Column Science Fiction Film Club The Secret of NIMH: The Unlikely Film That Revived American Animation How Don Bluth turned a beloved children’s book into a lovely, heartfelt classic. By Kali Wallace | Published on October 22, 2025 Credit: MGM / United Artists Comment 0 Share New Share Credit: MGM / United Artists The Secret of NIMH (1982). Directed by Don Bluth. Written by Don Bluth, John Pomeroy, Gary Goldman, and Will Finn, based on the novel Mrs. Frisby and the Rats of NIMH by Robert C. O’Brien. Starring Elizabeth Hartman, Dom DeLuise, and Derek Jacobi. In the February 1962 issue of Scientific American, zoologist John B. Calhoun published an article titled “Population Density and Social Pathology,” in which he details his experiments using rats to study changes in social behavior in response to overpopulation. Calhoun had spent several years conducting the experiments at the National Institute of Mental Health (NIMH) in Bethesda, Maryland. He built what he called “rat utopias” (which don’t look like utopias at all), or enclosed spaces in which populations of brown rats were provided access to unlimited food and water and allowed unrestricted population growth. Calhoun, working with his many pens of rats, was interested in separating the effects of population growth from the pressures of resource scarcity. He coined the term “behavioral sink” to describe what he found, which was that even if they didn’t have to fight over food, the rats still developed “behavior disturbances” such as a drop in fertility, high infant mortality, cannibalism, and behavior that ranged from “frenetic overactivity” to “pathological withdrawal from which individuals would emerge to eat, drink and move about only when other members of the community were asleep.” Oh, and “sexual deviation,” of course. His overall conclusion was that high population density led to a range of aberrant behavior even with an abundance of resources—in rats, yes, but Calhoun was also very clear that he was conducting these studies because he was interested in extrapolating the results to human societies, and specifically to the presumed moral decay that comes along with the urbanization of human societies. Now, at this moment you are probably thinking, “Why are we talking about rat sex in an article about a children’s movie?” Let’s cast ourselves back in time to the 1960s, just for a moment. There was a lot going around the world, and right alongside all the wars and revolutions and movements, overpopulation was a growing source of concern. When Paul R. Ehrlich (and his uncredited coauthor and wife Anne Ehrlich) published The Population Bomb in 1968, it was a runaway bestseller, largely thanks to its dire predictions about the many terrible catastrophes that would inevitably happen as the human population exploded. Most of which, it must be noted, have not come to pass, and certainly did not come to pass on the very rapid timeline that Ehrlich predicted. If you’re a fan of classic sci fi, you know that fiction writers were also exploring those ideas in the ’60s and ’70s. Harry Harrison published Make Room! Make Room! in 1966 (which would go on to become the movie Soylent Green in 1973), William F. Nolan and George Clayton Johnson published Logan’s Run in 1967 (the film would arrive in 1976), and the next year John Brunner published Stand on Zanzibar—all classics of overpopulation sci fi, and I’m sure there are more that I’m forgetting. Among the writers paying attention at the time was a National Geographic journalist by the name of Robert Conly, who in his spare time wrote fiction under the pen name Robert C. O’Brien. He published his first novel, The Silver Crown, in 1968; it’s a sci fi children’s story about a mind-control machine, and it didn’t make much impression at the time. But O’Brien’s second book was different. O’Brien had read about Calhoun’s rat studies; it’s possible he even visited Calhoun’s lab. But instead of extrapolating the studies to human populations, O’Brien kept the rats and gave them human-like intelligence. The possibility of scientifically increasing intelligence was another favorite sci fi topic at the time, most famously in Daniel Keyes’ Flowers for Algernon, first published as a short story in 1959, then as a novel in 1966. (I have no idea if O’Brien was aware of Keyes’ story. O’Brien died in 1973, so there isn’t much out there about his literary works in his own words. His fourth and final book, the 1974 post-apocalyptic novel Z for Zachariah, was published after his death.) O’Brien took his ideas about rats and how they live, and he wrote beloved children’s classic Mrs. Frisby and the Rats of NIMH, which was published in 1972. It’s a beloved classic both in the usual sense, as it won the Newbery Medal and immediately became a classroom reading staple, and in the personal sense, because it is deeply beloved by me. It was one of my absolute favorite books when I was a kid. I read it