We always thought we knew how to calculate our dog's age in human years. It's been widely believed that one dog year equals seven human years, but researchers say they now have a new formula.
According to this piece from Popular Mechanics, researchers studied DNA mehtylation with the genomes of 104 Labrador retrievers between 4 weeks old and 16 years of age and have used the data to come up with new, more accurate ways to figuring out your dog's age.
It involves complicated chemistry and gene studies. Among other things, the researchers found that for both humans and the Labrador retrievers, "areas with high rates of mutation – show similar rates of methylation." Steve Austad, an evolutionary biologist and aging expert at the University of Alabama-Birmingham, noted "They’ve shown that there’s a gradual increase in DNA methylation in both species with age."
What that means is life stages for a dog closely syncs with life stages for humans early on (for example, that babies and puppies start teething around equivalent ages, roughly 7 and 9 months), but after a few years, dogs age more slowly compared to their human counterparts. This is where natural logarithms come into the calculations.
As you might imagine, the formula for calculating your dog's age is rather complex. It requires multiplying the natural logarithm of your dog’s age by 16 and then adding 31.
The equation works out to 16 x ln(your dog’s age in human years) + 31, where the "ln" means "natural log," if I remember correctly from high school and college math classes. Another way of putting it would be to say that human age is the same as 16 times the natural logarithm of dog age plus 32. Or maybe that made it more confusing.
You can use this natural logarithm calculator, too. Just enter your dog's age to get the natural log value, then multiply it by 16, and add 31 to the total. Easy peasy, right?
By the way, does this mean we have to change the formulas for that "In dog beers, I've only had one" t-shirt??