Smaller dogs with long noses, like miniature dachshunds and shiba inus, live the longest, according to an analysis of over 580,000 dogs in the UK. Meanwhile, medium-sized breeds, such as English bulldogs and shih tzus, are the shortest-lived.
“Despite the UK being a nation of dog lovers, we don’t have a great handle on our dog population in general, and more specifically, their expected lifespans,” says Kirsten McMillan at Dogs Trust, a welfare charity in the UK.
To conduct a comprehensive analysis of dog longevity, McMillan and her colleagues collected data from various sources, including vets, pet insurance companies and animal welfare charities. The data included 584,734 dogs belonging to 155 breeds, of which 284,734 were deceased.
The dogs had an average lifespan of 12.5 years. Female dogs had a slightly higher life expectancy of 12.7 years, compared with 12.4 years for males.
When sorted into categories based on their size and face shape, the team found that small, long-nosed dogs of both sexes had the highest life expectancy, surviving 13.3 years on average. With an expected lifespan of just 9.1 and 9.6 years old, male and female medium-sized, flat-faced dogs had the worst outcomes, respectively.
“Many flat-faced breeds, small or large, don’t do well, for example French bulldogs, St Bernards and presa canarios,” says McMillan.
Flat-faced dogs are known to face a range of health problems, including issues with breathing, digestion and even sleep, which may explain their shorter lives.
One of the most surprising findings was that purebreds had a greater life expectancy than crossbreeds, at 12.7 years compared with just 12 years.
“There has long been a belief that crossbred dogs are longer-lived than purebred dogs due to the concept of hybrid vigour,” says Audrey Ruple at Virginia Tech, who wasn’t involved in the study. This refers to the idea that hybrid animals or plants might be healthier because they have more variation in their genes – but this needs to be investigated further, says Ruple.
“Hopefully this study sparks more research into exactly why some breeds are dying young, and ultimately improves the lives of our dogs,” says McMillan.