I sometimes pity the humans who have no or one dog, because multiple dogs are more entertaining than the best movie or TV show. As for mentoring, I have no doubt they do teach each other, and Molly has been mentoring Shadow. She won't teach him anything from Dash, though, as she really didn't like him (Dash, that is). Oddly enough, though, Dash was my digger (learned it from his predecessor, Max, even though Max at the time was too old to dig any more), and Shadow likes to dig. He also has several habits that were unique to other dogs I have had in the past. Mentoring from the Bridge?