While pets are nearly perfect, one thing they could improve is their lifespan. Wouldn’t it be great to bring home a dog or cat as a child and have that pet with you for the rest of your life? That question led me to investigate what factors influence how long our pets live—and what we might be able to do to keep them with us just a bit longer. What I found is the subject of this blogpost.

Pet Longevity is Linked to Genes

Unfortunately, many factors that influence a dog’s lifespan are out of our control. Dogs are born with a unique set of genes that help shape their health and longevity. In dogs, longevity is associated with breed and, in general, small breed dogs live longer than large breed dogs.

One notable exception to that rule is the Cavalier King Charles Spaniel. Despite being a toy breed, Cavaliers have an average lifespan of only nine years. In a study looking at Cavies that lived greater than thirteen years, researchers identified a number of genes that might explain why some individuals lived significantly longer than others.

While this information is intriguing, we don’t know enough yet to recommend a breeding strategy dogs based on longevity-related genes to improve the longevity of Cavaliers.

Cancer Shortens Lifespan—But Not Equally Across Species

Cancer is a disease that begins with a single cell going awry, and it clearly shortens lifespan in our human and canine family members.However, this is not true for all species. If you had an elephant family member, for instance, cancer would be far less of a concern.

How can this be? Elephants are enormous and have far more cells in their body than humans or dogs—it seems like they would have more potential for a cell to go wrong, resulting in cancer. Yet, elephants have an average lifespan of 60-70 years and have a much lower cancer rate than people or dogs. What accounts for this difference?

One explanation is evolutionary time. Thanks to advances in human and veterinary healthcare, people and dogs are living much longer today than they were 100 years ago. This sudden increase in longevity has not allowed enough time for cancer-protective mechanisms to evolve in humans and dogs. In contrast, elephants and other long-lived creatures have had millions of years to develop robust cancer defenses that are calibrated to their lifespan. The theory was recently explored in the journal Aging Cancer.

“Moggies” and “Mollies” Live Longer

I found fewer studies on feline longevity than canine longevity, but one recent study found that “mollies” and “moggies” tend to live longer. I confess, I had to look up those words—a mollie is a spayed female cat, and a moggy is British English for a mixed-breed, or what we in the US commonly call a domestic cat.

In the United Kingdom, the average lifespan of a cat was roughly twelve years. Mollies lived the longest, and moggies lived longer than purebred cats. Across multiple studies, spayed and neutered cats consistently live longer than those not spayed or neutered.

Pet Longevity is Linked to Body Weight

Every veterinarian cares for some pets who seem to defy the odds when it comes to lifespan, and we often wonder what sets them apart. One recent study of Labrador retrievers compared those with a normal lifespan (between nine and thirteen years) to those with exceptionally long lifespans (greater than fifteen and a half years).

These researchers found no difference in lifespan between female and male Labradors, and age at neutering did not impact longevity. The key difference was body composition. Dogs with exceptional longevity had less body fat and more lean muscle.

Since this study only involved a single breed, we need to be cautious about generalizing this information to all dog breeds. Still, keeping your dog at a healthy weight is a good plan even if your dog is not a Labrador.

What Can Pet Owners Do to Improve Longevity in Dogs and Cats?

While the studies mentioned above are interesting, the advice I can give to pet owners is not new:

Keep your pet at an idea body weight.

Spay and neuter your cats.

By following these steps, you will have taken the most important steps to keep them around as healthy members of your family for as long as possible.