It once was generally accepted that a dog ages seven years for one calendar year. “It’s not that simple,” according to Pet Loss at Home co-founder, Rob Twyning. “A dog’s first year is more like 15 years’ aging. In a year, you’ve probably noticed they behave somewhat like a human teenager because they are about that age in their bodies.”

The seven year guesstimate likely traces back to 13th century monks at Westminster Abbey. What else did they have to do? They certainly weren’t dog experts. Veterinary science has improved the estimation.

Aging happens faster for bigger dogs

Not all dogs are considered senior citizens at the same age, so it is important to watch for the first signs of aging and take the necessary steps. Larger breeds tend to pass earlier than smaller ones. Vets say a 10-calendar-year-old small dog is about 56 in human years. A large dog is 66. A really big one is 78, aging it 22 years beyond the small home euthanasia

“Smaller dogs can live more than16 years,” says Twyning, but he’s quick to point out that they can outlive that benchmark. “A medium or large size dog’s life expectancy is usually around 10 to 13 years. Giants might make it to 10, but it’s not common. These are things we don’t like to think about, but the point is we have to anticipate that they won’t be around forever as much as we’d love them to be.”

To further complicate things, Twyning says, “There’s also a difference in aging between breeds. Beagles age differently than other dogs the same size. Mastiffs don’t age rapidly at first, but it catches up and surpasses smaller breeds after three years.” What this means is that end-of-life planning may come sooner than you think, depending upon your pet. It also means that you can’t rely on the myth when it comes to spotting signs of aging.

Dog aging signs are similar to human signs

As with humans, advanced years often bring changes in a dog’s physical abilities. Hearing and vision depreciation could be noticeable by seven or eight trips around the sun. Movement might not be as fluid by five or six calendar years. Those are expected signs of any creature getting older.

More serious medical conditions are more common with older adult dogs, too. Cancers, arthritis and other joint problems, digestive troubles, even canine dementia, can crop up long before you expect. A serious injury early in a dog’s life can also reduce the life expectancy and make it more susceptible to earlier aging signs.

To ask more questions, please reach out to Rob Twyning and include your city, state, or ZIP code so we can direct your questions to our local veterinarian team member in 50 metro areas.

Image Susan McCarthy, used with permission.