Sounds on rear stairwell

Last night I was upstairs, my wife needed the daily paper and I had taken it upstairs to read. I was bringing it back downstairs by our rear stairs. The rear stairs goes up off the kitchen hall. They are not well lit, narrow, and rather gloomy. As I started down I heard what sounded like a dog padding down behind me. The sound went around me on down the stairs and through a shut gate. There was no dog there. My dogs were asleep in the diningroom. Things like this leave you scratching your head.