Coming from a dog trainer perspective this thread is hard to read sometimes. Young animals in our care need to be raised, proactively, and given the responsibility of choices as they show maturity and competency. They aren't born knowing how to navigate human imposed rules and boundaries. Especially when those rules are opposite from thier instincts and species programming. New instincts and feelings are activated in the brain all during different developmental stages for the first two years + especially. If you arent watching for and prepared to guide your pup through these new intense impulses as they grow through them sucky problems are going to happen. Trainers breeders and veterinarians need to do better job getting this information into the hands of new puppy owners so misunderstandings like this stop happening. It's heartbreaking for everyone.
For example, a big spike in sudden predatory behavior often correlates with "first spring as an adolescent" dog. So depending on when you get your dog, that can be almost a year and a half into having them. A lot of people feel settled and sure about their dogs behavior and temperament by that point if they are not expecting this "out of nowhere" sudden predatory behavior. Of course it isn't out of nowhere; it's simply an increase in external stimulus (spring, windows open, mating behavior, more animal activity outdoors) coinciding with an internal enviroment higher in motivation (hormones, maturing drives, developmental windows opening) that creates the convergence necessary for new motor patterns to be expressed. If people KNOW to watch for and expect this shift, they can be more prepared to contain, supervise, and train their dog through this normal and typical change.
Dogs don't really hit real social maturity and stability until about 4 years old. I often see "four year old dog free to good home" ads. Usually this means "first bite to a human" behavior. The warning signs were probably there all along but because "he never bites" it was ignored and people got comfortable with it. They didn't realize the dog still hadn't hit maturity to fully express the motor pattern sequence up through now actually biting. It's sobering to most people to realize you can not assume your adult dog is likely to be what you see as a puppy or adolescent dog. People still think getting them as a puppy is a guarantee they'll be good with kids or animals when they mature. It's more accurate to see their adult (over 4 yrs) parents and siblings to get an idea of what you will end up with. I personally try not to get puppies that were bred from young dogs themselves. NO ONE knows yet what any of those dogs are going to end up being like for sure.
