Quantitative Translation of Dog-to-Human Aging [pdf]

From the Study's results:

Dogs (Labrador Retrievers were used in this study) have roughly equivalent cellular ages to humans:

    | Human Years         | Dog Age Equivalent |
    |---------------------+--------------------|
    | 0 to 6 months       | Juvenile           |
    | 6 months to 2 years | Adolescent         |
    | 2 to 7 years        | Mature             |
    | 7 years and older   | Senior             |

Fantastic. DNA is not just a blueprint, it is also a state machine. I like the use of the word "methylome" to represent the state machine. The four stages of aging are intuitive; I'm pleasantly surprised that they map so nicely to the quantifiable methylome.

I think the four stages roughly apply to all vertebrates. Divers familiar with Humann and DeLoach's field guide Reef Fish Identification quickly learn that the Juvenile and Mature phases of many tropical fish (e.g. many angelfish) are drastically different.

It would be interesting to see how well this translates between small, long-lived dogs and the very large but significantly shorter-lived dogs- particularly how the differences there compare to those between other mammals.

There’s obvious reason to suspect that the aging process in mice (which occurs over ~3 years) is just a different process than the aging process in humans (which occurs over 80+ years), which would obviously be a big problem for all the research into aging that relies on animal models. If dogs, one species with a very diverse set of phenotypes, could serve as a meta-model for how aging processes differ between short- and long-lived creatures, that would be very useful.

So many jokes will need to be rewritten now the linear 7 to 1 rule has been debunked. However the dogs on the internet is much more credible with a one year old dog equivalent to a thirty year old human on this new nonlinear function.

Follow the link to learn the conversion factor, stay for the dog/Tom Hanks comparison photos.

This is a similar curve for cats even though domestic cats tend to live substantially longer than dogs despite having a fairly similar early growth curve. The world record longest living cat was 38 while the oldest dog was just under 30. Cat life expectancy is 15-20 years, dogs 12-15 and for humans around 80. But the longest living humans are in the 120-130 range, not 150 if we linearly extrapolated from cats and dogs. Life expectancy and maximum age favor cats over humans in this respect.

I wonder how much dogs would benefit from intermittent fasting considering their ancestors only ate a few times a week. (Assuming what I know about wolves from cartoons is correct.)

I'm pretty sure my 5-year-old dog does not behave like a 55-year-old. (Comment from Roly himself, blogging at https://facebook.com/gienusofroly : UNBEBLEIVABLE!)