Quotation from: White Fang

Written by: Jack London

Then he took the trail, the lightened sled bounding along behind the
willing dogs; for they, too, knew that safety lay open in the gaining of
Fort McGurry. The wolves were now more open in their pursuit, trotting
sedately behind and ranging along on either side, their red tongues
lolling out, their lean sides showing the undulating ribs with every
movement. They were very lean, mere skin-bags stretched over bony
frames, with strings for muscles--so lean that Henry found it in his mind
to marvel that they still kept their feet and did not collapse forthright
in the snow.