One of our members had a buck that would constantly lick her son's skin. He thought it was because the buck loved him a lot... but then the buck started doing poorly (so poorly that she thought he was going to die), and it occurred to the owner that maybe he was licking the sweat off of him for the salt it contained.
Sure enough, with access to salt the behavior stopped and the buck improved rapidly.
He no longer licked her son, either, and he was devastated thinking that the buck no longer liked him.
Better than the alternative of losing the buck, of course, but mom had some 'splainin to do.