The Call of the Wild
How we cite our quotes:
All day Buck brooded by the pool or roamed restlessly about the camp. Death, as a cessation of movement, as a passing out and away from the lives of the living, he knew, and he knew John Thornton was dead. It left a great void in him, somewhat akin to hunger, but a void which ached and ached, and which food could not fill (7.41)
While Buck’s hunger is initially physical, is becomes emotional as a result of his love for Thornton.