They're entertaining me. These critters, though they're only riparian in the British Isles (Ratty in The Wind in the Willows) live a subterranean life across a swathe of Europe from, roughly, the Pyrenees to the Alps and on through Austria to, I think, parts of Hungary. They burrow like crazy, they reproduce similarly. They like wet soil and so have great fun under drip feed irrigation lines. Last year their burrows bonsai'd about half our summer plants, tomatoes, aubergines, peppers. No drip feed this year.

Oh, they are vectors of tapeworm and bubonic plague. Adds to the fun.