Hybrid Origin: The Saint Bermastiff is a hybrid between the Saint Bernard and the Mastiff. Erroneous Alias: Saint Mastiff Country of Origin: Saint Bermastiffs originate in the United States of America. Original Purpose: The Saint Bermastiff is a companion for older children and adults. Breed Characteristics: Saint Bermastiffs generally are very large boned, short, wide bodied with a deep wide chest. The Saint Bermastiff tend to be calm, easy going and loving. Saint Bermastiffs are commonly curious and eager to please. Life Expectancy: Average life expectancy for the Saint Bermastiff is 10 - 13 years.