There is really some bad information in this thread.
First, many of you need to disabuse yourself of these romantic breed descriptions. Although some general descriptions of temperament and behavior or “generally” true, most are very misleading. Things like, loyal, “one family dog”, “natural” guardian and the like are romantic marketing speak and nothing more. First, most breeds are “loyal” because you feed and provide care; stop feeding them and see how loyal they are.
Next, this thread is really taking the wrong track. There are no “natural protectors”. There are breeds that do exhibit a better skill set for protection work, but you cannot go buy a puppy “out of the box” and expect that you will have such a dog. Unless you’re a professional, or a serious hobbyist, you’re better off thinking of a dog as an alarm or a deterrent and nothing more. There are definitely breeds that generally do not suffer strangers (Caucasion and it variants - known by different names, the Fila comes to mind) but those dogs can be very dangerous and are not appropriate for the average family or owner. Some of those dogs WILL bite and not always appropriately so. Are you prepared to live with that?
Many of the breeds mentioned here are simply not appropriate if you’re serious about a protection dog. The fact is, professionals take great care to select a breed and a young candidate and those dogs STILL wash out. A dog that may take a bite, may not stand up to stress or a fight. Many dogs cannot handle stress and don’t have the nerve to be true trained guard dogs. Many breeds mentioned here, particularly mollossers, are not particularly tractable, and being tractable is a must for protection work, lest you end up with a dog that will happily bite, but not take orders.
Many of you, like most dog owners, suffer from romantic notions of what your dog would do, but I assure you, that push come to shove, you are likely wrong. I’ve seen it time and time again when people take their dogs to various forms of protection training. I’ve seen it time and time again when people attempt to take their “show bred” working breed out to attempt to hunt. It’s a world of difference between a dog putting up a threat display to someone that is scared, and quite another thing for that dog to stay in the fight when that person is fighting the dog back and doing it harm. It takes a remarkable specimen to stand the rigors of protection training and come out the other end a reliable trustworthy protector.
What does all that mean? It means you are very unlikely to ever own such a dog unless you’re a professional or a very serious hobbyist. So get it out of your mind. Choose the breed you like, based on solid research for compatibility with you and your family, and be happy with it. You want protection? Lock your doors and take other appropriate safety measures and be happy your dog may deter a break in and may bark to warn you. And that’s all.
Random thoughts; there are no 250 lbs rotts unless they are grossly fat. There are not 140 lb GSD’s that can be used to work. 140lb is too big for a serious working GSD. Rhodesians cannot take down a lion single handledly - lmfao at that one. Many dogs mentioned here like Cane Corso’s and other mollossers have been bred for so long for show (in other words, bred for “beauty” without regard to much else), that they are worthless as serious protection trained candidates. You need only look no further than what professionals use when they want a protection breed. Overwhelmingly that is the GSD, malinois, and a few other select breeds. You do not find any mollosser in serious number and they would be the exception to the rule. Many mollosser breeds however make wonderful pets (properly bred) and will be a terrific visual deterrent and “sound the alarm”. Most mollosser breeds were working dogs and had a vocation. Sadly, none can do it anymore. For instance, the Presa Canario cannot even be called such because the modern day iteration of the breed is what they THINK the original was. I’ve wild boar hunted for 20 years now and have never seen a Presa engage or catch a hog, and I’ve seen a few try. Same with Cane Corso. I’ve seen more than my fair share of Cane Corso’s take a crack at protection training and most turned out to be weak nerved curs. And a weak nerved dog that has been trained to bite is a huge liability. I could go on and on and on.
So, if you’re serious about a protection dog, you need to think about the proper candidate breed first, but a close second is how that dog is bred. You simply cannot go to a show breeder and expect to get a serious working candidate. Show breeds and the hobbyist have done more to ruin dogs than anything else. If you want a serious working candidate, you need serious working parents and grandparents behind it. And you’d be lucky if such a breeder would sell a pet owner such a dog. I own and breed pitbulls and patterdale terriers. You could not show up with a fist full of money and buy a dog from me. They are not for sale. And most serious breeders of working dogs have high standards about who they will sell a dog to. I’d give a dog to another hunter or enthusiast before I’d sell one to a stranger - and most serious breeders feel the same way. And keep in mind, even getting a young pup or dog from a working dog breeder is not a guarantee. of success. The difference between the professional and you is that a professional will get rid of a dog that has washed out. A pet owner however is very unlikely to part with a dog it has bonded with. That’s why your chances of ever owning such a dog are slim. It’s why a thread like this, among pet owners, should be very realistic and geared toward what MOST any breed will do - provide an alarm - not save the day like in some movie or some newspaper clip.
Simply put, at the end of the day, most dogs are dogs, romantic breed descriptions aside. Are there differences? Yes, but they are largely overstated. They are canines, first and foremost and exhibit many of the same traits. Do they have different strengths and weaknesses, different temperaments? Sure. But most any dog will bond with its family and be “loyal”. And sorry to tell you, most dogs will happily change ownership when properly cared for by the new owner. This one owner dogs stuff is largely crap. Dogs are not people, so you’d be well advised to refrain from implying human characteristics to a dog (anthropomorphism). Dogs want shelter and food. Give them both and they will “love” you. They will also “love” someone else that does likewise.
Most of you here could never handle a serious working dog - and you wouldn’t want to. As I said before, a dog that will bite, even a dog that is trained to bite, is a huge responsibility and liability. 99% of you here will be fine with a dog that barks or a dog that looks like it will bite. I know this is a difficult subject for much to grasp. There is some terrible “marketing” information out there about various breeds. But trust me, I’ve bred dogs seriously for 20 years - and I know working dogs cold. I have some of the finest blood for my breed, and even they wash out, time and time again. I know serious protection enthusiasts and professionals, and not many dogs, no matter what breed, can stand up to serious protection training. Some do better than others - like I said, GSD’s, malinois, etc. - just look at what the professionals use (Police, Military, serious hobbyist). A dog that has started protection training and was not up to par, is a potentially dangerous animal. You know have a dog that has been trained it is okay to bite people, but doesn’t have the various other qualities to be trusted with that ability.
There is some good information in this thread and some very bad information. I don’t have time to pick thru it all. But I’d be happy to answer specific questions here or via PM.