pelage vs winter coat

pelage

noun
  • fur, or any other form of the coat of a mammal 

winter coat

noun
  • An animal's seasonal appearance in winter, notably thicker and/or otherwise camouflaged plumage or fur after (often autumnal) moulting 

  • A warm coat, often an overcoat, fit to be worn in winter 

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