mammal vs wild animal

mammal

noun
  • An animal of the class Mammalia, characterized by being warm-blooded, having hair and producing milk with which to feed its young. 

  • A vertebrate with three bones in the inner ear and one in the jaw. 

wild animal

noun
  • Any animal living in a natural, undomesticated state. 

  • One exhibiting uncontrolled behaviour. 

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