Umm, texasmama? You have a Great Pyrenees, right?
Umm, Pyrs bark. A lot. But you are mistaken about the whole "no reason" thing. You see, apparently your homestead was targeted by marauding Huns in the wee hours. Your noble canine's exquisite sense of hearing detected the gathering hordes, and her thundering sounds of warning frightened them off.
Or maybe it was a neighbor's cat. But you know how dangerous cats are, right?
In either case, you and your family survived the night, now didn't you? All because of the brave dog who stayed awake all night defending you and yours. So leave her alone to sleep on the couch all day, okay?