What dog is the most vicious?
This might sound funny but little dogs such as a Terrier will act more dominent then a big dog such as a Doberman, I for one have owned both at the same time and my Doberman let my Terrier push him around. My Terrier actually was very protective of his food and did not like to be touched and would growl if you had anything to do with anything you touching him or food. My Doberman will let you do anything to him and you can put your hand in his mouth and him just lays there like it’s no big deal. I have heard of many cases like these and have seen them. So to your question little dogs are actually more vicious then bigger dogs, usually.
