Oh my gosh they are awful! I've had plenty of lose rats and they generally stay really close to the racks, maybe venture into the next room in the basement. The ASFs, they were all over my danged house! I had some upstairs in my kitchen drawer chewing up all my spoons/spatulas. I don't even know how they managed to get up and in the drawer! I was beyond pissed to say the least and they were super hard to catch!