European bison vs buffalo

European bison

noun
  • The wisent, species Bison bonasus, Europe's heaviest land animal. 

buffalo

noun
  • A related North American animal, the American bison, Bison bison. 

  • The buffalo fish (Ictiobus spp.). 

  • Any of the Old World mammals of the family Bovidae, such as the Cape buffalo, Syncerus caffer, or the water buffalo Bubalus bubalis. 

  • A nickel. 

verb
  • To outwit, confuse, deceive, or intimidate. 

  • To hunt buffalo. 

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