There is a myth that goes around the world that, one year in the life of a human is strictly equivalent to, seven years of a dog’s life. It sounds educated and simple, but this rule of thumb is more often inaccurate. The reality is much more complicated. The first eighteen months chronologically of a dog’s life, are approximately the first eighteen years in human maturity. That’s more like a 12 to 1 ratio.
Dog life expectancy is tied to several factors; Breed type, weight, diet, exercise and physical stature. On the average, small dogs live the longest and age the slowest. Large dog’s age faster and usually are the first to go to the great dog park in the sky.
A major factor is weight and anatomy. A Great Dane has more weight and volume than a Yorkshire Terrier, so its cardiovascular system must work harder. This leads to heart problems that are more severe and occur earlier.
A study of 250 dogs indicates that, seven dog years per human year is not valid.
The first chronological year in a dog’s life approximates twelve years of a human’s life. When a dog is about three and a half years chronologically aged, it is equivalent of a 30 year old person.
After three years (see chart above), the curves diverge from each other. The graph indicates that dogs greater than 90Ibs age at a rate of 7.8 years of life for every chronological year. Dogs between 21-90lbs age at the rate between 5.2 and 5.5 years/year. The dogs that are below 21lbs tend, to age at the slowest statistical rate (4.7Human yr/Dog yr).
Life expectancy can be improved my exercise and proper nutrition.