Mrs. Frisby and the Rats of NIMH

Nicodemus is the leader of the highly intelligent colony of the Rats of NIMH. Like his closest ally Justin, Nicodemus’s name is biblical in origin and means “Victory of the people.” Nicodemus’s character fits this description, as he is an archetypal just leader who does everything in his power to bring his colony to freedom, happiness, and independence, thus leading them to victory. Nicodemus is a kind rat who speaks “graciously, with an air of quiet dignity” (76-77). He has a scar over his left eye, the result of an attack by Dragon, and carries a satchel over his shoulder. When Nicodemus meets Mrs. Frisby and hears her name, he is willing to do whatever is necessary to help her move before plowing day. Nicodemus is forever grateful to Jonathan Frisby, without whom he and the others would likely never have been able to escape NIMH.

It is Nicodemus who tells Mrs. Frisby everything about the rats, the experiments, and how they came to live inside the rosebush. He speaks of his experiences with a calm disposition, never becoming angry or emotional. He tells Mrs. Frisby about life in the laboratory and afterward as objectively as possible, admitting his faults and mistakes, and describing the rats’ current dilemma. Nicodemus is the first one to speak up when the rats become complacent and lazy with their lavish lifestyle. He is tired of stealing and being part of the Rat Race and wants to live a more moral existence free of theft and dependency on humans. Nicodemus believes that “a thief’s life is always based on somebody else’s work” (168) and feels that since the rats are now intelligent enough to make their own way, there is no longer any need for them to live the way common rats do.

Nicodemus is a loyal friend and meticulous planner. He remains true to the Rats of NIMH, guiding them to a better life, and forms close bonds with Justin, Mr. Ages, Jonathan Frisby, and later, Mrs. Frisby. Nicodemus is wise and willing to teach others what he knows, and he regularly holds meetings to voice his thoughts and hear the opinions of the other rats. This makes him a just leader who does what is right for the entire colony. The Plan Nicodemus devises with the other rats allows them to build a stock of seeds, build their own plows, clear a spot of land in the valley beyond the mountain, and eventually move there to live out of sight of all humans. Nicodemus knows that the rats are “twenty […] alone in a strange world” (128) and builds a strong sense of comradery between them as a result. Nicodemus is one of the rats who stays behind to fool the humans, and Mrs. Frisby is too high up to specifically see which rats make it out and which do not. Therefore, it is not known whether Nicodemus makes it out of the rosebush alive in the end.

Justin is one of the major characters and the bravest rat in the colony. He exemplifies courage many times throughout the story and does so with humility and humor. The name “Justin” is a biblical name meaning “righteousness,” and Justin the rat exhibits this trait through his courage and loyalty to the rat colony. He is also fair and understanding; he is the first rat to give Mrs. Frisby a chance and allow her into the rosebush home.

Justin’s bravery is significant in several stages of the rats’ advancement toward freedom and in saving Mrs. Frisby’s home. He is captured along with Nicodemus and the others and taken to the NIMH laboratory for experimentation. He becomes part of the group that becomes super intelligent, and while all of the rats become this way, Justin seems to be even smarter than the others. He is the one who figures out how to open the cages and the one who is brave enough to try it. He escapes the cage one night to look around and invites Nicodemus out to do the same. This is the moment the two become friends, and their bond is sealed from then on. Justin pushes the boundaries more and more, escaping during daylight hours when the scientists are present to see how they react. He climbs around, examining the window and the air ducts, thereby finding their means of escape. Justin becomes known to the scientists as the rat that escapes, and because it is only him who is ever found, they suspect nothing. Justin, Jenner, and Nicodemus plan to leave the lab through the air ducts and escape the lab forever.

Justin is also instrumental in introducing Mrs. Frisby to the rat civilization and helping her save her family. He takes her on a tour through their underground tunnel system and explains their plan to leave the farm. Justin also ushers Mr. Ages to and from his home to fetch medicine after Mr. Ages breaks his leg; Justin is not too proud for any task. He is willing to do whatever is needed to help the colony and the Plan unfold successfully. When Mrs. Frisby is captured by the farm boy and kept in a bird cage, Justin comes to save her and take her home, teasing her and keeping a stressful situation light. Although it is not known for sure whether Justin survives the gassing, it is implied that he was likely one of two rats who got caught in the storage room and never made it out. Brutus describes a rat who “kept pulling [him], and then pushing […] He gave [Brutus] one last shove toward [the exit], and then he turned back” (224). This level of bravery and self-sacrifice is in line with Justin’s character and previous actions, and upon hearing the whole story, Teresa guesses that it “must have been Justin” (230) who stayed behind to help.

