The Burgess Animal Book For Children in "Shadow And His Family"

"The one good thing Shadow the Weasel does is to kill Robber the Rat whenever they meet. Robber, as you know, is big and savage and always ready for a fight when cornered. But all the fight goes out of him when Shadow appears. Perhaps it is because he knows how hopeless it is. When Shadow finds a barn overrun with Rats he will sometimes stay until he has killed or driven out the last one.