Aging in Dogs - Aging Profile

Aging Profile

They can be summarized into three types:

• Popular myth — It is popularly believed that "1 human year equals 7 dog years" or the like. This is inaccurate on two scores, since the first year or two years represent some 18–25 years, and the ratio varies with size and breed.
• One size fits all — Another commonly used system suggests that the first two years equal 10.5 years each, with subsequent years equaling four human years. This is more accurate but still fails to allow for size/breed, which is a significant factor.
• Size/breed specific calculators — These try to factor in the size or breed as well. These are the most accurate types. They typically work either by expected adult weight or by categorizing the dog as "small", "medium", or "large".

No one formula for dog-to-human age conversion is scientifically agreed on, although within fairly close limits they show great similarities.

As a rough approximation, the human equivalent of a one-year-old dog is between about 10 and 15 years—a one-year-old dog or cat has generally reached its full growth and is sexually mature, although it might still be lanky and need to fill in a more mature musculature, similar to human teenagers. The second year is equivalent to about another 3 to 8 years in terms of physical and mental maturity, and each year thereafter is equivalent to only about 10 or 11 human years.

Emotional maturity occurs, as with humans, over an extended period of time and in stages. As in other areas, development of giant breeds is slightly delayed compared to other breeds, and, as with humans, there is a difference between adulthood and full maturity (compare humans age 20 and age 40 for example). In all but large breeds, sociosexual interest arises around 6–9 months, becoming emotionally adult around 15–18 months and fully mature around 3–4 years, although as with humans learning and refinement continue thereafter.

According to the UC Davis Book of Dogs, small-breed dogs (such as small terriers) become geriatric at about 11 years; medium-breed dogs (such as larger spaniels) at 10 years; large-breed dogs (such as German Shepherd Dogs) at 8 years; and giant-breed dogs (such as Great Danes) at 7 years.