Strange digging noises

I tried to post this a day or so ago but it wouldn't publish. I have no idea why not. So I'm trying again. Night before last we retired to bed about 10:30. Things have changed a little here as my wife has had a major problem with her leg. Because she has to wear a wound vac for a few weeks and she's afraid the dogs will get tangled in the hoses on it; she has moved into our guest room (known as the Noah room). The dogs and I remain in the master bedroom. We don't have airconditioning but do have a large ceiling fan over the foot of the bed and I suspect thats why both of our schnauzers are suddenly interested in sleeping at the foot of the bed, although the younger of the two will often move more toward the headboard before morning. Last night we had all settled in for a good nights sleep. I was pretty much sound asleep when all of a sudden I hear this frantic digging noise. Any of you who have dogs will know what I mean. Generally its said that they are making themselves a bed. They dig frantically for a while then turn around three times and flop down and go to sleep. Last night the digging just kept going, finally I yelled "Rowdy stop that". When I looked toward the foot of the bed Rowdy was curled up and looking at me bleary eyed. Well I suppose he was bleary eyed, I couldn't see him that clearly in darkened room. But the digging was still evident and he was only reacting to my voice. He wasn't digging anything. The other dog was up almost even with my head in the bed and she was asleep, or at least looked like she was. I can tell you I turned on the light at the side of the bed in a hurry. As soon as the light came on the digging stopped. It had sounded like it was coming from the area of the heat register where the older dog normally sleeps. There was nothing there. There was nothing in the bedroom but us three. Yet what ever was digging had to be as big or bigger than my dogs. Yet my dogs ignored the episode completely. Finally, just figuring this old house was at it again I turned off the light and went back to sleep. Another mystery of thos old house.