The story behind the rats of NIMH

By | December 14, 2022

In 1982, there was a “not-from-Disney” animation that had fascinated me… “The Secret of NIMH.” Just discovering it root is bringing back memories. (Official Trailer.)

Ms Frisby, escaped from NIMH

In the 1971 book Ms. Frisby and the Rats of NIMH, written by Robert C. O’Brien, the rodents strive to create their own utopia after escaping from a research facility. Amazingly this was inspired by an experiment run by John Bumpass Calhoun at the National Institute of Health (NIH) in Bethesda, Maryland, started in 1968. More precisely at the National Institute of Mental Health (NIMH; see e.g.: 12 Facts About The Secret of NIMH.) The Mouse Utopia ended in 1973.

The article cited below describes the details on how the experiments came to be, from the boyhood passions of J.B. Calhoun:

The Doomed Mouse Utopia That Inspired the ‘Rats of NIMH’

The rats that became smart at NIMH

The first 8 white mice installed July 9, 1968, multiplied to 620 by August next year, 1969. The article describes the end of the Utopia in dire terms:

Such rapid growth put too much pressure on the mouse way of life. As new generations reached adulthood, many couldn’t find mates, or places in the social order—the mouse equivalent of a spouse and a job. Spinster females retreated to high-up nesting boxes, where they lived alone, far from the family neighborhoods. Washed-up males gathered in the center of the Universe, near the food, where they fretted, languished, and attacked each other. Meanwhile, overextended mouse moms and dads began moving nests constantly to avoid their unsavory neighbors. They also took their stress out on their babies, kicking them out of the nest too early, or even losing them during moves.

Population growth slowed way down again. Most of the adolescent mice retreated even further from societal expectations, spending all their time eating, drinking, sleeping and grooming, and refusing to fight or to even attempt to mate. (These individuals were forever changed—when Calhoun’s colleague attempted to transplant some of them to more normal situations, they didn’t remember how to do anything.) In May of 1970, just under 2 years into the study, the last baby was born, and the population entered a swan dive of perpetual senescence. It’s unclear exactly when the last resident of Universe 25 perished, but it was probably sometime in 1973.

Paradise couldn’t even last half a decade.

And so it goes… Are there lessons humans should learn?

A 38min YouTube video describes the experiment:

John B. Calhoun Film 7.1 [edited], (NIMH, 1970-1972)

A renewed interest in this story, in the May 2022 issue of TheScientist: Universe 25, 1968–1973 and today (Jan 10, 2023) on LinkedIn by Alvin Foo 32,944 “likes” and 3,181 comments, but seems to be highly biased: “The Universe 25” (seems to be readable without being subscribed.)

Credits: Images generated by AI at Stable Diffusion 2.1 Demo.

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