pilot whale vs tautog

pilot whale

noun
  • Either of two species of whale in the genus Globicephala, dark grey in colour. 

tautog

noun
  • A fish of the wrasse family found in salt water off of eastern North America from Nova Scotia to South Carolina (Tautoga onitis). 

How often have the words pilot whale and tautog occurred in a corpus of books? (source: Google Ngram Viewer )