There's a book called "Dogs never lie about love" (it's got some good scientific material in it, and some photos of laughing dogs - yes, really - on the cover), in which there's one observation that intrigues me. Briefly, when two dog-people meet, with their dogs, and speak, and then move on, the dogs go with their "owners". We've all seen it. The author remarks that dogs must be the only creature that prefer the company of another species to that of their own.