pinniped vs sealskin

pinniped

noun
  • Any of various large marine mammals belonging to the superfamily (formerly considered a suborder) Pinnipedia comprising walruses, eared seals and earless seals. 

adj
  • Pertaining to or similar to such a mammal. 

sealskin

noun
  • A type of fabric made from the skin of seals. 

  • An item of clothing made from sealskin (whether real or imitation). 

  • Any fabric manufactured to resemble sealskin. 

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