That was the way it was for one of the kitties when we brought the dog into the picture. I'm not sure if a cat brain actually works this way, but it seemed that at some point one of the cats realized the dog was not a temporary visitor. We had had plenty of other temporary visitors of human and dog variety, but they'd stay for maybe a weekend at most, and the one who took issue with such visitors would do a combo of either being okay about it or hiding until the visitors moved on. With the dog, after about two weeks, she appeared to return to normal behavior but would leave a neat pile of cat shit beside her food dish. It was like the cat equivalent of a passive aggressive note: "dear humans: fuck you." Over time and much coddling she stopped doing this, but now if anyone makes a fuss - human or animal - she comes charging into the room and bats the dog in the face a couple times. Any strife, in her kitty mind, is the dog's fault, and it is her job to put him in his place. She weighs maybe 4lbs, the dog weighs 34lbs. Needless to say, she is a very lucky kitty that we have trained the dog so throughly.