rockyp11 asked: he is a 12 wks old chihuahua/rat terrier mix/ He can be so sweet, until he does not get his way. Today he broke the skin on my hand because I would not let him go down thru the yard to neighbors house. He can be vicious when he cannot do what he wants at the moment. Any help would be appreciated. I watch dog whisperer religiously! I tried putting him down on ground and “biting” him with my hand. He does NOT lay there peacably like you see on the show! I know he should be walked a long time every day, but he attacks my leg!! I might have to get him a muzzle. I am looking for a good dog training class now.First thing I found out is he should not be sleeping on my bed. Hope we get some sleep tonight!!! thanks everybody for your help. I took his toys away from him, his food, and he is now sleeping on the floor and not allowed on the couch. I make him sit/stay to get a toy or food. He looks so sad, but I will stick to this so he can become a well behaved member of the family. I am calling Tuesday to get into a class that will help with aggression. You have been a big help to me. I never had a dominant aggressive dog before, and I have had a few dogs in my lifetime! This is a first. a rat terrier is very close to a fox terrier and a jack russell. my puppy is rat terrier/chihuahua. I was given him for a birthday present. He was being sold at a flea market by the amish. do not know his background. He is still pretty sad, but I just took him for a walk and he was very good! I will keep this up and keep a positive attitude!!