sea lion vs sea-lion

sea lion

noun
  • A steamer transporting cattle from the ports of Texas. 

  • A monster consisting of the upper part of a lion combined with the tail of a fish. 

  • A cow or bull transported by steamer from the ports of Texas. 

  • A marine mammal of any of several genera in the family Otariidae (the eared seals). 

sea-lion

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