Early yesterday morning, Buster was trying to get into our bed, so I kicked him out of the bedroom and went back to sleep. I heard a beeping noise coming from the living or dining room, but didn't think much of it at the time.
A little while later, Brian got up for work and woke me up to say that there was something wrong with Buster. Brian brought him into the bedroom and he was shaking like a leaf. It was not unlike when we have a bad thunderstorm. But the weather was just fine. We then wondered if he got into something that he shouldn't have, but we couldn't figure out what that would have been since our house is pretty much dog-proof at this point.
Buster wouldn't leave the bedroom, but I left it in order to investigate. While I was looking around, I heard the beeping noise again. It was our carbon monoxide detector, which was emitting a low battery warning. You might not know this about Buster, but he doesn't like beeping noises. This goes back to his puppyhood when Brian was trying to figure out the alarm system that we bought for the office and accidentally set it off a couple of times (we couldn't use the microwave for a week after this incident without Buster going nuts).
So, I replaced the battery in the carbon monoxide detector and, while Buster was still on alert, he was more or less ok at this point.
Fast-forward to today. I was working on my computer in the living room this afternoon and thought I heard a beep. I looked over at Buster and found out that he definitely heard a beep. I couldn't tell where it was coming from for a few minutes--it was the smoke detector in our family room. By this point Buster was shaking again and wouldn't move from the carpet by the door. He sat there for about 30 minutes (until the shaking stopped) and then moved to the dog bed.