Ah, turns out this one is Swedish. Spotted another one, completely identical, with a very old-looking Made In Sweden label and an even older-looking cork stopper with metal ring - so probably c.1920s-30s in date.
A small note on the Holmegaard fyldehund / snapsehund decanters: They produced them with both clear and coloured eyes, and with straight legs, rather than the looped legs seen above. Production appears to have started no earlier than 1920.
They re-issued both the pigs and the dogs in the mid-late 1970s, both with clear eyes only. From what I've ascertained, these newer ones were only available direct from the factory, as they don't appear in the catalogues. They're distinguishable from the originals by dint of a signature - 'HG' +a single digit year code.
Attached example is from 1977.