I have two cats, sister and brother. They were 2 years old in July. The big Black one, male, Bozz, has recently began bitting our carpet and pulling threads of carpet out. The little female, Miller, does not do this. They live in our 1,000 sq. foot garage, which is heated and has windows and cat sills they can sit on. When we are home of the evening, we bring them in for several hours, but they always let me know when they want to go back out. I'm wondering though if Bozz, is mad about this situation, even though he lets me know he wants back out. I squirt him with the water bottle when he does this, say NO, and put him out. Then when he comes back in, after a while, maybe an hour or so, he starts again. Why has he begun this? How long will it take for me to get my poin across to him that he CANNOT continue to bit my carpet?