SALT LICK SUBSTITUTE (porcupine) Image Size: 9" x 12" Original watercolor & gouache painting SOLD Signed & Numbered limited edition size: 200 - $80 Artist's Proofs limited edition size: 20 - $110 Porcupines will chew on anything that has salt transferred by the touch of a human. This 'porky has discovered that a pair of leather boots carelessly left outdoors make an excellent salt lick.