With overlapping times my wife, son, and I had a female border collie for 19 years and a female rottweiler that made 15 (Susan and Sandy) but never have we ever seen more alert animals that were "ready for attack" VS an intruder than cats.
Here we see the momcat Mister Mittens on the living room sofa tonight. Her belly is full but instead of curling up into a ball she has all 4 legs extended (somewhat) and ready to snap out claws in case of some nutjob crashing into our home.
As backup, Sweet Babycakes is in my wife's bedroom and ready to go.
Yeah, maybe you just have to love cats and dogs and other strange creatures.