eared seal vs earless seal

eared seal

noun
  • A seal belonging in the Otariidae family; a fur seal or a sea lion, differing from the true seals in having small, visible ears and the ability to walk on land. 

earless seal

noun
  • Any of the seals in the taxonomic family Phocidae characterized by lacking external ear flaps; true seals. 

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