cover to cover dozens of times. I didn’t really pick up on any of the ideas about industrialization and self-sufficiency in communities; I just thought it was cool that the rats were so smart. I had absolutely no idea what NIMH was, and only after I was well into adulthood did I consider that perhaps Mrs. Frisby and the Rats of the National Institute of Mental Health was a rather odd title for a children’s book. It was one of my favorite books, and it also my first experience with being a smug “the book was better” kind of fan, or at least as smug as an elementary school student can be when scorning her classmates for preferring an animated film. My objection to the film wasn’t just that it scared me—which it did, as it has some delightfully spooky parts—but that I didn’t understand why they added magic. Or why they changed “Mrs. Frisby” to “Mrs. Brisby,” because I was a child and did not understand the legal liability of potential trademark infringement. My opinion on the film has softened since I was nine years old. I understand now why they added magic. (And why they changed the name.) I still think the book is better, but the movie is a lovely example of traditional, hand-drawn animation that came along right when the American film industry was flailing around trying to figure out what to do about kids’ movies. I wrote a bit last week, in my piece about Escape to Witch Mountain (1975), about how during the ’70s Disney was shifting away from animated films for children and toward live action films for older audiences. That attempted pivot led to significant conflict behind the scenes, especially among the animators who felt like the studio didn’t much care for their work anymore. That included the higher-ups, such as Disney producer and future CEO Ron W. Miller, dismissing the animators’ attempts to develop their artistry and filmmaking skills and maintain what they believed ought to be the standard for animation quality. A group of Disney animators, including Don Bluth, Gary Goldman, and John Pomeroy, got together and started working on their own film anyway. Working in Bluth’s garage, they put together the short film Banjo the Woodpile Cat (1979). They brought it to Disney as a example of what they could do, but the studio wasn’t interested. So in September of 1979, they left Disney to form their own company. Eleven animators in all quit at the same time—which doesn’t sound like much these days, when film credits contain hundreds or thousands of names, but that was a significant percentage of Disney’s animation department. (As best I can tell, there were perhaps fewer than a hundred people in the animation department at the time, but the precise numbers vary in different sources.) Banjo the Woodpile Cat was the first film from the newly-formed Don Bluth Productions; it would end up airing on television in the next couple of years. Their next project would be their first feature film, and that was an adaption of Mrs. Frisby and the Rats of NIMH, a book that Disney had previously passed on adapting. They went in with a very specific and very public goal: to make an animated film in the classic Disney style, because Disney wasn’t making movies like that anymore. Disney was still making animated films—for example, The Fox and the Hound (1981), which was in production at the time and delayed by the animator exodus—but the feeling both within Disney and among movie critics was that they were mostly retreading old ground both thematically and artistically. The animators who joined Don Bluth in his garage (they did get proper offices eventually) wanted to prove that animated films could still be beautiful, heartfelt, and magical. So they made some changes to the story when they adapted it, as a sci fi story about hyper-intelligent rats discovering literacy and self-sufficiency was not quite what they found appealing about the book. O’Brien’s novel is more focused on the rats themselves, whereas the movie shifts the focus entirely to the mouse protagonist, called Mrs. Brisby in the movie (voiced by Elizabeth Hartman in her final role). They also added the magical elements that annoyed me so much as a child, such as the glowing amulet and the implication that Nicodemus (voiced by Derek Jacobi) is some sort of wizard. They added a rat antagonist in the form of Jenner (voiced by Paul Shenar), who is mentioned in the book but never appears on page, and gave the crow Jeremy (Dom DeLuise) a greater role as very Disney-typical comic relief. The film never really details what happens to the rats, whereas the book is quite clear about how they avoid the humans looking for them (exterminators in the book, scientists in the film) and finally leave to start their self-sufficient rat colony somewhere in the wilderness. Again, I still think the book is better, but knowing the motivations for making the movie and exactly what the people behind it were trying to prove, I understand why