The differences between a newborn puppy and one that is almost three weeks old are staggering. Not only have their eyes and ears unsealed, but they exhibit behaviors that reflect the massive development occurring in their brains. Mouthing is a big one, as they are exploring everything in their environment: themselves, each other, the surfaces beneath their paws, the gates, and the novel items we add on a daily basis. They also begin engaging in a social way, seeking out each other to play and se