"The call still sounding in the depth of the forest filled Buck with a great unrest and strange desires... wild yearnings and stirrings for he knew not what. Sometimes he pursued the call in the forest, looking for it as thought it were a tangible thing. He would thrust his nose into the cool wood moss, or into the black soil where long grasses grew, and snort with joy at the fat earth smells; or he would crouch for hours, as if in concealment, behind fungus-covered trunks of fallen trees, wide-eyes and wide-eared to all that moved and sounded about him.

One night he sprang from sleep with a start. From the forest came the call, distinct and definite as never before - a long-drawn howl, like, yet unlike, and noise made by a husky dog. He sprang through the sleeping camp and in swift silence dashed through the woods. As he drew closer to the cry he went more slowly, with caution in every movement, till he came to an open place among the trees, and looking out saw, erect on haunches, with nose pointed to the sky, a long, lean, timber wolf."

-Call of the Wild, Jack London 1903