A 2019 study from the American Animal Hospital Association shows that, on average, mixed breed dogs live longer than their purebred counterparts. Purebred dogs may have shorter lifespans due to inbreeding. Purebred dogs are bred for specific physical features, but they also pass down genes for illnesses that may reduce their life span.
Because of the variety and scope of differences within the categories of mixed breed and purebred dogs, it may be more helpful to use other metrics to gauge your dog’s life expectancy. There are a lot of different types of breeds within the umbrella categories of “mixed” and “pure” breed dogs. A purebred Bichon and a purebred Great Dane are grouped together under this large umbrella, for example. But these two breeds have greatly different life expectancies.
Breed
Knowing your dog’s breed can give you a wealth of information, one piece being estimated life expectancy. The American Kennel Club’s (AKC) website has profiles of breeds recognized by the AKC with the typical life expectancy of that breed.
The information on the AKC website is particularly valuable for people who own purebred dogs. If you own a common mix, like a goldendoodle or teddy bear (Bichon and Shih Tzu mix), you might be able to find some estimates on their life expectancy. If you don’t know what breed your dog is, there are other factors to consider when thinking about your dog’s life expectancy.
Size
On average, larger dogs are observed to have shorter life expectancies than smaller dogs. Take the Great Dane versus a Bichon: the AKC lists their life expectancies as 7-10 years and 14-15 years, respectively. On the low end of the ranges given by the AKC, Bichons are expected to live twice as long as a Great Dane. This trend holds true when comparing life expectancies of multiple breeds.
Overall Wellness
Like in humans, your dog’s general wellness plays an important part in determining how long they live. Making sure your dog receives all of his vaccinations, gets a nutritious diet, and exercises regularly will all positively affect his lifespan.
Determining how long your dog will live is not an exact science. Further, many of these factors are out of your control. As a pet owner, you can't change your dog’s genetic predispositions, nor can you readily change environmental factors like air quality. The most impactful thing you can do for your pet is to continue to ensure their overall wellness and quality of life.