I've had my SPCA mutt, Peppi, for about 2 1/2 years now. The amount of knowledge he has accumulated in just the past 6 months absolutely amazes me. Cars come and go all the time. People walk up and down the street. He knows who is who. He used to be indiscriminate in his reactions. Not anymore. He now has everyone sorted out. If a neighbor pulls up in their car, he doesn't move an inch. If a UPS truck pulls up, he goes nuts. If the postman walks down the other side of the street, even while the TV...