http://www.straightdope.com/classics/a2_010b.html
I wonder if the same basic formula applies to cats. My 19 year old cat certainly does not act like she’s 97, more like upper middle age. The vet at the cat hospital told me that these days it is not uncommon for cats to live into their high teens. Do cats generally have a longer life expectancy than dogs?
I must take issue with this bit of the article:
Wrong, wrong, wrong. Well, ok, not entirely, but a wee bit inaccurate. 
Canines reach sexual maturity within about one year of birth, true. But humans do the same by about age 13 or so, not 21. The difference is we don’t stop growing until somewhere between the ages of 17 and 22 (according to most sources), while the dog normally attains its full size at about the same time as it sexually matures.
>Do cats generally have a longer life expectancy than dogs?
Yes.
Hi everyone – I just joined this message board specifically to comment on this article.
As most owners of dogs know, smaller dogs, or what I typically call “little yappy dogs” (Bichon Frise, toy poodles) consistently live longer than larger breeds. If your yellow lab lives to 15, it’s a pretty big deal, but lots of little dogs live that long. If a Great Dane lives to eight, he’s had a full life. I definitely buy the idea that there’s one rate of “chronological” aging while a puppy (which may be somewhat longer than a year in my opinion), and a different rate of “chronological” aging once fully grown, but I don’t think it’s that simple. Or is it simply that smaller dogs are plagued with fewer health problems? Do Great Danes simply have the life expectancy of a third-world country? :dubious:
What exactly are you taking issue with? Do you believe that a dog’s age should only be compared to the human age scale by sexual maturity only, not by physical maturity?
The fact that a dog reaches both areas of maturity at approximately the same time shouldn’t matter. Based on the column’s info, we’d call a one-year old dog an “adult”. However, we don’t call a 13-year old human - despite being sexually mature - an adult, because he’s not yet physically mature.
Anyhoo…
Medicine often does. Check OTC pharmaceuticals. They typically in the US have the same dose for anyone 12 years or older. And in many parts of the world, adulthood is considered to happen when a person reaches sexual maturity.
Correct. In the USA, adulthood is legislated
Anyway, to stay on topic…
I was in a play when I was in high school. The play was somewhat of a spoof on “Bonanza”. At one point in the play, the “Ben Cartwright” character calls his dog over and starts feeding him. While feeding, “Ben” addresses the audience: “You know, this dog is seventeen years old. That’s four thousand years for you and me!”
I just happened to see a chart on the wall at the vet’s office this morning. (It was from Purina Veterinary, but I can’t find it on their site at the moment to try and provide accurate cites)
It labeled in a way to make me believe the “conversion” of critter years to human years is the same for cats and dogs. The difference is in weight and size. There was no distinction made for species.
As **doogie ** said, the first range is small breeds, up to 20 pounds. By critter age 19, the human equivalent was in the neighborhood of 146 years. The chart scale ended at 19 or 20 years.
Big breeds top out at around 13 years, with a human equivalence of about 98 years.
Medium sizes max out at 15-16 years, with a human equivalent of around 120-130 years. (This is from memory - I was waiting for a fair while in that exam room with nothing else to read!)
For all sizes, by the end of the first two years, your critter is around 20 human years, give or take a couple.
Hopefully, CrazyCatLady, or anyone else here that works at a vet’s office will have this chart handy to explain it better than my memory can.
I’m really surprised that Cecil didn’t go into more accurate details as I’m sure it’s documented at professional levels. At the very least, the difference between small and large dogs. Life expectancy and aging is different in these groups and you can’t sum it up in one equation for all dog breeds.
I too have seen this age chart related to breed sizes and it’s a much more realistic comparison to human aging.
Maturity does not happen at one year of age in dogs. If you assume that adulthood is marked by the end of growth, most dogs reach this stage of maturing at 18months to 2 years of age. Small dogs maturing earlier than large.
