Zac, is a collie dog belonging to my cousin Jim in Aghincurk, Northern Ireland. He is old and blind. I met him in 2010.
When I knocked at the door, the four other collies, that I had not met barked but Zac did not. He could pick up my scent through the door and knew me from 2010. I do not play with him, but give him lots of pats and he likes to lie on my feet.