Study finds small, long-nosed dogs live the longest

Small, long-nosed (or dolichocephalic) dog breeds such as Whippets have the highest life expectancies in the UK, while male dogs from medium-sized flat-faced (or brachycephalic) breeds such as English Bulldogs have the lowest. The results, published in Scientific Reports, have been calculated from data on over 580,000 individual dogs from over 150 different breeds, and could help to identify those dogs most at risk of an early death.

Kirsten McMillan and colleagues assembled a database of 584,734 individual dogs using data from 18 different UK sources, including breed registries, vets, pet insurance companies, animal welfare charities, and academic institutions.

Dogs were from one of 155 pure breeds or classified as a crossbreed, and 284,734 of the dogs had died before being added to the database. Breed, sex, date of birth, and date of death (if applicable) were included for all dogs.

Purebred dogs were assigned to size (small, medium, or large) and head shape (brachycephalic or short-nosed, mesocephalic or medium-nosed, and dolichocephalic or long-nosed) categories based on kennel club literature. The median life expectancy was then calculated for all breeds individually and for the crossbreed group, then finally for each combination of sex, size, and head shape.

Small dolichocephalic breeds of both sexes (such as Miniature Dachshunds and Shetland Sheepdogs) had the highest median life expectancies of 13.3 years. Meanwhile, medium brachycephalic breeds had the lowest median life expectancies, of 9.1 years for males and 9.6 years for females.

Among the 12 most popular breeds, which accounted for more than 50% of all recorded pure breeds in the database, Labradors had a median life expectancy of 13.1 years, Jack Russell Terriers had a median life expectancy of 13.3 years, and Cavalier King Charles Spaniels had a median life expectancy of 11.8 years.

Pure breeds had a higher median life expectancy than crossbreeds (12.7 years compared to 12.0 years), while female dogs had a slightly higher median life expectancy than males (12.7 years compared to 12.4 years).

The authors note that their results are representative for UK dogs only, and that crossbreeds were strictly defined as any dog that was not a kennel club purebred breed.

They suggest that future research should investigate 'designer breeds' such as Labradoodles and Cockapoos separately to account for differing levels of genetic diversity between these dogs and mongrels.