Here are two very powerful working dogs breeds: The Newfoundland and the Rottweiler.
Some authorities lay claim he is descended from Great Pyrenees dogs brought by Basque fishermen to the coast of Newfoundland; others consider his ancestors are French Boarhounds. An exceptionally powerful swimmer, it has saved many shipwrecked individuals from drowning. Strength is his trademark, together with a funny rolling gait. The body is strongly built and well-boned, the forelegs straight, the hind legs brawny and well-muscled. The head is massive having a broad skull, the muzzle broad and deep, eyes dark and deep-set, and small ears set well backand lying near the head. The tail drops straight or with a slight curve, while the coat is quite heavy and weather-resistant.
WEIGHT: 100-150 pounds
HEIGHT: 26-28 inches
COLOR: black, or white and black (Landseer).
When Roman legions got across the Alps almost 2,000 years ago, they employed this breed's Mastiff-type ancestors as guards and cattle drovers. In time
WEIGHT: 85-110 pounds
HEIGHT: males 24-27 inches; females 22-25 inches
COLOR: black with rust to mahogany markings.