One human year does not equal seven dog years.

This is a myth that you can equate people vs dog years on a 1 to 7 basis.
There is no specific formula for dog to human age conversions. A dog’s lifespan is only a fraction of the human’s lifespan, which means that a dog ages more quickly in the same amount of time.

There is no Dog to Human Years formula set in stone. There are too many variables that play a role in determining the aging in dogs. Aging varies a great deal depending on the size and breed of the dog.

Some dog breeds have an average lifespan that is almost double other breeds. Below are some of the main factors that play a role in determining the longevity of a dog:

1. Size –   It is a fact that small dogs tend to live longer. Sometimes up to 1.5 times longer. The smaller the dog and the lighter in weight, the longer the lifespan.

2. Breed –   The breed of a dog will give you an indication of the life expectancy. Apply the “Small Dog Rule” while remembering that there are exceptions to every rule. Large breeds generally have a shorter lifespan than smaller breeds. Weight and muscle mass play a role in determining the longevity of the dog.

3. Gender -  On average, depending on the breed, females will live one to two years longer than males of the same breed. This is similar to the human statistics.

4. Life Style and Health Care -  As a general rule, dogs properly cared for – quality food, regular exercise and medical attention – will live longer. Neutering and spaying will add years to a dog’s life. This is partially due to a reduced cancer risk that is associated with sexual organs.

The most common visible signs of aging in dogs are very similar to their human companions. The first thing you will notice is the appearance of gray hairs around the muzzle and eyes. As your friend begins to age, the following issues start to appear:

- Loss of Hearing
- Loss of Vision – cataracts
- Reduced Energy, deceased activity, sleeping more
- Weight Gain
- Arthritis and other joint problems
- Loss of Teeth

Several larger dog breeds are prone to joint problems, also called hip dysplasia. This can greatly reduce the quality of life of your companion.

Generally speaking, based on the breed and according to their adult size:

- Small Dogs can live over 15 – 16 years
- Medium to larger size dogs often live ten to 13 years
- Giant breeds, such as Mastiffs and Great Danes often only live to eight years

The Guinness World Records show the most recent record for the oldest dog was held by Butch a 28 year old from America who died in 2003. The oldest ever dog was Bluey, a sheepdog from Australia who lived to 29.

Chanel, the oldest Living Dog just turned 21 years old on May 6, 2009. Guinness World Records representatives presented Chanel and her owners with an updated certificate at her birthday party.

Chanel has a challenger. Max, a terrier-cross is now awaiting recognition from Guinness World Records as the oldest living dog. According to his owners, Max has veterinary papers to prove he was born in 1983, which makes Max 26 years young! That would make Max well over 100 in human years!