I currently have a 3 pound chihuahua. I am interested in getting a Great Dane from an animal shelter. I've always wanted one because I love their personalities and because they make great guard dogs (I'm a single female living alone in a first floor apartment). I've heard that as long as you exercise them outside daily, they are good apartment dogs since they're so laid back. My main concern, though, is that a Great Dane might accidentally hurt or kill my chihuahua while playing. Has anyone successfully had a small dog and big dog live together?