Cervus elaphus vs elk

Cervus elaphus

elk

noun
  • Any moose (Alces alces), the largest member of the deer family. 

  • Any of the subspecies of the moose (Alces alces, alternatively named Eurasian elk to avoid confusion with the wapiti), that occurs only in Europe and Asia. 

  • common wapiti (Cervus canadensis), the second largest member of the deer family, once thought to be a subspecies of red deer. 

  • Sambar (Cervus unicolor). 

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