Since we are now including RATS as animals

, then allow me to take this opportunity to suggest a serious literary novel that I HIGHLY, HIGHLY recommend:
Firmin the Rat, by Sam Savage
https://www.goodreads.com/book/show/349164.Firmin
This is a sad, funny book that is also a commentary on isolation and what it means to be a rat in a cruel world. There are some existential moments, buy hey!, don't we all have moments when we reflect upon our place in the world? Read this book, and you'll begin to understand what separates readers from non-readers.
Kobo [UK]:
https://www.kobo.com/gb/en/ebook/firmin-1