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when muzzles go gray: the life stages of dogs



Yesterday, we talked about how confusing some of the information around measuring cat life stages can be. For dogs, the assumptions are even less substantiated.  The average lifespan of a dog is very dependent on its breed, and as a general rule, small breed dogs live longer than large and giant breed dogs. 

You are probably familiar with the saying that one year for humans is equivalent to seven “dog years.” But this adage is inaccurate, because a 10-year-old Chihuahua is very different than a 10 year old Irish Wolfhound. According to typical breed life expectancy, the Chihuahua likely has five or more years to live, while the Wolfhound has already exceeded expected life span for his breed. 

The American Animal Hospital Association Canine Life stage guidelines suggest using expected breed life span to calculate the correlation to the various life stages of humans, so a dog’s true age would look something like this:

Stage                     Definition

Puppy                   Neonate until reproductive maturity

Junior                    Reproductively mature, still growing

Adult                     Finished growing, structurally and socially mature

Mature                 From middle up to approximately the last 25% of expected lifespan (a window of time around half of the life expectancy for breed)

Senior                   From maturity to life expectancy (approximately the last 25% of the expected lifespan)

Geriatric               At life expectancy and beyond

From these suggested definitions, you can estimate a dog’s age in human years if you assume that a person lives to 100 years of age.  For example, our 10-year-old Chihuahua is in the middle to approximately the last 25% of his expected lifespan, and so would be considered “mature,” putting him at 50-75 human years old. However, our 10-year-old Irish Wolfhound is at an age beyond his life expectancy so is considered to be “geriatric,” which translates to 100 human years or older.

Determining the age of a dog or cat in terms of human years is fun, but ultimately inaccurate.  And what is most important isn’t the physical age of a pet, but how active and healthy they are (which why we measure their physiological and metabolic age).

The bottom line is, if you want your pet to live a happy, healthy life, feed him the best diet, make sure he gets plenty of exercise, give him regular vet care, get pet insurance in case he ever gets sick or injured, and follow your vet’s recommendations for keeping him in optimal health. Do all of this, and you’ll set your pet up for a lifetime of good health and happiness – at any age.

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Chris AshtonCo-Founder and Co-CEO of Petplan Pet Insurance
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