I think whether or not a dog will protect without any training, depends on the individual dog.
When I was 14, I finally talked my Mom into letting me get a dog. I rescued a small female mixed breed, she looked like a tiny Labrador mix, that weighed about 20 lbs.
This girl loved everybody. She and I walked many miles together and met many people. She never barked or growled at a single one, until one day...
I live in a tourist area, Myrtle Beach, SC and my parents owned a small motel. We lived on the premises, right on the boulevard. On the street behind our motel was a Greek Restaurant. The owner had kids who were my friends and they were at this restaurant most days in the Summer. We used to sit on the brick wall that separated the restaurant from the lot next to it. Making a long story short, their was a Greek cook there that was very creepy and didn't speak English. There was something in the way that he looked at you that made me feel uncomfortable.
While sitting on this wall one day, he comes out and he comes up to us kids and he's looking at me. I have my dog with me. As he walks closer, my girl tenses and emits a low growl. He proceeds to put his hand on my bare leg and all hell broke loose. My tiny 20lb girl threw herself off the wall at him snarling and biting. I was in shock. She chased him as he ran into the restaurants back door.
I was terrified that I was going to get into trouble and that someone would take my dog and put her down. I got her and took her home.
The end of the story is that nothing happened to me or my girl and the owner fired the worker after hearing what his kids told him.
My sweet girl never growled at another person from that day on. She lived to the ripe old age of 17. I had to put her down when I was 31. One of the hardest things I had ever had to do.
I've heard this saying of it doesn't matter the size of the dog in the fight, but the fight in the dog. My little girl proved that.
On another note, I agree with the others that the size and breed of your sweet Jack is most likely to keep you from harm.
I don't know if my girl Jazzy would protect me and I hope she and I are never in the position to find out.
Please post some pictures of your babies. We love pictures!
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