How do I Calculate Canine Years?

by Betty Lewis
    Four or 34? Either way, he's still in his prime.

    Four or 34? Either way, he's still in his prime.

    Brand X Pictures/Brand X Pictures/Getty Images

    The old saying goes even a broken clock is right twice a day. If you're going by the premise that one dog year equals seven human years, the broken clock is right more than you are. Once in Pal's life that might be right, but exactly when depends on his size and breed.

    Dogs age at a faster rate than their human friends. Think about Pal during his puppy months: he packed a load of growing in during that formative first year. On the average, a dog will age to the level of a 15-year-old human during his first year. At 1 year old, you might have been standing and taking your first tentative steps. By Pal's first birthday he should have an understanding of basic commands, is sexually mature and may be transitioning from puppy food to adult food, depending on his breed.

    If Pal's a Chihuahua, he's more apt to live well into his teens; if he's a large dog, such as an Irish wolfhound, his life expectancy is about half as long. Smaller dogs not only live longer as a rule, they also mature quicker in their first few years of life. Large dogs mature slower, yet reach senior status at a younger age, often around 5. Small and toy dog breeds aren't considered geriatric until they're around 10 years old. Medium-sized breeds are usually around 7 or 8 before they're considered seniors.

    Whether Pal's small, medium or large, you can figure by the time he celebrates his second birthday, you're living with a 24-year-old guy. After his second birthday, his growth rate will vary according to size. Small dogs age four years per year after two; medium dogs generally gain five years for every birthday beyond two; large dogs age six years for every human year. If Pal's a 6-year-old Chihuahua, he's about 40 in human years; if he's a golden retriever, he's closer to 45 in human years. All age calculations and charts are guidelines; Pal's health and "age" depend on his diet, exercise and general physical condition.

    If you don't know Pal's birthday and want to get an idea of his age, a good exam can provide clues. Teeth are a great indicator of age. Puppies have their permanent teeth by the time they're 7 months old. If Pal has a full set of beautiful white chompers, he's probably about a year old. Slight yellowing on the back teeth begins around age 1 or 2, and tartar starts building up around 3 to 5 years of age. If Pal's teeth are worn or missing, he's probably in his senior years, when teeth show the effects of age. Cloudy eyes, graying hair around the muzzle, face, head and body, and stiffness also indicate senior status. Younger dogs have more muscle definition than older dogs, who tend to be either bony or chubby, depending on their activity level.

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    About the Author

    Betty Lewis is a writer and editor specializing in pet care, animals, careers and emergency management. She previously ran an animal shelter, where she also served as a kennel attendant and dog trainer. Lewis holds a bachelor's degree in journalism, an M.B.A. and a master's degree in professional studies.

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