Which dog has the longest life expectancy

Small dogs, such as Chihuahuas and Pomeranians, have a relatively long life expectancy. The average life expectancy of a small dog is fifteen to eighteen years, that of a medium-sized dog is about fifteen years and that of a large dog is about ten years. The lifespan of a dog has a lot to do with the way it is raised. Generally dogs that are domesticated, have a more balanced diet and get the right amount of exercise will live longer than stray dogs and dogs that have been eating heavy salt for a long time.