How old is your dog, really?

The old rule that one dog year equals seven in human years is not true. What the researchers found was that dogs age differently than humans. For example, Trey Ideker of the University of California, San Diego pointed out that a nine-month-old dog can have puppies. If you do the math, it is obvious that the 1 year equals seven does not work out. They studied Labrador Retrievers to see how they age on a molecular level by comparing changes in the methylation pattern. They discovered that dogs age rapidly at first and then slow down later in life.    

According to the article “The comparison revealed a new formula that better matches the canine-human life stages: human age = 16 ln (dog age) + 31. Based on the new function, an 8-week-old dog is approximately the age of a 9-month-old baby, both being in the infant stage where puppies and babies develop teeth. The average 12-year lifespan of Labrador retrievers also corresponds to the worldwide life expectancy of humans, 70 years.”

The researchers noted that they need to do more studies because different breeds age at different rates. Having a more accurate way to measure a dog’s age will help both dog owners and veterinarians better appreciate and care for dogs.

Journal Reference:

  1. Tina Wang, Jianzhu Ma, Andrew N. Hogan, Samson Fong, Katherine Licon, Brian Tsui, Jason F. Kreisberg, Peter D. Adams, Anne-Ruxandra Carvunis, Danika L. Bannasch, Elaine A. Ostrander, Trey Ideker. Quantitative Translation of Dog-to-Human Aging by Conserved Remodeling of the DNA MethylomeCell Systems, 2020; DOI: 10.1016/j.cels.2020.06.006

Cite This Page:

Cell Press. “How old is your dog in human years? New method better than ‘multiply by 7’.” ScienceDaily. ScienceDaily, 2 July 2020. <>.