den vs habitat

den

noun
  • A squalid or wretched place; a haunt. 

  • Synonym of fort (“structure improvised from furniture, etc. for playing games.”) 

  • A comfortable room not used for formal entertaining. 

  • A group of Cub Scouts of the same age who work on projects together. 

  • A small cavern or hollow place in the side of a hill, or among rocks; especially, a cave used by a wild animal for shelter or concealment. 

verb
  • To ensconce or hide oneself in (or as in) a den. 

habitat

noun
  • A place in which a person lives. 

  • Conditions suitable for an organism or population of organisms to live. 

  • A terrestrial or aquatic area distinguished by geographic, abiotic and biotic features, whether entirely natural or semi-natural. 

  • A place or type of site where an organism or population naturally occurs. 

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