Our puppy is 9 weeks old. He will crouch down low and "stalk" my 3 year old son then pounce up on him and try and bite on him. Sometimes while he is tying to bite him he is growling but I think its all play? I cannot let my son play on the floor without the dog tying to bite him (and he bites HARD) This is our first puppy, I did expect some biting and chewing and what not but is this normal? We tell him no and remove the puppy (Fred is his name ) but he will not stop. Any idea when this will calm down? Thanks!