I used to know someone who owned a Great Dane. If that dog stood on it's hind legs, it would scare people just because of it's size.
And, I used to own a black Cocker, Ebony. (I still miss her.) She was not much on barking, but when she did, if you didn't know what kind of dog I had, you'd think she was much bigger! She didn't sound like a smaller dog. She was one of those dogs that people just couldn't help respond to. I only ever once saw someone not smile. You would think that she wasn't much for protection, but you'd be wrong. One day, the neighbor asked what she'd do if I was attacked. I didn't have a clue, so he acted like he was going to hurt me. She threw herself against my legs, and turned snarling at him.
When my hubby and I got married, she went w/me. One day, he brought me home a kitten. From the getgo, that was her cat. If you messed w/Smokey, you had to answer to Ebony. The neighbors had a Rottweiler. I couldn't stand that dog! It was always in our yard. It even came up on our porch once and peed on my hubby's shirt and lunch box that he had just put down. The neighbor was standing right there, and never said a thing.

One day, the Rotty came into our yard, and started to chase Smokey. Next thing you knew, there was a black streak running across the yard. Ebony chased the Rotty out of our yard, back where it belong!