German Shepherd - force bite 260 pounds won't crush your bones, but it will be enough pain to immobilize you and cause tissue/blood vessel damage.
I know firsthand, when I was a kid with a paper route a Shepherd flew out of a garage, grabbed my ankle and pulled me off my bike like a rag doll, luckily the bites were not severe and we were friends with the family so that was the end of it. Our last dog was a Shepherd, the most intelligent dog we've had by far, we had her trained to search the whole house on command, my wife and me really loved her. still miss her 5 yrs later...
