The thought of animals as companions only was not a foreign concept, however. We owned several dogs and cats that shared our household. For a brief part of college and the several years of Vermont apartment life, I did not have animal roommates. Now, though, I find myself with two cats and one dog (plus a tank teeming with guppies) and I am feeling more like a "parent" as I referee their interactions and prevent broken belongings.
For several years, I enjoyed (for the most part) the dynamics between Scooby and Lilly, which were isolated incidents of "wrestling" and Lilly chasing Scooby. With the addition of Ziva, the barn rescue kitten, it has changed the household completely. She definitely has a personality, and Lilly and Scooby each interact with her in their own way.
Lilly loves wrestling with Ziva, and despite the David-and-Goliath nature of the match-up, Ziva seems to enjoy it as well. In fact, I heard her purr as she bites, claws and twists to get away from the dog. Lilly tends to initiate contact with the kitten. Scooby, on the other hand, tries to avoid the kitten at all costs. Recently I did see him willingly chase her. I haven't decided if it is out of playfulness or maliciousness yet. The following photo was taken just after he hit her in the face, but he doesn't look overly upset.