Be sure to do what MuleMom said about checking everything that's closed! When I was growing up we had a cat that dissapeared. After three days my Mother open a built in drawer in the wall in my brother's bedroom, to put some stuff away. (My brothers were older and not home much by then)...there was the cat; she'd jumped in and because the drawer was on a roller thing, it just rolled shut with her inside! I guess she didn't say much or we couldn't hear her; she didn't even go to the bathroom in there! No harm done, but it was memorable!