feral cat vs house cat

feral cat

noun
  • A domestic cat that has returned to or was born in a living situation without human care. 

house cat

noun
  • A pet cat that is confined to, or almost permanently resides, inside the house. 

  • A domestic cat, Felis catus or Felis silvestris catus, commonly kept as a pet animal. 

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