More Complex Formula
Ideker and colleagues studied the methylation patterns on 104 Labrador retrievers, who ranged in age from a few weeks old to 16 years. These were then compared to the methylation patterns in humans.
The scientists were able to devise a more complex formula that better matches the canine-human life stages — but you’ll need a scientific calculator to figure it out.
The formula is “human age = 16 * ln (dog age) + 31,” and you can also use Google to try it for yourself (remember it’s l for “log” and then n for “natural,” all lowercase).
So if your dog is two years old, type, without quote marks, “16* ln(2)+ 31” and hit enter to reveal “42.”
Based on this formula, an eight-week-old pup is approximately equal to a nine-month-old human baby — both being at the stage where they develop teeth.
Labradors’ average lifespan is 12 years, which also roughly corresponds to human life expectancy of 70 years.
“I like to take my dogs on runs, and so I’m a little bit more sympathetic to the 6-year-old now,” said Ideker, because his pet is the human equivalent of 60 under the new formula.
NIH scientist Elaine Ostrander, who co-authored the study, said the new formula had been developed with Labradors in mind, but further investigation could include long-lived breeds — which are generally smaller in size — and short-lived breeds, which are larger.
Such clocks will enhance our understanding of cross-species aging, and help veterinarians in their clinical practice, the team said.