If you haven't seen the documentary on Netflix called THE MIND OF A DOG I would certainly recommend it-- it does actually have a few Shelties in it but it is a wonderful mash of information, good for anyone who like dogs and the relationship they have with us. I was interested to find out one of the major differences between wolves and dogs was the sclera-- made lots of sense in all sorts of way and if you want to know as well-- watch the movie