Some Dogs Have Dangerous “Locking Jaws” and Deadly Bite Pressure
This myth is usually started and spread by people who have had a bad experience with an ordinary dog or who just have a grudge against dogs or particular type or breed of dog. This dog ‘fact' says that some dogs have locking jaws that can't be disengaged if they bite. Furthermore, the myth usually suggests these dogs have incredibly high bite pressure, allowing them to bite through steel. Or something. Of course these are basically nonsense claims.
Some large dog breeds are stronger than others, naturally, and some dogs can be pretty determined when they latch onto something, if they want to. Remember: dogs don't have hands. Their mouths are really their only way to grab and hold something, and mostly, they're pretty good at it, but they are not supernatural lock-on biting machines!
There is scientific evidence to evaluate and quantify these facts, too. I. Lehr Brisbin, Ph.D., a researcher at the University of Georgia explains that even the breeds most-often targeted by this myth, pit bull-type dogs, don't have ‘locking jaws,' or any substantial difference in how their jaws work from any other kind of dog. What's more, at the time of the 2010 article where Brisbin debunked this claim, there had not been any studies done that measured the bite pressure of any dogs.
Dogs in a scared or aggressive posture can be frightening and a determined dog can hold on hard to what it bites, but a well-trained and well-mannered dog is loving and safe and even a little dog can deliver a serious bite, if it's mistreated, just like any animal.
Next, let's look at some myth-understandings surrounding the history of dogs and humanity as companions…