When you have an old house with a mail slot, rather than a mailbox, you don't have to pay any attention to your mail until the drifts begin to block access to the front door, or until someone shuts off your utilities. Hoping to head-off the latter, this evening I began one of my occasional excavations. Deposited here and there in the accumulated strata of junk mail were the dreaded bills, but also a few unexpected gems in the form of holiday cards, obsolete now, some would say, but I prefer to think of them as aged to perfection.
Significantly, one was from Margaret & David Bamberger. In it, Margaret said she'd read my blog post "Geminids and Mysteries" and "[...] when I read about your mystery critter I had to laugh because when we were camping one time a similar thing happened. After being awake for a while wondering if I should hide in the truck because I couldn't imagine what was out there, I finally figured out that a bunch of feral pigs were hanging out doing god knows what."
That's the best identification of my mystery critters suggested so far, and I'm inclined to accept it. So, now I know. Probably.