Most pet parents have likely heard the theory that mixed-breed dogs live longer and are healthier than purebred dogs.

Do mixed-breed dogs live longer?

While there’s some research supporting the theory that some mixed breeds could live longer, it’s not a simple answer.

Dr. Annette Louviere, of Wisdom Panel pet DNA testing service, says that a recent study by the University of California, Davis and Wisdom Panel found that breeds with higher in-breeding require more veterinary care. It also found that after removing brachycephalic breeds from the analysis, larger breeds in this category tend to require even more health care than smaller-sized breeds. And typically, breeds with the lowest amount of in-breeding came from randomly-bred backgrounds (mutts) or breeds with recent cross-breeding (like the Australian Labradoodle).

How Long Do Mixed Breeds Dogs Live?

Dr. Louviere says dog life expectancy can vary depending on the size and breed of the dog. But average dog lifespan for a typical medium-sized dog is thought to range between 10 and 13 years. Dogs with the longest lifespan include smaller breeds, which tend to live longer than large and giant breeds.

Though it’s difficult to predict, says Dr. Louviere, some sources say mixed-breed dogs have an average lifespan of 11 years while others go up to 14 years. She says a variety of factors influence the lifespan of mixed-breed dogs, which is what makes predicting life expectancy difficult. But in-breeding and body size tend to play important roles in dog lifespans.

However, that doesn’t mean mixed breeds will necessarily live longer. For instance, a 2013 study by the University of California, Davis found that 13 of the 24 genetic disorders evaluated in the study were prevalent in about the same number of mixed-breed dogs as purebreds.

Why some dogs have a longer lifespan

There’s a need for more research to learn more about aging and longevity in dogs.

This is the idea behind the Dog Aging Project, a nationwide long-term study of health aging in dogs. It aims to identify the biological and environmental factors influencing healthy longevity. The community science study collects information about each participating dog from the pet parent and their veterinarian, including information about disease history, activity, diet, cognitive function and more. About 40,000 dogs have been enrolled in the study so far.

Daniel Promislow, principal investigator for the Dog Aging Project, was inspired to study aging in dogs by a 2007 article in the journal Science about the genetics of size in dogs. Daniel, who is also a professor in the Department of Lab Medicine and Pathology, and Department of Biology at the University of Washington School of Medicine, says he realized that we could learn a lot by studying aging in dogs, potentially for both dogs and people.

He says during the past year, Dog Aging Project researchers have been analyzing their first year of data.

“We have seen that among the dogs in our study, older dogs are less active. This is not surprising,” he says. “What did surprise us is that older owners have dogs that are more active. As we thought about this finding, we realized it might be due to older owners having more available time, either because they are retired, or simply have more flexible work schedules.”

He says they have also found a strong association between feeding frequency and several diseases, but need more information before they can draw any conclusions from that. They are also now starting to analyze molecular biology data to begin searching for molecular signals of health and disease in dogs.

“We are also looking at how various environmental variables, from air pollution to socio-economic status to nearby parks, are associated with health,” he says.

He says the project and other research has shown that for a given size, mixed-breed dogs tend to live more than a year longer than purebred dogs.

“We are very interested in understanding the underlying biology that influences this large difference in life expectancy between purebred and mixed-breed dogs,” he says.

Improving the average dog’s lifespan

There are many experts, groups and animal lovers interested in finding ways to improve dogs’ lifespans. In fact, The Functional Dog Collaborative aims to support the breeding and raising of purebred, outcrossed and mixed-breed dogs while focusing on physical and behavioral health. They have a private group on Facebook with 10.4K members.

Of course, it all starts with information and education. Dr. Louviere says there are many helpful resources within veterinary communities, breed clubs and reputable online sites where pet parents can find common health issues about their purebred dogs. Wisdom Panel hosts an online breed library that includes information on various genetic health conditions of reported dog breeds.

With the ongoing research on dog longevity, we will soon have more insight into improving the lives of our beloved pets.