Mr. Ages is the medicine mouse who lives on the other side of the farm. He has white fur that is “so glossy he [seemed] to almost glow” (14), and nobody is sure if he is old or if he has just always been white. He was part of the NIMH experiments, giving him super intelligence and extremely long life. He and Jonathan are the only two mice who escape from NIMH, and they become dear friends as a result. Each participant in the experiment had a different personality and passion they used their newfound intelligence to master, and for Mr. Ages this passion is medicine. He creates “the draughts and powders that could sometimes save the sick from dying” (12), using various herbs, seeds, roots, flowers, and mushrooms. Mr. Ages can also make sleeping powder, which is regularly used to keep Dragon the cat docile while the rats perform their work.

Mr. Ages saves Timothy from dying when he is young and sick and again when Timothy gets pneumonia. He creates a powder that allows Timothy to heal in three days but warns Mrs. Frisby that Timothy must rest for another 30. Mr. Ages also helps Mrs. Frisby gain entrance to the rat colony when she encounters him in the rats’ tunnel. Later, Mr. Ages supplies the sleeping powder that Mrs. Frisby puts in Dragon’s food so the rats can move her home safely. Mr. Ages performed the same act just a few days before, causing him to break his leg. Despite his injury, he does whatever he can to help his rat friends escape the farm alive. Mr. Ages also verbalizes the final lines of the novel, remembering the rat who stayed behind to help the others as the gas flooded in: “Whoever he was, he was brave” (224).

Jenner is Nicodemus’s best friend and foil. They are somewhat opposite in character, and Jenner’s disagreements with Nicodemus’s moral principles later on eventually lead to Jenner and six other rats abandoning the group to make their own way. Jenner has known Nicodemus since before the experiment when they were just regular rats living in a marketplace. The two of them regularly led their colony to find feasts after dark. One such excursion ended in disaster when Jenner, Nicodemus, and several other rats are captured and taken to a lab to be experimented on.

Jenner expresses his disdain for their previous life of eating garbage and living on the streets while the rats are still in the lab. The plan had been set for them to escape, but Jenner is worried about what life outside the lab will be like now that the rats are highly intelligent. He asks Nicodemus, “Where does a group of civilized rats fit in?” (134), making the point that they are no longer like other rats but also not like any other creatures either. Jenner foresees a lonely and difficult life for the rats. Jenner also foreshadows his death and the rosebush gassing when he asks Nicodemus, “What will happen when [Dr. Schultz] announces that there’s a group of civilized rats roaming around—rats that can read, and think, and figure things out?” (134). Jenner believes the rats have become smarter than the humans who made them. In the present, it is suggested that Jenner is found dead with the group of rats who followed him out of the rosebush, though it isn’t clear whether all seven of Jenner’s group was killed or if there were only six. Those rats were attempting to steal a motor and were electrocuted. Finding them dead in such a way caused speculation that these were the escaped rats, which led to NIMH becoming involved and eventually to the destruction of the rosebush and the death of two other rats.

Jonathan Frisby is Mrs. Frisby’s husband, the father of her four children, and her emotional anchor both before and after his death. He “died only the preceding summer” (2) before the story begins when he was attacked by Dragon while attempting to dose him with sleeping powder. Jonathan Frisby was a dear friend of the rats and spent much of his time helping them. He never told Mrs. Frisby about his past, the experiments, or his relationship with the rats because he did not want to worry her. However, her not knowing in many ways left her powerless to change her situation and get over his death. In fact, she does not even know how Jonathan died until she finds out from the rats.

Memories of Jonathan teaching the children how to write and being thoughtful and anxious like Timothy flood the early pages of the novel. Mrs. Frisby is clearly still drowning in grief and does not know how to move forward, which is largely due to her lack of knowledge surrounding Jonathan’s life and death. She eventually learns that Jonathan was part of a side experiment at the NIMH lab, one that also made him and several other mice super intelligent and long-living. Jonathan could not bear the thought of Mrs. Frisby aging without him, which was another reason he refrained from telling her about his past. Evidence that Jonathan was part of the experiment comes clear early on, as Mrs. Frisby recalls how easy it was for her children to learn how to read and reasons that it must have been due to her age that she does not read as well. Jonathan is instrumental in his, Mr. Ages, and the rats’ escape from NIMH, as he and Mr. Ages are small enough to climb through the gap in the wire air duct cover and unbolt it from the other side. Without them, the rats may never have escaped alive. The memory of Jonathan is also key in Mrs. Frisby’s success in dealing with the rats and the owl. All of them know his name and remember him as a hero and friend, so they are willing to help his widow as a result.

