Around one 'o clock in the morning, when Ben and I have retired to bed, and he is draped across my torso, having twitchy-pawed cat dreams, this something starts moving directly overhead. And I mean directly. It sounds like something with claws is climbing down the wall six inches from my head.
When this happens, Ben jerks awake (much to the detriment of any patch of flesh under his paws) and stares upward at the ceiling, while the scuffling, scurrying, occasionally thumping noise goes on overhead.
I can think of three possible suspects. Squirrels definitely hang out on the roof here--it's not a surprise that they might build a dray inside the building, or whatever. On the other hand, squirrels are largely diurnal, and this critter does a definite tapdance in the small hours of the night. Woken up and scuffling around? Maybe. There was a heavy rainstorm last night, and the creature in the crawlspace was moving quite a bit, so it's possible that they're just light sleepers.
Rats, in any large human habitation, are pretty likely. (You know you're old when you go to Disneyland and find yourself wonder how they're controlling the rat population so efficiently behind the scenes.) Thing is, I haven't seen any little ratty calling cards scattered anywhere inside, and whatever it is sounds...heavy. I mean, an adult male rat can get pretty hefty, certainly, but while I could just about accept a klutzy squirrel thunking around, my experience with rats (Dad used to breed 'em) is that it'd have to be one heckuva rat. The skritchy scratchy noises, okay, that could easily be a rat, but the thumps, the scrabbling footsteps...it'd have to be a giant among ratkind. El Gordo.*
Or the crawlspace could be set up in such a way as to amplify the sound. I can't discount that completely. Whatever it is, it's literally on the other side of the ceiling, and I generally am listening at night, so it's possible that it sounds bigger than it is. Still, the lack of any signs of ratty habitation puzzles me on that front.
My third guess is possum. It'd be an acrobatic feat, but wild animals seem to have an astonishing ability to squeeze themselves into tiny little holes that you'd swear they can't get in. I've mostly had experience with possums living under the house, but they can climb, so I can't rule out that somehow a possum found an overhanging tree and an entrance and has chosen to hole up directly over my head. It'd explain the timing and the apparent size of the thumping, I just don't know how likely it is.
Unlike Ben, I am, in all honesty, not all that bothered by the presence of this creature--it's not like I'm ever going to get into the crawlspace, and where I'd feel obligated to roust the beast in my own home, it's rather less of a priority in apartment living (although I really should mention it to maintenance in the interests of civic duty.) I'm more curious! What IS that thing? I want to know what I'm hearing!
Of course, I suppose I can't rule out roof ninjas...
*Which reminds me of a funny story about the days when my Dad bred rats...remind me sometime.