cave painting vs doodles

cave painting

noun
  • The paintings resulting from this activity regarded collectively, especially if prehistoric; cave art; (countable) an individual painting of this type. 

  • The activity of applying pigments to the interior surfaces of caves to create images, especially when carried out in prehistoric times. 

doodles

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