I have a lovely two year old cat which I got from the RSPCA six months ago. She always stayed in at night until last week. Now she disappears and stays out all night - the strange thing is that she does it every second night - Saturday, Monday, Wednesday. She reappears in the morning but is not hungry or tired so I assume somebody is keeping her overnight and feeding her. Can anybody else thing of another explanation? This one has me stumped!