polecat vs stoat

polecat

noun
  • A weasel-like animal of the genus Mustela. 

  • A tubular device used to support lights on a set. 

  • notably, the European polecat, Mustela putorius. 

  • A skunk. 

stoat

noun
  • Mustela erminea, the ermine or short-tailed weasel, a mustelid native to Eurasia and North America, distinguished from the least weasel by its larger size and longer tail with a prominent black tip. 

How often have the words polecat and stoat occurred in a corpus of books? (source: Google Ngram Viewer )