Customs are not exclusive to humans. Puppies also have clear certain concepts: Leaf bacon is delicious, cats scratch and glass doors are very dangerous. <br /> <br />So while the masters are doing work at home and have left only the door frame, the animals are wary cautious, preferring to wait for someone to open the door to pass. Because man is the only animal that stumbles twice on the same stone. Dogs do not take risks, and less if there are any human recorded.
