We've all heard the old saw that each dog year is the equivalent of seven human years. The reality is more complicated than that. Years in a dog’s life correspond more accurately to phases of human life -- baby, teen, young adult, middle age, geriatric. The ASPCA suggests that the first two years of a dog's life roughly cover the phases that humans cover from birth through the teen years. After that, most dogs age about four years for every one human year. However, there is more to consider in estimating your dog’s physical age and likely lifespan.
Identify your dog’s breed. This isn't always an easy thing to do, especially if you have what's lovingly called a mutt, or mixed breed. Start by asking anyone who might know -- a previous owner, the shelter, a veterinarian or someone else who knows dogs well.
Research information about the breed or breed mix of your dog. In general, smaller breeds have longer lifespans than larger breeds. Mixed breeds as a whole live longer than purebred dogs.
Consider your dog's gender, particularly if the dog hasn't been spayed or neutered. Gender, hormones and pregnancies all may affect longevity. Female dogs tend to live longer than males do.
Ask your veterinarian or dog breeder about hereditary problems in the breed. If you dog develops one of these genetically transmitted problems, it could greatly affect his potential longevity. For example, some giant dog breeds, such as Great Danes, are prone to heart ailments. Brachycephalic dogs with short snouts, such as pugs and bulldogs, often have breathing problems that require surgery and make them prone to heat stroke. Review the research on your dog's breed or component breeds to prepare for possible problems in the future.
Take your dog to a veterinarian for a physical examination as soon as possible after adopting her. This will help to establish a baseline for evaluating future illnesses or events that may affect her lifespan.
Consider that not all dogs, even of the same breed, will age at the same rate when they are treated differently. A healthy dog fed a good diet and offered good housing, companionship, engaging activities and exercise usually ages better and lives longer than a neglected or ill-treated dog.
Allow that an individual dog may suffer correspondingly more disorders than may be typical of the breed in general. If your dog suffers from diabetes, a heart disease or other vital organ condition, thyroid disease or any other major health problem, chances are he won't live as long as most members of his breed. TLC goes a long way, but Mother Nature always has the last word.
No matter your dog's breed, gender or health, respect and kindness go a long way in keeping your beloved pet with you as long as possible.
- Dog and Puppy image by Philip Date from Fotolia.com