Thanks to everyone for their comments. A bit of a mystery to solve, I guess.
Linda, what I caught didn't quite look like a cotton rat. How large to do those get?
The one I caught and the one the dogs killed were near the size of a red squirrel. The one I caught was probably a smidgen larger. Very similar to the size of a healthy Norway rat. However, it didn't have the 'mean' look of those. The head was more rounded and the body a bit more oblong; the hair was smooth and tight, a bluish gray on top and a white on the belly. Norway rats have more of a sharp-featured face with more prominent ears, coarser hair and a rangier build. So in Google photos what I caught looks more like what is depicted when looking at 'water voles'. But...it definitely chews on plastic and wiring and when it selects something it continually attacks the same spot, e.g. the speedometer cable always chewed in the same place. Did no good to splice it because the splice was severed by the following day. Also, I've seen no hint of any tunnels, no rhizomes being eaten - just the foliage eaten low. I also haven't found any sign of shrubs being eaten. So I'm not quite sure. Eliminating just the two year before last brought all damage to an end. No more cable chewing, no further iris damage. That year was a bad year for house mice and/or field mice invading the garage. I did discover that a mouse caught in a trap would be cannibalized until only a bloody skeleton was left. That also stopped after the two were caught. This year I haven't seen any mice near the house. I wonder about that since they are plentiful in the pasture. I'd try poison, but am afraid of endangering the dogs and other things. Mostly I'm rather fond of most of those 'other things'. At least for the most part. It's really a new problem and it does seem worse when drought has caused a lack of green winter vegetation.
--- In email@example.com, Linda Mann <lmann@...> wrote:
> I never heard of any species of voles eating plastic & metal. That
> really does sound more like rats.
> Voles are pretty much vegetarians, unlike some other rodents. Voles are
> super at eating bark off small trees and roots.
> Did you get a good look at a corpse? Could they be cotton rats? I
> think they are mostly a little smaller than Norway rats, shorter tails.
> Not sure what you have in TX. But those are mostly vegetarian too, I
> Linda Mann east TN USA zone 7