John B. Calhoun

John B. Calhoun As modern living and the climate crisis create ever greater stress in our habitat, consideration of Calhoun's findings on habitat stress and extinction may well be in order.

John B. Calhoun's famous rodent habitat studies documented that even while providing all requirements for a population, stress (which he induced through overcrowding) will always lead to extinction, with notable exhibition of bizarre and self-defeating behaviors along the way, and especially towards the end of the habitat's cycle. A few videos and articles are below, with more at https://johnbcalhoun.com

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John B. Calhoun: The ‘mad egghead’ who built a mouse utopia
John Calhoun 1971 small Standing before the Royal Society of Medicine in London on 22 June 1972, the ecologist turned psychologist John Bumpass Calhoun, the director of the Laboratory of Brain Evolution and Behavior at the National Institute of Mental Health (NIMH) headquartered in Bethesda Maryland [said] “I shall largely speak of mice, but my thoughts are on man” ... what began as a rodent utopia – where mice had sumptuous accommodations, all the food and water they could want, and were free from the twin scourges of disease and predation – over time degenerated into a mouse hell [which] had mice displaying a suite of aberrant behaviours ... Even if mice were [then] placed into another mouse apartment block with a much lower density of residents, Calhoun explained, they still showed these aberrant behaviours ... Some of the society members knew of Calhoun’s article in Scientific American a decade earlier [and] Time magazine [wrote] “even if some way can be found to feed the onrushing millions [of humans], they may still face a psychic fate similar to the one that befell Dr John Calhoun’s white mice” ... Work on population dynamics and behaviour has changed radically since Calhoun undertook his experiments. [Yet] Calhoun’s work lives on in our collective consciousness and has remained a subject of fascination in popular culture.
https://www.theguardian.com/science/2024/nov/21/the-mad-egghead-who-built-a-mouse-utopia-john-b-calhoun

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John B. Calhoun and the Rats of N.I.M.H.

The 1982 animated feature "The Secret of N.I.M.H." was based on a children's book inspired by real research being done at the National Institute of Mental Health. John B. Calhoun's research into "crowding" and "behavioral sink" affected fields from psychology to architecture, and tapped into the fears of the era. It is history that deserves to be remembered.
https://www.youtube.com/watch?v=3Kqti3tDz-M

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The urban animal: population density and social pathology in rodents and humans
Calhoun placed several rats in a laboratory in a converted barn where - protected from disease and predation and supplied with food, water and bedding - they bred rapidly. The one thing they were lacking was space ... Unwanted social contact occurred with increasing frequency, leading to increased stress and aggression. Following the work of the physiologist, Hans Selye, it seemed that the adrenal system offered the standard binary solution: fight or flight. But in the sealed enclosure, flight was impossible. Violence quickly spiralled out of control ... Their numbers fell into terminal decline and the population tailed off to extinction ... At the experiments’ end, the only animals still alive had survived at an immense psychological cost: asexual and utterly withdrawn, they clustered in a vacant huddled mass. Even when reintroduced to normal rodent communities, these “socially autistic” animals remained isolated until death. In the words of one of Calhoun’s collaborators, rodent “utopia” had descended into “hell”.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2636191

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Universe 25 - John Calhoun's NIMH experiment

Leading up to 1972, John B Calhoun conducted a series of experiments under the guidance of the National Institute of Mental Health (NIMH). In these experiments Calhoun observed rats and mice populations coping with various living situations and environments. These experiments culminated in Universe 25; a mouse utopia which lasted 600 days and ended in the extinction of all inhabitants.
https://www.youtube.com/watch?v=7CXj0AGuh4c

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Death Squared: The Explosive Growth and Demise of a Mouse Population by John B Calhoun MD
Proceedings of the Royal Society of Medicine Volume 66 January 1973
John Calhoun's presentation on Universe 25 (one of his last) and what this might mean for humans. "For an animal so simple as a mouse, the most complex behaviours involve the interrelated set of courtship, maternal care, territorial defence and hierarchical intragroup and intergroup social organization. When behaviours related to these functions fail to mature, there is no development of social organization and no reproduction. As in the case of my study reported above, all members of the population will age and eventually die. The species will die out. For an animal so complex as man, there is no logical reason why a comparable sequence of events should not also lead to species extinction."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1644264/pdf/procrsmed00338-0007.pdf

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What Humans Can Learn From Calhoun's Rodent Utopia

Within the enclosure known as Universe 25, several pairs of mice bred a population, which ultimately swelled to 2,200. Eventually, they established social orders that created inside and outside factions, and soon mating ceased altogether. The study confirmed his grim hypothesis, based on earlier studies of the Norway rat in small settings. In his theory he suggested that overpopulation spawns a breakdown in social functions. That, in turn, inevitably leads to extinction. Though wildly controversial when first made public, Calhoun's theory has raised concern over the years that the social breakdown of Universe 25 could ultimately serve as a metaphor for the trajectory of the human race. Consequently, the “rodent utopia project” has been a subject of interest among architects, city planning councils and government agencies around the world.
https://www.youtube.com/watch?v=ecgnky8D9r0

 


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