There's a crease or skin-fold going down the left hind leg. Try to move that crease in, so it's in the fold between the leg and the body. The conventional wisdom from the 19th century was that these animals had to have skin that looked like pachyderms (grey). However, recently they have theorized that the skin had to show seasonal variations in color, as well as differing colors depending on sexual condition, health or mood. Like birds or lizards.