Any large breed owner will vouch to the fact that their dogs aren’t fully grown at one year of age. Vets even recommend that you continue feeding puppy or growth formulas until 18 to 24 months of age in large breeds.
You then have exceptions to life expectancy with certain breeds like the british bulldog and the great dane. Large dogs have a life expectancy of about 10-12 years whereas these two particular breeds it’s 8-10 years.
TarantulaGirl
Junior the Wonderdog, our 110lb labrador, was 17 people years old when we helped him over the Rainbow Bridge a couple of months ago. Our vet stopped converting his age for us once he was the equivilant of 140+ people years old :eek: That was several years ago. At the time of Juniors death, he was the oldest labrador ever treated by our vets office and was quite the celebrity since he’d been going to the same office since he was a pup.
W.C. the Cat was Juniors best friend and faithful companion until her death a year ago. Her death was not due to old age (16 people years old) but an unfortunate encounter with a car 
Both critters demonstrated arthritis in their last years, but not seriously enough to hamper their ability to eat, frolic, and take care of business.
I miss them both
Thanks, everyone, I knew there had to be more to it than Cecil’s simplified description, though admittedly, his is better than “one dog year equals seven people years.”
I just thought I’d add that, on my 25th birthday, I recieved a poorly-spelled birthday card from Arfer T. Bowser, my mom’s faithful companion. Inside, he had written "Wow, are you really 175 years old???
This and this confirm that I wasn’t that far off from estimating my cat’s age in the OP afterall. Its pretty much the same as a dog’s, except that a cat is about 24 in human age at the age of 2. After that the same rule of 4s applies. Here’s a dog year calculator.
From this data, can one assume that a dog and a cat receiving the same level of care have about the same life expectancy, give or take a year or two?
I’d like to know where Cecil got his math? A year is a year, period, as defined by humans. Trouble is, I don’t think dogs define periods of time, so one year to dogs is one year to humans----to humans. Now what I think Cecil, and this thread, might be trying to say is: dogs physically mature and physically degrade (or age) at a factor of 9x4+21 years greater than humans (assuming the math is at least fairly accurate).
Medical dosing indicates sexual and mental maturity? HUH!? Actually, it probably more accurately indicates a body weight and organ developmental maturity suitable for adult dosing. Nothing to do with sexual maturity or the mental capacity of an individual to behave as an adult. None of the factors in Young’s rule or Clark’s rule represent emotional or sexual variances. Pretty much age, weight and a few derived constants.
For my dad’s 52nd birthday recently, my brother and I got him this card:
Front: “In dog years…”
Inside: “You’re dead!”
Looks like it from this data, although it also seems to be true that more cats live into their late teens than dogs do. And then there’s the issue of larger dog breeds, which that dog year calculator didn’t address.
And it seems odd to me that small dogs would live longer than large ones…I seem to remember reading somewhere that larger animals (which by virtue of their size have slower metabolisms) tend to live longer than smaller ones–humans > cats and dogs > mice > fruit flies. If anybody has knowledge or a cite to the contrary, though, I’d be happy to hear it.
It’s always been explained to me that it’s due to the fact that modern dog breeds aren’t natural. Most critters evolve to have an anatomy that fits the expected normal size range for the species. Big dog breeds have been artificially pushed past that limit. Basically, as I understand it, their poor little hearts don’t get bigger proportionally as the body size increases (this site may be relevant here). Thus, the heart (and I assume other organs) have to work harder and wear out faster.
I understand that the life expectancy for super-tall/super large humans is also lower than “average”.
On the other hand, a lab, say, is a lot closer to wolf-sized than is a chihuahua. And how long do wolves live? It seems to me that it’s not so much a matter of large (normal-sized) breeds having unnaturally short lives, but that small breeds have unnaturally long lives.
Okay, fair enough. I suppose the end effect is the same. Heart works harder and gives out sooner.
Alternatively, perhaps there is some uninvestigated health benefit to constant exposure to high-pitched “yippy” barking.