Strange Noise

    Last night, probably about 3 or 4am I had to go to the bathroom. I didn't turn on any lights as the window light was ample to navigate the bedroom and we have a small night-lite in the hall (one of those 2X3 inch green squares). After reaching the bathroom I heard what I thought was my dog shakening heck out of one of his toys. Any of you who have or have had a dog, understands what I mean. Its a very characteristic sound. I said, "What are you doing in here?" I got no response and he didn't come running to me as he normally would. I couldn't see him but the sound eminated from a part of the bath that has an eastern window. I figured he'd follow me back down the hall to the bedroom. I heard nothing more; but when I reentered the bedroom I could see my dog curled up in his bed obviously sound asleep. He certainly didn't pass me in our narrow hall. So what did I hear?