My 5 month old puppy loves strangers, will he ever be a protector or deterrent to intruders?

I purchased a 5-month-old Mastiff in hopes of getting a companion who would also be a deterrent to intruders. I spent a whole lot of money on him and was able to watch both parents do protection work. My breeder assured me that he would be an excellent candidate for protection work but not sport since he’s a little sharp. (Though I don’t really want to do protection work, I just want a companion/deterrent dog.) My concern is that he isn’t very good at being a deterrent. Lol. It seems like nothing bothers him. He loves strangers, he won’t bark at anyone or anything. I had a stranger in my yard at night and he just stared at him lol He’s very calm and composed except for when we play tug. He is very aggressive when we play tug but he is just playing. I love him to death and wouldn’t trade him for the world. But my question is, will he ever develop into a natural deterrent dog or is that something that needs to be trained into him? Also, it may be my fault since I let everyone meet/pet him.

Cindy's Answer:

I wouldn't expect a 5 month old dog of any breed to be a deterrent. It would be like expecting a 6th-grade child to be a deterrent. I'd suggest watching some of our training material on raising a puppy that you want to be some type of working partner. The key is to teach him about the world, keeping in mind your goals.

I have a young German Shepherd male, I got him at 8 weeks and he's now 3. He's just now starting to really show some territorial behaviors at my house. I know his bloodlines mature slowly and the change in him over the last couple of months has been interesting.

If you don't want him to be overly social with people you don't know, then don't allow him to meet everyone. With puppies and young dogs I do condensed versions of the behaviors I will expect as adults. I work on our relationship and obedience skills in puppy sized lessons. I'll link some material for you below.