Katie the Catsitter is very concerned about the abuse and mistreatment of animals. The cats’ abilities and exaggerated intelligence act as a reminder that animals are thinking, feeling beings who deserve to be treated with care and respect. The cats’ abilities also foreground their working relationship with the Mousetress. When Ms. Lang is eventually caught and arrested, the specific, useful things that they’re able to do make it possible for Katie to rescue her.

While this obviously does not reflect the real world—cats cannot orchestrate a jailbreak—the novel is interested in the ways that animals have helped humanity throughout history. In her speech at the animal rights protest, Ms. Lang points to several examples where animals have improved and saved human lives. In this way, the cats symbolize that working relationship, and by rendering them with their own strengths, skills, and personalities, the novel underscores how animal cruelty is abhorrent and misguided.

The cats also provide the opportunity for Katie to model what a more ideal and healthy relationship with animals could look like. She takes the time to learn their names and individual quirks; she treats them with care and consideration; and eventually she learns that she must earn their respect, rather than the other way around.