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Written by leading veterinarians to provide you with the information you need to care for your pets.

The Daily Vet by petMD

The Daily Vet is a blog featuring veterinarians from all walks of life. Every week they will tackle entertaining, interesting, and sometimes difficult topics in the world of animal medicine – all in the hopes that their unique insights and personal experiences will help you to understand your pets.

From Dog Years to Pig Years: How Animals Age Compared to Humans

The process of aging has been on my mind recently. My pets (two cats and a dog) are all at least a decade old and are starting to show their years. Also, a colleague of mine posted on Facebook a while ago that she saw her oldest patient yet: 75 years old and still doing great. Speculation then ensued, with guesses as to what animal she was treating (it was a tortoise — she recently completed a residency in zoo medicine).

These things got me thinking about my oldest patients and how animals age. Most people have heard the axiom that one dog year is equivalent to seven human years. While I’m not sure what scientific basis this has, I begrudgingly admit it’s fairly close.

A 5-year-old dog is usually in the prime of his life (as a 35-year-old person usually is); a 1-year-old dog has the discipline and attention span of a fruit fly (as does a 1-year-old child); and a 10-year-old dog is generally slower, calmer, and wiser (as are some, but not all, 70-year-old people). Of course this depends somewhat on the breed of the dog and its overall health, but in general, the rule seems to fit.

Occasionally people will ask me to relate horse years to human years. This one is harder for me to extrapolate. My first horse, a gray Connemara pony named Wimpy, was 25 years old when I got him and he was going strong for the period of time I had him. I know horses well into their 30s that still go for trail rides and are cranky and full of beans if they are left out of the action.

I’ve read speculations that perhaps one horse year is equal to three human years, at least until sexual maturation and growth has finished, and then the equivalence is more like one horse year to five or six human years. Searching for this information, I am instead inundated with papers on how to accurately determine a horse’s age by his teeth. I am left wondering why there hasn’t been much research into this topic.

Rarely, people will ask about cow years. Usually, cows are hamburger before they turn too old (sorry to be so blunt, but it’s true), so determining how long a cow could live is challenging in this country. I’ve known much-loved cows as old as 14 years (one was named Katie), but I suspect they could live longer than that.

Pigs, creepily enough, can live quite long. The domesticated production pig situation is the same as the cow situation mentioned above, but pot-bellied pigs kept as pets are known to live forever… or a few decades, but it seems like forever when you’re as suspicious and unnerved by their remarkable intelligence and shifty-looking eyes as I am.

One thing that I have noticed that seems common in all species of elderly animals is that their owners care about them in a very profound and endearing way. Just think about your own geriatric pets — don’t you break the rules for them? My own dog, Shadow, now has her own personal water bowl in our bedroom for when she gets thirsty at night. My parents’ 14-year-old cat, Chloe, is lifted to her breakfast bowl on the counter every morning — her own personal elevator. And why not? If one dog year is seven human years, shouldn’t we cherish the time we have with our animals even more?

Dr. Anna O’Brien

Image: Vjeran Pavic / Flickr

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