An alternative view point : https://www.lrb.co.uk/the-paper/v47/n13/jon-day/the-beautiful-ones

The accuracy of Calhoun’s observations about rat sociology, still less their relevance to human society, remains a matter of debate. Even at the time he was criticised for the methodologies of his experiments (one colleague at NIMH told him that ‘there are so many variables in your research that you can’t possibly draw any conclusions about anything’).

Many of the behaviours he considered ‘aberrant’ – cannibalism, aggression, homosexual mating – are not uncommon in rodent society. As both books acknowledge, his experiments have never been successfully replicated by other researchers, and wild colonies of rats don’t seem to display any of the personality types he so vividly described. He rarely published in mainstream scientific journals, saying that his concerns were so pressing that he didn’t have time to wait for peer review.

It seems plausible that Calhoun was responsible for creating the conditions for population collapse. He only cleaned out Universe 25 every six to eight weeks; disease and parasitism could account for many of the phenomena he thought were due to mere proximity. It can’t have helped that, other than the ladders and ramps, the Universes didn’t provide much in the way of stimulation. Calhoun thought of his rat cities as utopias, but they seem more like well-stocked prisons. No wonder they didn’t bring out the best in the inmates.

I generally raise eye brows any time the dangers of overpopulation come up, as it always a concern of eugenicists. These sorts of research studies are constantly looking for data that confirms beliefs they already held, and they never want to look any further in what the root causes are. The foregone conclusion is always demanding population control, followed with the healthy dose of “I’m just asking questions!”.