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 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. There are several health problems associated with Newfoundlands. There are several health problems associated with Newfoundlands. Newfoundlands are prone to hip dysplasia (a malformed ball and socket in the hip joint).