Remember, diet and lifestyle have a huge impact on a dog's lifespan, just like ours. Charley had a Bull Mastiff, Joe, who was around 5 years old when he rescued him according to the vet's estimate, and he had Joe for another 10 years or so!
Oh, lol! I'm watching Shiva pat Bimmer on the head with her big ol' foot and I'm thinking her life span may not be so long if she doesn't cool it . . .