My dog is sleeping in odd places.

Question
I'm not entirely sure if this would qualify as a behavior problem, but it's definitely a change in my dog's behavior.  

My dog is 11 years.  His name is Jack.  He used to sleep on the couch, or in my room on the floor, but for the last three days, he's been sleeping on the bottom shelf of a book case that I use in the bathroom to put sheets and towels on.  He's pulled all the sheets off onto the floor and is sleeping on the bare wood.  

I'm worried.  I don't know why, but when I first discovered he was doing this, I got scared that he might be dying or something, I don't know.  What do you think might be going on with him?  Any advice would be greatly appreciated.

Answer
I don't blame you, and I commend you, for worrying about this behavior.  I would, also.  It might be that Jack has discovered a new and interesting cubby for himself; it might be that Jack is responding to some stimulus (aural, visual, etc.) with this behavior; he could be suffering from a cognitive dysfunction due to age or the result of a neurological event.  I think your best course of action is to have Jack evaluated by a veterinarian immediately; full blood chemistry, neurological evaluation, abdominal palpation, etc., the works.  Meanwhile, observe Jack closely for other signs.  Is he urinating normally, defecating normally, eating well, drinking normally, responding normally in every other way all day and all night?  These are things your veterinarian should want to know.  Even normal test results don't guaranty anything, unfortunately, but it's best to make the first appointment you can with your vet.  Please repost with results, both of his examination and your observations of Jack's overall behavior.