Wondering how many precious years you’ll be able to spend with your pet pooch? The answer may be in your dog’s size, sex and snout.

Dog breeds that are larger in size or that have flatter faces had shorter average lifespans than breeds that are smaller or have longer noses, according to a study published Thursday in the Scientific Reports journal. Researchers also found that that female dogs lived longer than male dogs. 

MORE: Meet Phantom, Adventure Aquarium’s new giant Pacific octopus

The study looked at data from more than 584,000 dogs across the United Kingdom, collected through breed registries, pet insurance companies, veterinary companies and other sources. The study mostly consisted of purebred dogs, representing 155 breeds, while mixed-breed dogs were combined into one crossbred category.

While researchers found the median lifespan of all the breeds to be 12.5 years, the average lifespan varied greatly between breeds. The Lancashire Heeler had the longest average lifespan of any breed in the study at 15.4 years, while the massive Caucasian Shepherd Dog had an average lifespan of just 5.4 years. 

Other breeds with long average lifespans included Shiba Inu (14.6), poodle (14), Italian greyhound (14) and miniature dachshund (14). Among the breeds with the shortest average lifespans were the Bernese mountain dog (10.1), bulldog (9.8), and Saint Bernard (9.3). The squished-nosed French bulldog — which was named the most popular dog in the U.S. last year — also had an average lifespan of just 9.8 years, according to the study.

“A medium-sized, flat-faced male like a bulldog is three times more likely to live a shorter life than a small-sized, long-faced female, like a miniature dachshund or an Italian greyhound,” Kirsten McMillan, lead author of the study, told CNN.

There were some exceptions to the rule, though, as the Lhasa Apso had one of the highest average lifespans (14) despite its smushed nose. 

Reasons for differing lifespans among breeds could be due to health problems faced by certain breeds. For example, flat-nosed dogs like Frenchies, pugs and bulldogs are predisposed to numerous health issues, including breathing problems, skin infections and eye issues. 

Contradictory to previous research, the new study also found that overall, purebred dogs had longer average lifespans than crossbred dogs. Experts say this could be due to the fact that all mixed-breed dogs were combined into a single category, regardless of size or the breeds that were mixed.

The study isn’t fully comprehensive, as it only involved British dogs and didn’t take into account the dogs’ cause of death, which often may be euthanasia. Overall, though, experts say the latest study opens the door for further research.

“Now that we have identified these populations that are at risk of early death, we can start looking into why that is,” McMillan told the New York Times. “This provides an opportunity for us to improve the lives of our dogs.”