Heathen vs vertebrate

Heathen

adj

  • Pertaining or adhering to the Germanic neo-pagan faith Heathenry. 

noun

  • An adherent of the Germanic neo-pagan faith of Heathenry. 

vertebrate

adj

  • Having a backbone. 

noun

  • An animal having a backbone. 

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