As I mentioned in the previous thread, we lost the older of our 2 Shelties (Brittany) during the latter half of 2004 and brought a new Sheltie pup (Annabelle) home a few weeks later. Despite that, Bandit, who is 5 years old, went into a period of lethargy and depression. When we would go out in the RV, all he wanted to do was to lie under the dining table and sleep. At home, he would go in the foyer or under the breakfast table and sleep.
It has only been in the last month or so that we've noticed him returning to his former personality. He's coming out and wanting to be in the midst of the family activities more and more, and we notice him playing with Annabelle (who has always bugged him to no end with her puppy playfulness by biting his ears, jumping on his back, etc.) more as time passes.
And, yes, Bandit has taken on some of Brittany's traits. He now is responsible for barking at the vacuum cleaner, barking at me when I sneeze, and a number of other behaviors that Brittany had.