my rats still dont like running around in the house very much and I've had them since October. Usually I put them on the couch with me and let them play under blankets and stuff (and now have a hole chewed in my couch - gotta watch) but one time I let them on the floor while I was cleaning and thought maybe if I left them long enough they would get comfortable and start exploring. Well I left them for about an hour, in the living room and when I went to put them away they were like wild rats. Couldn't catch them, one even was acting like she wanted to bite me. So if I let them run on the floor it's a max of 30 minutes and they still dont wander very far, they usually go under the couch and stay there. They're very calm when I'm holding them, they don't mind being held but I can leave the cage open all night long and they never try to leave. I wonder if mine are just weirdos.