Max sleeps by our bed (2nd floor) and Jake sleeps downstairs by the door. That's how the dogs worked things out, not our idea.
Anyway - the other night Max woke me up with a deep-chested, low growl. He was standing at the bedroom door and the hairs on his back were raised. It was of those growls that really mean business.
So - I opened the door and let him out to get whatever (or whoever) it was he was growling at. He went out and looked around a little bit and then just went back in our room and layed down.
Jake barked a little during this time, as well.
We never heard the door open or close, and they both just calmed down on their own.
What do you think was going on? It wasn't something outside, or Max would have been at the window not the door.