ferret vs mustela

ferret

noun
  • The black-footed ferret, Mustela nigripes. 

  • A diligent searcher. 

  • An often domesticated mammal (Mustela putorius furo) rather like a weasel, descended from the polecat and often trained to hunt burrowing animals. 

verb
  • To uncover and bring to light by searching; usually to ferret out. 

  • To hunt game with ferrets. 

mustela

noun
  • Any of the carnivorous mammals of the genus Mustela. 

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