carabao vs water buffalo

carabao

noun
  • A domesticated subspecies of water buffalo, Bubalus bubalis carabanesis. 

water buffalo

noun
  • A large ungulate, widely used as a domestic animal in Asia, South America. North Africa and Europe: Bubalus bubalis. 

  • A water tank mounted on a trailer to be towed by a motor vehicle. 

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