Question: If Jonathan and Mr. Ages were the only mice to survive the escape from NIMH, then where did all the other intelligent mice come from? Did one or both of them father a new generation of intelligent mice? Mrs. Brisby's marriage to Jonathan makes this all a little confusing.
Answer: Mrs. Brisby tells Nicodemus that Jonathan had been teaching her to read and her children as well. The children were better at reading that she was but that might be something that they inherited from their father. I think Mr. Ages was also able to read so that makes him intelligent as well. Remember the injections that the mice and rats were given also gave them the ability to read.
Answer: What other intelligent mice? I have watched the movie many times and I don't remember seeing any other intelligent mice. The mice that tried to escape with the rats were sucked down the ventilation shafts, so we don't know what happened to them.
Well, Mrs. Brisby for one, and by extension, her children. She wasn't part of the experiments at NIMH, so why does she possess human intelligence like Jonathan and Mr. Ages? Similarly, why do Jeremy, Auntie Shrew and the Great Owl have human-like intellect as well?
Answer: He doesn't per se, the rats release him when they show up to move Mrs. Brisby's house.
Grumpy Scot