Which Dogs Live Longer, Big or Small Dogs?

Size is an important factor among many that determine a dog breed's average life expectancy. In general, smaller breeds of dogs tend to live longer, in some cases a lot longer, than their cousins who stand taller and sturdier.

  1. A Look at Life Expectency

    • It's a relatively well-known fact that small dogs live longer than big dogs. Compare one of the smallest with one of the largest: According to the Dog Breed Info Center website, the life expectancy of a Chihuahua is approximately 15 years, while that of a Great Dane is less than 10 years. But specimens within breeds defy these norms. A Great Dane in excellent health, with no stress and a loving environment, can outlive an average Chihuahua whose physical and emotional needs are not met, for instance. Individual dogs' circumstances do shape life span but, in general, big dogs tend to cross over to doggy heaven sooner than do little dogs.

    Size Does Matter

    • According to Dr. Mark Stickney, director of General Surgery Services at Texas A&M University College of Veterinary Medicine and Biomedical Sciences, "Generally speaking, the larger your dog is, the less time it will live." An estimated 40 percent of small-breed dogs live to see their 10 birthday and more. But for the giant breeds, a mere 13 percent live a decade. WebMD reports that an healthy 50-pound dog may live 10 to 12 years in good health while a giant dog like the Scottish deerhound or Irish Wolfhound is considered geriatric at 6 years of age.

    Anatomically Speaking

    • The discrepancy between longevity of small dogs and that of large dogs comes down to internal organs. A Great Dane, which weighs 60 times as much as the Chihuahua, has a heart not vastly larger than the Chihuahua's. Yet the Dane's heart is circulating much more blood through the body. It has to work much harder and gives out sooner. The larger dog's musculoskeletal system is also overtaxed. Though it does grow with the dog, it's supporting a much heavier load. Other factors include hormones, stress, metabolic rates and genetics. Big picture, the large dog's system is working much harder to sustain life than the small dog's is.

    Sizes in All Ages

    • It's not a given that your beloved gentle giant will live only 8, 10, or 13 years based on breed averages. With tender loving care, good nutrition and annual veterinary visits, your German shepherd could outlive your neighbor's Pomeranian. The Guinness Book of World Records named Bluey, an Australian cattle dog, the oldest dog that ever lived when he died at age 29 in 1939. Not bad for a 35-pound dog who statistically speaking should have died when he was between 12 and 15 years old. In 2011, Guinness called a medium-size mixed-breed in Japan named Pusuke the oldest living dog in recent history when he died at the age of 26.