A compelling biography about a groundbreaking scientist and his controversial work, using rodent cities — rodentopias — to identify and examine the potential catastrophes that might befall human overpopulation.
Extinction is everywhere these days, mainly driven by unchecked human overpopulation, ecocidal abuses and runaway greed. But humanity itself should beware of their own impending doom.
What might humanity’s “end days” look like? The topic of the last days of humanity has occupied many dystopian and science fiction writers, but has not really captured the interest of scientists in a systematic and rigorous way. But there was one scientist, an ethologist (animal behaviorist) named John B. Calhoun, who was interested to find the answers to the many questions of what the extinction of humanity might look like. In his quest for answers, he conducted an 18-year long study with a ‘rodent utopia’ that he designed. His findings about population dynamics in his captive rat and mouse populations shocked most people in the mid-1950s to the early-1970s, making him a scientific celebrity although, strangely, most of his work is forgotten today.
Like with all scientific investigations, these experiments looked quite different at the beginning. After earning his PhD in zoology, Dr Calhoun joined the Rodent Ecology Project in Baltimore in 1946, whose original purpose was to eliminate rodent pests in cities. That project had limited success, partly because no one could figure out which aspects of rodent behavior, lifestyle, or biology to investigate and target. So Dr Calhoun decided to start hs studies from simple beginnings by setting up his first rodent utopia for Norway rats in the woods behind his house. He monitored the rodents over time to learn which factors drove their population growth.
It was then when Dr Calhoun noticed a curious thing: rat populations in a given area tended to stablize once a certain population number had been reached, even if the area had enough resources to support more rats. If Dr Calhoun added or removed some rats to see how the community would react, the rat population would adjust until it reached its original number.
This fascinated Dr Calhoun. He grew interested in learning about rodent behavior for its own sake and began crafting ever more elaborate and carefully controlled environments. But it wasn’t just the behavior of the rodents that interested him. Architects and civil engineers at the time were in the middle of vigorous debates about how to build better cities. For his part, Dr Calhoun proposed that urban design might be studied in rodents first and then extrapolated to human beings.
Dr Calhoun then decided to test his hypothesis by creating an experimentally perfect enclosure for mice, officially known as the Mortality-Inhibiting Environment for Mice, but unofficially and more colloquially known as “mouse heaven.”
Mouse heaven was a large enclosure — a 4½-foot cube — with everything a mouse could ever want or need: plenty of food and water; a perfect climate; reams of paper to make cozy nests; and 256 separate apartments that were accessible via mesh tubes bolted to the enclosure’s walls. Dr Calhoun also pre-screened the mice to eliminate any that were sick. Thus, free from disease, predators and other worries, a mouse could theoretically live to an extraordinarily old age in mouse heaven, without a single worry. And indeed, these enclosures initially did appear to be mouse (or rat) utopias, but as natural processes operated, these rodent utopias soon experienced overcrowding. This triggered abnormal behaviors in the rodent citizens, behaviors that Dr Calhoun referred to as “universal autism.”
Because so few juveniles died, huge hordes of mice would gather in the center of the enclosure. Dr Calhoun referred to them as “dropouts.” They were invariably covered with bites, and every so often huge fights would break out — vicious free-for-alls filled with biting and clawing that served no obvious purpose — just senseless violence. (In earlier rodentopias involving rats, instead of brawling, some dropouts became cannibals.) Other deviant behaviors also arose. Intriguingly, such maladjusted behaviors could spread like a contagion from mouse to mouse. Dr Calhoun dubbed this phenomenon “the behavioral sink.” Inevitably, mouse heaven became filled with mouse miscreants that triggered a population decline and eventual extinction.
After he had developed his methodologies and followed a few rodentopias to their natural conclusion, Dr Calhoun found that the outcomes of all these experiments were astonishingly consistent. Regardless of the scale of the experiments or whether they involved rats or mice, the same events occurred in each experiment:
- The rodents would mate and breed in large numbers.
- Followed by a reproductive leveling-off.
- Then violent or hostile anti-social behaviors became common.
- And last, the population would enter the death phase where it would trail off to extinction.
According to Dr Calhoun, there were two stages in the death phase: the “first death” was characterized by the loss of a reason for living beyond merely existing (such as the desire to mate, raise offspring, or establish a place in society), and the “second death,” which was the actual death and extinction of the rodentopia.
This 18-year series of experiments captured the imaginations of writers, behavioral biologists, psychologists, architects and the general public — although no one was quite sure what the findings actually indicated. In fact, Dr Calhoun reacted to the dystopias he created for rodents by envisioning utopias for humans. As his work progressed, Dr Calhoun seemed to focus intensely on the idea of a philosophy that would provide what humanity needed to continue to thrive despite the challenges posed by overpopulation. He also largely stopped publishing his research in scientific journals, preferring to publish in popular magazines, in part because of how his work overlapped with the overpopulation crisis, which was receiving a lot of media attention. Dr Calhoun even wrote an unfinished sci-fi novel on the topic.
You’ll find all this and much more in the book, Dr. Calhoun’s Mousery: The Strange Tale of a Celebrated Scientist, a Rodent Dystopia, and the Future of Humanity (University of Chicago Press; 2024: Amazon US / Amazon UK). Written by evolutionary biologist and historian of science Lee Alan Dugatkin, a professor and Distinguished University Scholar in the Department of Biology at the University of Louisville, where he studies the evolution of social behavior.
In this book, Professor Dugatkin does an excellent job of investigating, documenting and writing about Dr Calhoun’s life and work although he sometimes pursues the media coverage, conference talks and the intricacies of the experiments a little too far, in my opinion. (Thus, I found that the middle part of the book drags a bit.) Nonetheless, there is a lot of important, thought-provoking ideas in this book that I’ve not mentioned here.
Drawing on previously unpublished archival research and interviews with Calhoun’s family and former colleagues, Dugatkin offers a riveting account of an intriguing scientific figure. Considering Dr. Calhoun’s experiments, he explores the changing nature of scientific research and delves into what the study of animal behavior can teach us about ourselves.
I think Professor Dugatkin also missed an opportunity to present the social debates that Dr Calhoun’s work triggered and contributed to. For example: what was the main take-away from Dr Calhoun’s research? Were these experimental findings applicable to humans? Did Dr Calhoun’s darker predictions harm the public?
Nonetheless, I did enjoy this book and I think that many scientists and psychologists will be interested to read this long overlooked research, and dystopian and science-fiction writers will most certainly find it inspiring.
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