Lifespan

In 2013, a study found that mixed-breed dogs live on average 1.2 years longer than purebred dogs. Increasing body-weight was negatively correlated with longevity (i.e., the heavier the dog, the shorter its lifespan).[56]

The typical lifespan of dogs varies widely among breeds, but for most, the median longevity, the age at which half the dogs in a population have died and half are still alive, ranges from 10 to 13 years.[57][58][59][60] Individual dogs may live well beyond the median age of their breed.

The breed with the shortest lifespan (among breeds for which there is a questionnaire survey with a reasonable sample size) is the Dogue de Bordeaux, with a median longevity of about 5.2 years. Still, several breeds, including Miniature Bull Terriers, Bloodhounds and Irish Wolfhounds are nearly as short-lived, with median longevities of 6 to 7 years.[60]

The longest-lived breeds, including Toy Poodles, Japanese Spitz, Border Terriers and Tibetan Spaniels, have median longevities of 14 to 15 years.[60]

The median longevity of mixed-breed dogs, taken as an average of all sizes, is one or more years longer than that of purebred dogs when all breeds are averaged.[58][59][60][61] The longest-lived dog was “Bluey,” an Australian Cattle Dog who died in 1939 at 29.5 years of age.[62][63]