I had a Jack Russell terrier that would take on anything movin. He liked me, Linda, my mother, and my oldest son. Anybody else, I had to watch him like a hawk.
He didn't bluff, if you were trespassing he'd nail you as soon as he got there. He'd kill snakes, cats, "anything".
I have a life long friend thats about 6'2", weighs about 300, and a super guy. Huff hated him, and his size didn't didn't scare ole Huff a bit.
Damn I miss that dog. He was ornery, but he always protected the family.