When a puppy comes to know that?

I don’t remember the exact day that I took this photo. I guess it was at the last September.

Don’t worry. This puppy was just sleeping, not dead.

He liked playing with pepole. He didn’t fear to human. All adult dogs that I see on streets seem fearing human. I wonder when and why they came to know that it’s better not to get too close with human.

Even though dogs fear human, they don’t go far away from us. They just live around human’s area. It is a history of dogs and us, isn’t it?