" for mice to study the effect of exponential population growth on social behavior.
The mouse environment was a 101-inch-square pen with 54-inch-high walls, constructed with nesting boxes on the walls to maximize breeding space. The floor of the environment was covered with ground corn cob, and paper strips were providing as nesting material. Calhoun provided adequate food and water in regularly spaced hoppers. The room temperature was relatively stable during the years of the experiment.
Calhoun put four male and four female laboratory mice into this space on July 9, 1968. The first 104 days, which Calhoun called "Phase A," were characterized by social turmoil as the mice adjusted to their new environment. The first litter was born at 104 days, and the population began to expand exponentially, doubling every 55 days. This was "Phase B." At day 315, with a population of 620 weaned mice, the population growth abruptly slowed to a doubling time of 145 days; this was "Phase C."
At this time, the social structure began to deteriorate and violence levels increased.
... there was no room for emigration. As the unusually large number of young gained adulthood, they had to remain, and they (contested) for roles in the filled social system. Males who failed withdrew physically and psychologically; they became very inactive and aggregated in large pools near the centre of the floor of the universe. From this point on they no longer initiated interaction with their established associates, nor did their behavior elicit attack by territorial males. Even so, they became characterized by many wounds and much scar tissue as a result of attacks by other withdrawn males.... Female counterparts of these withdrawn males tended to withdraw to higher level boxes that were less preferred by females with litters. Such females were not characterized by the violent aggression of the withdrawn males.
Mouse fertility decreased, baby mice were abandoned, fetuses spontaneously aborted, and maternal behavior disappeared. The dominant male mice could no longer defend all their territory from the masses of males, and began less and less to defend the nesting sites they were associated with. Thus, the nesting sites became exposed to "invasion," and in response, the nesting females became aggressive, taking over the role of the dominant males. The aggression carried over to their offspring: the mothers attacked their young, wounded them and forced them to leave the nest early. All social interactions between the mice were of short duration and superficial, and no real courtship or parenting behavior could develop.
The population peaked at 2,200 mice on day 560. No baby mice survived infancy after day 600, and the population began a decline. The last conception was about day 920. An attention toward the end to add some healthy mice failed to rejuvenate the population. Calhoun reported that on June 22, 1972, there were only 122 survivors.
