The typical lifespan of an Irish Wolfhound is 6-8 years. Typical lifespan of an Old English Mastiff, Great Dane, Greater Swiss Mountain Dog, or Leonberger is 6-10 years. Typical lifespan of a Bloodhound or Bullmastiff is 7-9 years. Typical lifespan of a Dogue de Bordeaux, Newfoundland, or St. Bernard is 8-10 years.