I had some dorkwad stranger on the sidewalk grab my Staffordshire Terrier by her face one day and she bout ripped his freakin head off. I was laughing so hard. I said “ well, what did you think she would do?”
Same thing with my dogs. They are cow dogs, so when someone bends over to look at them, they seem like a cow that is dropping its head to challenge them. The dogs react and freak the person out. They haven’t a clue what they are doing.
Don’t know, but my approach to a dog, at their owner’s permission, is to get to their level, speak softly and extend the back of my hand for them to smell. That’s before I reach out to pet them.
I’ve have two small dogs, a poodle-dachshund and a poodle who-knows-what. Both smart, loveable dogs.