Rottweiler

A Mastiff named Zorba is considered to have been the heaviest dog in the world, weighing in at 343 lbs., and is listed as such in the 1989 Guinness Book of World Records.

The Doberman is a large, fearless dog that is well-known for its historically common job as a guard dog. Originating in Germany, the Doberman Pinscher is highly intelligent and loyal, and is well suited for police work, tracking, and competitive obedience. At home, these dogs are sweet, affectionate, and thrive on human companionship. Dobermans are usually excellent with children and other pets, and are consistently ranked among the AKC’s most popular dog breeds.

The Neapolitan Mastiff is a noble, astounding dog. This breed was originally bred in Italy and was commonly used as a guard dog, meant to deter intruders with its intimidating look and size. Quick to learn and excellent with their families and children, the Neapolitan Mastiff is protective and devoted, generally has a low energy level, and has abundant, hanging wrinkles and folds on its head. These dignified, powerful dogs weigh between 130 and 155 lbs. in adulthood, and thrive when given plenty of property to roam and defend.

Tosa has been known in Japan for almost a 1000 years by now. He was bred as a fighting dog, so he’s probably not the best choice for an inexperienced owner. This breed is normally a well-mannered and peaceful dog for his family, but it has already shown aggression towards other dogs in some cases. He is reserved with strangers, but not necessarily aggressive to people. This breed is definitely a fearless protector and guardian dog. Tosa can behave well with small children if he gets very early training and socialization, but rough play should be avoided because of his fighting instincts. Tosa is intelligent and very easy to be trained. He has a low energy level. The average weight of this breed is 100 to 200 pounds, and its size is about 22 to 24 inches.