They were originally bred and used as working dogs for fishermen in Newfoundland. Newfoundland dogs are known for their giant size, intelligence, tremendous strength, calm dispositions, and loyalty. Newfoundland dogs are known for their giant size, intelligence, tremendous strength, calm dispositions, and loyalty. They excel at water rescue/lifesaving because of their muscular build, thick double coat, webbed feet, and swimming abilities. In the water, the dog's massive webbed paws give it maximum propulsion. The swimming stroke is not an ordinary dog paddle: Unlike other dogs, the Newfoundland moves its limbs in a down-and-out motion giving more power to every stroke. The Newfoundland dog is known for its calm and docile nature and its strength. Newfoundlands are ideal companions in the world of therapy and are often referred to as the nanny dog. The breed was memorialized in 'Nana', the beloved guardian dog in J. M. Barrie's Peter Pan. The Newfoundland, in general, is good with other animals, but its size can cause problems if it is not trained.