Timothy Frisby is the youngest son in the Frisby family and the most like his father Jonathan. He is “narrow of face; his eyes [are] unusually large and bright, and shone with the intensity of his thought when he spoke. He was, Mrs. Frisby knew, the smartest and most thoughtful of her children” (8). He is prone to worry due to his intelligence, which seems to make him more likely to fall ill. When Timothy was still an infant, he became mysteriously sick. Mrs. Frisby and her husband sought the help of Mr. Ages to cure him, which he did; however:

this had been the beginning of his frailness. From that time on he tended to stumble a little when he walked, especially when he was tired; he never grew as vigorous as his brother, Martin. But he thought a deal more, and in that he resembled his father. (13)

When Timothy becomes sick again with pneumonia as spring falls on the farm, panic ensues as Mrs. Frisby desperately tries to find a way to move him without him dying of cold. Mr. Ages warns that he should not be moved for at least 30 days, and it is this very dilemma that leads Mrs. Frisby on the greatest journey of her life in the name of motherly devotion. It also sparks the beginning of the uncovering of many family and farm secrets, such as the NIMH experiment and Jonathan being part of it. In the end, Timothy is able to survive the short move to the other side of the rock, and the family moves to their summer home by the brook in the summer. Timothy is fully healed, and Mrs. Frisby finally feels at peace.

The owl, old and intimidating, is the observer and knowledge keeper of the forest. He flies over everything, seeing what he can and spending his days in the hollow of his tree pondering the world. When Mrs. Frisby first arrives to talk to the owl, she is afraid of possibly being eaten but soon finds him to be at least somewhat reasonable. At first, the owl lacks any desire to talk to Mrs. Frisby, not knowing her name or why she is there. To Mrs. Frisby, a small mouse, “the owl looked very large. Each of his feathery feet was tipped with five gleaming talons an inch long. His beak was curved and sharp and cruel” (49). The owl is old and has seen many creatures come and go, and he seems to have little patience left for pettiness. All of the other birds and many other animals in the forest revere and respect the owl, including Nicodemus and Mr. Ages.

When the owl hears that Mrs. Frisby is the wife of Jonathan Frisby, he is willing to spare a few minutes of his time to talk to her about Timothy’s sickness and the farmer’s plan to plow in a few days. Knowing she is Jonathan’s wife, the owl is confident that the rats will be willing to help Mrs. Frisby with her dilemma. The owl tells her, “You must go to the rats […] I think they will help you, and if they will, they can” (53). He warns Mrs. Frisby to be secretive about anything she sees or hears there but does not tell her why. The owl tells her to ask for Nicodemus and Justin to help move her home to the “lee of the stone” (54). He effectively foreshadows the rats’ intelligence and their connection with Jonathan in this moment, but Mrs. Frisby remains in the dark. 

Jeremy is the crow who lives around the farm. Mrs. Frisby finds him tangled up in some string one morning on her way back from seeing Mr. Ages for some medicine. Jeremy is not the brightest of creatures, as he got himself in this mess by being attracted to a shiny piece of string; however, he is a loyal friend. When Dragon the farm cat starts to approach Jeremy, Mrs. Frisby quickly gnaws the string away and frees him. He promises to return the favor whenever she asks: “If the time ever comes when I can help you, I hope you will ask me” (24).

Sure enough, Mrs. Frisby enlists Jeremy’s help a few days later. Luck plays a major role in the success and survival of the creatures in the story, and Mrs. Frisby’s original encounter with Jeremy is no exception. It is Jeremy who knows where the wise owl lives and who offers to take Mrs. Frisby there and back. This saves her time as well as the risk of running through the forest alone and vulnerable to predators. Jeremy also waits for Mrs. Frisby while she speaks with the owl, even though it takes until dark. Finally, Jeremy hints at the rats’ great Plan to leave the Fitzgibbon farm and start their own life in Thorn Valley. Although Jeremy is a static character, he proves himself instrumental in helping Mrs. Frisby and her family survive.

Brutus is a young rat who guards the entrance to their underground home inside the rosebush. He is one of Nicodemus’s closest friends and the first rat Mrs. Frisby meets. Brutus is so big that “he would almost be a match for Dragon” (65), and Mrs. Frisby is immediately intimidated by him. He is dutiful and loyal to his rat colony and doubtful of Mrs. Frisby until Mr. Ages talks with him. At the novel’s conclusion, Brutus is one of the 10 rats who stay to deceive the farmer and scientists to help the others escape and the last rat to make it out alive. He is willing to die to save his friends, and almost does, except a rat he did not see pushed him all the way out of the tunnel just in time. He crawls out of the hole and falls unconscious until Mr. Ages gives him a tonic. Brutus survives and makes his way to Thorn Valley with the other rats.