Dan sends me a more accurate calculation.
Dear Dan and I recently had an email ‘conversation’ about the conversion of dog years to human years. Then, yesterday, as in Thursday, he sent me the following article from ZME Science.
Enjoy!
ooOOoo
Here’s a better way to calculate dog years – backed by science.
Lets’s face it, 1 for 7 years is not accurate.
November 21, 2019
By Mihai Andrei
The formula is about mid-way through the article, and it includes a simple calculator.
We learn, as kids, to approximate dog age thusly: one dog year for seven human years. That’s a decent approximation in some cases, but the more you think about it, the more it starts to fall apart.
All dog breeds tend to follow a similar pattern: they reach puberty at 10 months old. Right off the bat, it’s clear that the approximation doesn’t work here, as humans don’t really reach puberty at 6 years. Dogs can also reach 20 years or even more, and 140 years has never been recorded for a human. All in all, while it can give a ballpark estimate, the 7-for-1 approach falls short in many regards.
But now, researchers have come up with a much more accurate formula to assess dog age in human years. This one, at least, is backed by science.
It started as a way to detect factors associated with dog aging, and it focused on a relatively new concept: DNA methylation. The idea is that as we age, our DNA undergoes chemical modifications which can be used as a sort of genetic clock. It’s a way of looking at our body’s wear and tear, as the influence of diseases and unhealthy lifestyle can also be observed (to an extent) with this approach.
It’s not just humans that have epigenetic clocks. Other species have them too — including dogs. Geneticist Trey Ideker of the University of California, San Diego, and colleagues, analyzed the DNA methylation patterns in the genomes of 104 dogs (all golden retrievers), ranging from 4 weeks to 16 years of age. Although just golden retrievers were analyzed, the patterns are very similar for all breeds.
There were remarkable similarities between the DNA methylation of dogs and humans. Although the two species diverged a very long time ago, dogs live in similar environments to humans, and they even have access to similar healthcare.
Simply put, the patterns of DNA methylation in young dogs tended to be similar to those in young humans — the same goes for older dogs and older humans.
Finally, the study also demonstrates that these patterns can be used to translate the age-related physiology of one organism (in this case, dogs) to another organism (humans).
The formula is not linear, and is not exactly simple, but here it is:
Human Years = 16 ln(Dog Years) + 31,
where ln is the natural logarithm.
Inputs
Outputs
Powered by JSCalc.io
The natural logarithm is used because dogs and humans don’t age similarly. Dogs seem to age very quickly in the first part of their life (which is why the age of young pups seem very weird translated into human years), but their ageing process slows down massively compared to that of humans. So the translation dog to human years cannot be linear — it is logarithmic. When your dog is 1 year old, he’s approximately 30 in human years. When he’s 2 years old, he’s 42. He’s around 60 human years by the time he’s 6, but only 70 by the time he’s 12.
It’s a weird thing to wrap your mind around and it is definitely not a perfect translation from dog years to human years, but it works much better than all existing alternatives. It also works to explain why some dogs reach sexual adolescence as early as 6 months old — the onset for that is around 10-14 years for humans. Dogs are adolescent until about 2 years, which in humans lasts until 25 years old. Then, maturity for dogs is around 2-7 years, and for humans around 25-50 years. Similar calculations (but with a slightly different formula) can be carried out for other animals, including cats and mice, researchers conclude.
The study can be read in its entirety for free on biorXiv.
ooOOoo
M’mmm, I think I need a little more time to absorb that!
Learning from Dogs 
This is a great article! I did the calculation & Mags is 69 years old. So, the difference is roughly 8 years from the old way to calculate.
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Well you are a better person than me because, Susan, having republished the article I didn’t do the calculation. (And the copy didn’t come out exactly as laid out. The input/output section didn’t format properly.)
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I did it after I originally read it before your posting. The calculator made me crazy so I used my own.
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Great article Paul, I just need to know the difference between the small and big dogs too, as there are clearly differences between those.
While I only have had big dogs, I use to calculate they are puppies until 1 year, then juvenile year 2 and real adult at year 3. Then they are mature enough to work too fx. as police dogs.
The small dogs seem to become earlier adults, when I have talked to owners of those.
Now an extra challenge for you to find out 😀
My Odin should now be about 60 years, in human years 7 in January.
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I’m being lazy, Irene. For I can never remember the ages of our six dogs.
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Hmmm Paul, do you remember the birthday of your wife? 😀
Maybe she remember the age of the dogs. We can’t be good to remember everything.
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Yes, of course, it’s November 30th. And Jean remembers all the ages of our dogs! What I should do is to record their ages somewhere online so I can refer to them whenever I need to. If fact I shall do that now! Thank you, Irene! But generally my recall is pretty poor.
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Take it easy Paul, there are many things, as I don’t remember well. We do all have our forces and places, where we are not that good.
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I’m not taking old age very well! As Bette Davis said: “Old age isn’t for wimps!” I guess I’m a wimp!
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😀
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An interesting perspective though it doesn’t take into account differences in measuring small vs. large dogs. At 14, Sam is an old guy anyway you slice it, but still my special boy.
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Well I think what it is saying, Monika, is that the formula doesn’t differentiate between small and large dogs.
(Spotted the error later on, should have been doesn’t.)
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