A good link here for Tony Hillerman's version of the Skinwalker: a review of his novel Skinwalkers. Not all of it useful for our purposes, but interesting, and may include some clues...
http://www99.epinions.com/review/Skinwalkers_by_Tony_Hillerman/content_449959464580
http://www99.epinions.com/review/Skinwalkers_by_Tony_Hillerman/content_449959464580