For a dog, it’s good to be small and have a long nose.
In the United Kingdom, breeds matching that description, such as miniature dachshunds and some terriers, can expect to have the longest lives, researchers report February 1 in Scientific Reports. Medium and large flat-nosed dogs like bulldogs or mastiffs, on the other hand, tend to have the shortest lives.
On average, canine companions around the world can expect to live roughly 10 to 14 years. Life span varies among breeds, and some studies show that small dogs tend to live longer than large dogs. But myriad factors such as genetic history and body type could also influence life expectancy.
“This paper is only just scratching the surface of this problem because it’s so complex,” says data scientist Kirsten McMillan of Dogs Trust, a dog welfare charity headquartered in London.
To explore how body and head size might influence canine life spans, McMillan and colleagues collected data on individual dogs across 18 different U.K. sources such as breed registries and veterinarians. Out of more than 580,000 records, about 284,000 dogs had died. The analysis included more than 150 pure breeds as well as crossbreeds.
Of purebred breeds, small dogs with long noses had the longest median life expectancy of 13.3 years. Miniature dachshunds, for instance, live around 14 years. But bulldogs, a medium, flat-faced breed, tend to live less than 10 years. Popular dogs such as border collies and Labrador retrievers — the most common dog in the dataset — have life expectancies of around 13 years.
But face shape is only part of the story, McMillan says, because some flat-faced dogs tend to be longer-lived. Tibetan mastiffs, for example, live to be around 13 years old. “We can see that there’s an increased risk [of early death in some flat-faced dogs], but there’s something else going on there.”
The findings are indicative of life expectancy only for dogs living in the United Kingdom, McMillan says. Still, other researchers could use similar methods to investigate dog life spans in their own countries. “Once we have those estimates from country to country,” McMillan says, “that can be hugely helpful in us working towards improving the longevity of some of these [breeds].”