dunter

noun2

1. •
   The common eider, Somateria mollissima.
2. •
   (dialect, Scotland) A porpoise.

   • "Here an old woman, thinking to help her pastor out of a dead lift, cried out, 'Aiblins, Sir, it was a dunter.' (The vulgar name of a species of whale common to the Scotch coast.) — 1845