A dog may well be for life, not just for Christmas, but how long that life is depends very much on the breed, according to a new study.

       Jack Russell terriers have the longest life expectancy, living for almost 13 years on average, which is almost three times as long as some of the ultra-trendy, flat-faced dogs favoured by social media fashionistas.

       French bulldogs, a brachycephalic breed known to suffer with various health issues because of the abnormally short snout and intense breeding, live the shortest life, with an average life expectancy at birth of just four-and-a-half years.

       The Royal Veterinary College (RVC) analysed data from more than 30,000 dogs in Britain that died between 2016 and mid-2020, and calculated the average life expectancy at birth.

       Done in collaboration with the National Taiwan University, the researchers found that Yorkshire terriers were the second longest-living breed (12.5 years) and border collies were third (12.1 years).

       Other flat-faced breeds – English bulldogs, pugs and American bulldogs – rounded out the bottom four alongside French bulldogs, with none of them expected to live more than eight years at the time of birth.

       The study found that across all breeds, the average life expectancy was 11 years and three months. However, males tend to live four months less than females.

       Neutered dogs also lived longer than intact pets, with it being about a month longer for neutered males and about six months for spayed females.

       The study included data from more than 250 different dog breeds as well as mutts, but there was only enough data for a league table to be created for 18 breeds as well as crossbreeds, which covered roughly half of all the canine study participants.

       Labradors were the most common dog in the study, followed by Jack Russells and cocker spaniels.

       Whilst the average life expectancy for all dogs was 11.23 years at birth, the equation changed after every year lived.

       For example, by the time a dog is four years old, it likely has less than eight years left to live. But at 10 years old this drops to 3.3 years, before falling to less than one year if a pet is 16.

       The researchers also calculated at what point a dog can be expected to only have 18 months left to live and if an English bulldog makes it to nine years old, then it can be expected to see only one, maybe two, Christmases.

       In contrast, longer-lived dogs such as Yorkshire terriers, Jack Russels and mutts don’t reach the 1.5-year end-of-life threshold until the pet is 14 years old.

       Dr Kendy Tzu-yun Teng, the lead author of the study from the National Taiwan University, said: “The dog life tables offer new insights and ways of looking at the life expectancy in pet dogs. They are also strong evidence of compromised health and welfare in short, flat-faced breeds, such as French bulldog and bulldog.”

       Dr Dan O’Neill, the associate professor in companion animal epidemiology at the RVC and a co-author on the paper, added: “The short life expectancies for flat-faced breeds such as French bulldogs, shown by the VetCompass Life tables, supports the UK Brachycephalic Working Group’s call for all owners to ‘Stop and think before buying a flat-faced dog’.”

       The study is published in the journal Scientific Reports.