The Shrew was born a mundane shrew on the Fitzgibbon Farm at some point before 1982. When the first Uplifted Rats, freshly escaped from NIMH, found their way to the Farm, they psychic waves progressively heightened her mental abilities, granting her limited sentience. The Shrew would remain oblivious to this for years, and actually loathed the Rats of NIMH, whom she saw as dangerous hooligans.
Handling the FieldEdit
Due to her no-nonsense, practical mind, and the fact that she was more Uplifted than most other animals on the Farm, the Shrew came to handle most of the field animals' daily lives, notably Moving Day. She was especially close to Mrs Brisby, whom she grudgingly recognize was one of the cleverest creatures around, to the point that Mrs Brisby's children called her Auntie Shrew, a name she kept all her life.
The Secret of NIMHEdit
The Shrew was only a witness, and not an acute one at that, to the events of 1982 which led to the Rats of NIMH leaving the Rosebush Colony for Thorn Valley. She was the one to advise Mrs Brisby to go and see the Great Owl, but was not told of the Owl's advice to go to the Rats of NIMH, presumably because Brisby felt she would oppose it on principle due to her hatred of the Rats. She was also a minor obstacle for Jeremy the crow, whom she confused for an attacker after Mrs Brisby had sent him to her house to watch over her children.
After Mrs Brisby's encounter with the Rats of NIMH, Auntie Shrew turned herself around completely, and came to admire the rats, and especially the deceased Nicodemus, treating his sayings and his Prophecy with an almost religious deference.
Differences with the NovelEdit
In the novel, the Shrew (never called Auntie Shrew) is a relatively minor character. Her role as a thick-headed traditionalist who despises the Rats is identical to the movie, but she never babysits Mrs Brisby's children, and never interacts with Jeremy.