You watch your young pup bounce across the lawn. You see your old dog lumber slowly to the food bowl. You take a brisk run with your young dog close at your heels. You slowly walk to the mailbox, and your old dog still lags behind. What a difference a few years makes to your dog. You do not feel older, so why does your dog? It may be because what you and your dog consider “old” are vastly different.
How can I calculate my dog’s age?
The most common theory comparing human and canine ages uses this equation:
A dog’s age (in years) x 7 = Age in “dog years”
For example, if your dog was born 7 years ago, he is 49 years old in “dog years.” Or, stated differently, a 7-year-old dog is at a similar stage of aging to that of a 49-year-old human.
This equation is only a rough estimate. A dog’s rate of development skews the age calculation. Dogs develop more quickly in the first two years of life, after which development slows down. During the first two years, one dog year equals about 10.5 human years, so the dog to human aging ratio is 10.5:1 rather than 7:1. At 3 years old, a dog ages 4 years to every 1 human year, making the ratio 4:1 for these years. Using these ratios, a 10-year-old dog is the equivalent of a 53-year-old human. Using the simple 7:1 ratio, this same 10-year-old dog would be the equivalent of a 70-year-old human.
Size and Breed
A more accurate calculation takes into consideration the dog’s size and breed. This method categorizes dogs as small, medium, or large, or uses their estimated adult weight. Smaller dogs age more slowly and have longer life spans. Larger dogs age more quickly and have shorter life spans. In addition, certain breeds live longer than others. When comparing size, small poodles live longer than huge Great Danes. But when comparing breeds, Great Danes may outlive bulldogs, which are larger.
Emotional Aging
To further complicate things, emotional maturity doesn’t always align with physical maturity. Emotional development occurs over time. A 21-year-old human may still be maturing emotionally, and the same applies to dogs. Even though a 9-month-old pup may be socially and sexually active, full maturity is not achieved until age 3 or 4. That is why 2-year-old Labradors still chew your favorite slippers.
In short, there is no definitive answer. There are too many breeds, too many sizes, and too much developmental variability to accurately calculate a dog’s age in human years. What is consistent is the fact that dogs age more rapidly than their humans. A 1-year-old dog often resembles a gangly teenager. A 4-year-old dog has the energy of a young adult, while a 9-year-old dog may walk with the stiff gait of a senior citizen.
What is considered old for a dog?
In humans, some people consider 55-year-olds to be senior citizens. Others delay imposing that status until 65 years. Canine senior status varies, too. Small dogs are considered senior citizens when they reach 11 to 12 years of age; medium-sized dogs become seniors at 10 years of age; larger dogs are seniors a 8 years of age; and giant breeds are seniors around 7 years old. A Great Dane becomes a senior far earlier than a Pomeranian.
Like humans, dogs suffer the effects of aging. Signs you may notice include:
- Loss of vision
- Loss of hearing
- Weight gain
- Loss of energy
- Arthritis and other joint problems
- Loss of muscle tone
- Loss of teeth
- Loss of organ integrity (heart, liver, kidneys)
- Loss of skin elasticity
- Loss of hair
- Loss of immunity
- Loss of mental acuity
Talk to your veterinarian about how you can help your dog through each step of their aging process.
