Generally, in the animal kingdom, size means life. The bigger an animal is, the longer its average lifespan is. Rats in the wild typically live less than a year whereas an elephant outlives darn near everything.
Within the dog community, however, things are different. Small dog breeds like the Chihuahua regularly live deep into their teens while giant breed dogs like the mastiff are lucky to see their 10th birthday, and medium dog breeds are somewhere in between. But why, on average, do small breed dogs live longer than large breed dogs? We’ll answer that question and more, but first let’s find out how long small breed dogs are generally a part of the family.
How Long Do Small Dogs Live?
The average dog lifespan is around 10 to 13 years. Smaller dogs generally exceed the average lifespan, getting closer to 15 years. Of course, size isn’t the only influence on how long a dog lives. A dog’s average lifespan also depends on other factors, like their breed, their genetics, how well they’re cared for (including receiving appropriate nutrition and maintaining a healthy weight) and any health problems they may have.
Everyone wants their dog to live a life as long and as healthy as possible, and a group of researchers at the Dog Aging Project are attempting to learn how to make this a reality. By following the lives of tens of thousands of dogs for 10 years, the researchers hope to identify what biological and environmental factors maximize healthy longevity. An important part of their research is not just to help dogs live longer but to make sure those added years are also healthy years.
Why Do Dogs Age So Fast?
According to Sir Walter Scott, the reason dogs live such short lives is out of “compassion for the human race.” Given how much we suffer at the loss of a dog after about a decade, he surmised, the pain of parting would be that much worse if they were to live any longer.
Profound thoughts aside, one theory why dogs don’t live longer is due to their faster metabolism, growth and development compared to humans. Fun fact: if you’re wondering how old your canine companions are in human years, don’t multiply their age by seven. It’s actually a myth that one human year equals seven dogs years.
Why Do Small Dogs Live Longer Than Large Dogs?
It seems that small dogs may literally “last” longer. In a 2013 research study,1 the scientists concluded that big dogs simply age faster than small dogs. The study reports that large dogs age at an accelerated pace, “as though their adult life unwinds in fast motion.” They may stay in “puppy” mode for a long time — picture that skinny, goofy Great Dane — but when they finally become “adults,” their lives fly by.
The study even puts a number to how fast it can happen, showing that “an increase of 2 kg (4.4 lbs) in average body mass leads to a loss of about 1 month in life expectancy.” The bigger large breeds are as adults, the shorter that time as adults might be.
Another theory is that smaller dogs are around longer because there’s more wear and tear on a large dog’s body. More weight on their joints. More strain in their heart to get the blood to the ends of those long limbs. And large dogs are bigger for a longer amount of time. A Great Dane, for instance, reaches its full height within a year to 18 months of age, while it can take another year for its body to reach full maturity. Basically, they’re large dogs quickly, without all the muscle they’ll eventually need to support that frame.
Some pet parents mistakenly believe that feeding extra food to their large breed puppy is best for the puppy’s development. While large and giant breed puppies have the potential for rapid growth, it really isn’t healthy for their bones and joints. And extra body weight can stress their immature and developing skeleton. When large breed puppies are overfed, they are prone to developing bone and joint problems such as hip dysplasia, osteochondritis dissecans (inflammation of cartilage and bone) or panosteitis (painful inflammation of the outer surface of the long bones in the legs).
Adding another wrinkle to the shorter lifespans of larger dogs is that larger breeds seem to be more susceptible to life-altering health issues. For example, some large breeds are susceptible to gastric dilatation-volvulus which is a life-threatening condition in which the stomach becomes gas-filled, distended and twisted on itself, resulting in an obstruction.
Don’t Give Up on Larger Dog Breeds or Giant Breeds Just Yet
This isn’t to say that if dog owners want a dog to be their companion for double-digit years they must stick to smaller breeds like Pomeranians and dachshunds. Medium breed dogs like Labrador retrievers and Australian shepherds regularly reach age 12 and beyond.
And here’s the thing; dogs seem to live only to defy average lifespan expectations. Painting an entire breed with a single brush is a great way to be proven wrong, and for every Yorkie with small-dog syndrome who careens toward the age of 20, there’s a gray-faced old golden retriever nipping at their heels. Adopt the dog that fits your life and work to make their life as wonderful as they’ll make yours — however long that might be.
Reference
- Cornelia Kraus, Samuel Pavard, and Daniel E. L. Promislow. “The Size–Life Span Trade-Off Decomposed: Why Large Dogs Die Young.” American Naturalist 181, no. 4 (2013): 492–505. https://doi.org/10.1086/669665.
