brood sow vs warthog

brood sow

noun
  • A female pig kept for breeding. 

  • A woman raising children. 

warthog

noun
  • A wild pig of the genus Phacochoerus, native to Africa. 

  • A nickname for the A-10 Thunderbolt II air support warplane 

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