bison vs cheetah

bison

noun
  • A large, wild bovid of the genus Bison. 

cheetah

noun
  • A distinctive member (Acinonyx jubatus) of the cat family, slightly smaller than the leopard, but with proportionately longer limbs and a smaller head; native to Africa and southeast Asia (where it is nearly extinct) and also credited with being the fastest terrestrial animal. 

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