The Bear by Marian Engel (McClelland and Stewart, 1976)

 

A strange and disturbing novel about a young Canadian woman who leaves her solitary academic life working for a historical society in Toronto to catalog the contents of a house located on an island in a river in the Canadian wilderness.  She lives alone in the house for the summer, and has an affair with a bear who had been kept in captivity there.  The bear is an excellent lover, and the woman enjoys her solitary life and the bear's good company, but must leave this idyll life behind when autumn arrives and she is forced to return to her passionless urban life.

Engel writes about the woman's relationship with the bear in a wonderfully matter-of-fact fashion, and the inter-species amour is believable and poignant (and quite erotic, as well).