My 8 month old male lab has been growling for months........if I pick up a newspaper and swat my hand with it to show him his behavior was wrong...he circles up and growls at me. I thought this would go away as he grew...but he is still doing it. He has not actually made the attempt to bite but I have to say I am a little fearful he might. Any suggestions ? My vet says a shock collar...but I am not a big fan of that. I have three other labs and never experienced this.