The longevity of a dog's life largely depends on a variety of factors, with breeding and genetics being two of the most important. On average, the lifespan of a dog is 11 to 12 years.

Multiple factors determine the longevity of a dog, including breed, size and the overall health of the pet throughout its life. Taking good care of a dog is one way to allow it to live its life expectancy to the fullest.

Average Life Expectancy by Breed
While there is no specific answer to the question "how long does a dog live," averages are available for all well-known breeds, notes PetMD. For example, bulldogs live an average of six years, German shepherds live an average of 10 years and pugs average 11 years of age. Golden retrievers and bichon frises average 12 years of age, and dachshunds reach an average of 13 years. Studies have shown that smaller dogs live significantly longer than larger breeds even though the cause of this is not known. It is speculated that the quick growth of larger dogs from puppies to adults may increase the likelihood of abnormal cell growth and an increase in the possibility of cancer, notes Forbes magazine.

When it comes to mixed breeds, owners need to take into account the individual weight of the dog as well as the breeds of its parents to determine its life expectancy. Dogs that weigh more than 90 pounds live for up to 8 years, whereas those up to 20 pounds live around 11 years, as noted in the 2013 Banfield State of Pet Health Report. Besides weight and breed, there are multiple other lifestyle factors that may influence the number of years a dog can live.

Dog Longevity and Lifestyle
Just like in the case of humans, the lifestyle of a dog has a significant impact on its well-being as well as its longevity. Keeping a dog at the correct weight and taking it to routine health checks is a way to maintain its health. Owners should also give their dogs the correct amount of exercise for their sizes and ages. Moreover, owners should minimize the chance of their pets getting into an accident by securing them in their vehicles with a doggy seat belt or a dog crate. Scheduling vet appointments as soon as any unusual symptoms appear is another way to prevent untimely deaths. Dog owners should also restrict the pet's access to any kind of harmful substances and toxins.

The Impact of Obesity on Dogs
With approximately 34 percent of dogs in the United States being overweight or obese, it is important to focus on the weight of a pet regularly to avoid complications caused by overnutrition. By keeping a dog at the correct weight for its breed, size and age, owners can reduce the risk of heart and respiratory conditions, diabetes and spine problems. Being overweight is stressful for a dog's musculoskeletal system, which may result in intervertebral disc disease and osteoarthritis. By keeping their dogs fit and healthy, owners can give them the chance to live out their complete life expectancy.