they changed what they did. The magic, the humor, the simplified plot about a mother’s courage saving her children—all of that is intended to inspire a particular emotional attachment in the audience, one that Bluth and others felt had become less important in Disney films. It also serves as the showcase for the art, because the animators who’d left Disney along with Bluth did so in part to prove that there was still plenty of room for artistry and craftsmanship in the increasingly technical animation industry. In that, I think, they succeeded marvelously, because The Secret of NIMH is a stunning work of animation. It’s beautiful, vibrant, and surprisingly complex. Basically, the entire movie takes place in settings with ridiculously complicated lighting situations: in the shade of crops and trees in both full daylight and at night, in the spooky darkness of the Great Owl’s (John Carradine) lair, in the artificially and magically illuminated rats’ den, at night during a thunderstorm, and so on. Each of these settings required the artists come up with suitable color palettes for each character, even a character like Mrs. Brisby, who has plain brown fur and no clothes except for a red cloak. They also built and filmed models of certain elements—such as the bird cage from which Mrs. Brisby escapes in the farmer’s kitchen—to achieve a sharp, moving setting into which the animated character could be added. The abundant shadows and constantly shifting light also make great use of all that gorgeous backlight animation, which I talked about briefly back when I wrote about Tron (1982). In backlight animation, the glowing effect is achieved by filming the scene normally with the glowing area blacked out, then filming it again with everything except the glowing area blacked out, and lights and filters placed where the glow is needed. In The Secret of NIMH, backlight animation is used to add contrast and warmth to all those darker scenes and complex shadows. In spite of how much of the film takes place at night or underground, it’s not a visually dark movie at all. (Even if I did find the Great Owl’s lair to be terrifying when I was a child. In my defense, it’s supposed to be scary! That is the purpose of the scene!) The Secret of NIMH was not a huge financial success. For one thing, it was yet another film released during the absolutely jam-packed American movie summer of 1982. (It’s the fifth Summer of ‘82 movie we’ve watched for this film club, and it probably won’t be the last.) But it did make people pay attention to what Bluth and his fellow animators were doing. It’s clear from contemporary reviews that everybody knew they were trying to capture the Disney magic that Disney wasn’t using; that’s directly referenced in many mainstream reviews. Opinions were mixed on just how well the film succeeded in doing that, but people did notice. According to Gary Goldman, several Disney animators attended the film’s premiere. The industry and the critics were watching to see what Bluth Productions would do next. What they did next was, alas, go bankrupt, then come back to life with the help of Steven Spielberg’s Amblin Entertainment, with whom they would make An American Tail (1986)—which was a massive success—and The Land Before Time (1988). Then, with the help of the British studio Goldcrest, they would make All Dogs Go to Heaven for release in 1989, which was not at all coincidentally also exactly when Disney’s animation department finally got its shit back together. Disney threw a massive amount of time, talent, and money at The Little Mermaid (1989), and it’s not mere Hollywood rumor or speculation to say they did that precisely because Bluth, Goldman, and the others had proved that they could do Disney’s thing better than Disney had been doing it for some time. In a 2022 interview with the Los Angeles Times, Bluth said that Roy E. Disney tried to draw him and the others back to work for Disney again. When Bluth declined, Roy Disney apparently said, “You can’t win this, Don. We’ll crush you.” Don Bluth, for his part, always comes across as pretty philosophical about how Disney reacted to its own animators becoming competition. I don’t get the sense that he or any of the others were surprised when Disney realized that people still wanted beautiful animated films with strong stories. Disney was always the giant of the animation industry—but in the ’80s, it was a giant that might have kept on slumbering for a while longer if Bluth and the others hadn’t quit their jobs to make a lovely little movie about a mouse who needs a bit of help from some friends. What do you think of The Secret of NIMH? Any other lifelong fans of the book out there?[end-mark] Next week: I’m not joking when I say I remember absolutely nothing about The Last Starfighter except that I’ve seen it and it involves a video game. Watch it on Apple, Amazon, Fandango. 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