people when they leave HELP? Okay so my 8 year old jack russell terrier starts growling viciously and trying to attack people when they leave and enter the house. He started off just chasing people and trying to bite their ankles. He NEVER EVER did this before he would only bark at people when they enter now hes just out of control. He was always sweet and never bit anyone. Now he keeps trying to attack my sisters boyfriend who has lived here for about 8 months and he just started trying to attack him. Every time he comes home now toby starts growling and I put him in his cage. He lunged off the couch and bit him the other day when I wasn't home. I have no idea why he is doing this and he has been getting progressively worse. He even tries to chase my sister out of the house and my mom when she goes to the door. Is he just being territorial or is it because hes getting old? Would a temperament shot help? What should I do?