chimpanzee vs orangutan

chimpanzee

noun
  • Pan troglodytes, a species of great ape in the genus Pan, native to Africa, and believed by biologists to be the closest extant relative to humans along with the bonobo. 

  • A member of the genus Pan, including the bonobo which is also known as the pygmy chimpanzee. 

orangutan

noun
  • Any of three species of arboreal anthropoid ape, characterised by their shaggy reddish-brown coat and long arms, which comprise the genus Pongo; Pongo pygmaeus of Borneo, Pongo abelii of Sumatra or Pongo tapanuliensis of South Tapanuli (in Sumatra). 

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