You may be right! Our little Boston Terrier could see her reflection in a mirror... she just got bored very quickly once she realized there was not another dog behind the mirror!
Sometime after we had to put our dog to sleep, my Mom got a little dog statuette at a rummage sale; it stood about a foot high, and looked just like a Scotch terrier, except for the color (which was blue-gray). It was posed like he was sitting on his haunches, with his head turned to the side; she put him on the floor, against a desk, just inside the front door of the house. As a joke, we put an old leather dog collar around his neck.
Well, you should have seen how confused neighbor dogs would get when they would come to visit. They'd look in the front door, and see what appeared to be a little dog looking back at them; except he wouldn't move! And, because of the collar, he must have smelled enough like a real dog to just make matters worse. There was actually one dog who kept trying to sneak up on the statue, and would sniff at it... when the statue wouldn't move, you could just see how freaked out the visitor dog would get! Poor thing just couldn't figure it out!