These dogs are large and muscular and can be difficult to control as adults if they are not trained to respond to their owner's commands. Guarding dogs all have large heads and jaws. Dog bites from larger breeds are more severe than bites from smaller dogs because of the size of the injuries and the dog's ability to knock a person down during an attack. A large dog attack is just significantly more dangerous. Purebred and mixed breed dogs attack people every year.
Dog bites are a serious health problem.
A large number of small children are bitten by dogs they know while visiting the dog's home. Media reports lead the public to believe that packs of roaming Pit Bulls are more likely to bite than the neighborhood dog on his leash. However, the dogs most often responsible for severe bites to humans, especially children, in the US are Labrador Retrievers and German Shepherds and mixes of these breeds. These breeds are the most commonly owned dogs according to AKC registrations and dog licensing records. Increased popularity of guarding and fighting dogs measured by AKC registration growth, indicates that these dogs are becoming the most commonly owned breeds.