Earlier quoted context omitted.
My cat is good at killing birds, chipmunks, bunnies, and mice. I doubt she could deal with a rat - probably too big.
Put a bell on your cat! Outdoor cats are responsible for a huge amount of ecological devastation, the least you can do, if you insist on your predator roaming freely outdoors, is put a bell on it to try and give local species a warning.
Cats as a species kill an emotionally large sum of birds and small mammals, but they don't radically transform ecosystems. It's human industry and habitat expansion that devastates ecologies, not their garden prowlers plucking the occasional bird or chipmunk.
I'd never bell the lad.