How old is my dog? One dog year is not equal to 7 human years, say scientists who come up with new formula to find pets' age
The older method, which equates one dog year to seven human years, is a myth, say scientists.
One dog year is not equal to seven human years. Thanks to this age-old myth, dog owners have been inaccurately calculating their pet's age in human years. Now, researchers from the University of California have proposed a new formula, which, they say, does a better and more accurate job at calculating the human equivalent of your dog's age.
To arrive at this formula, scientists turned to a method that estimates people's age by measuring certain changes that occur in their DNA. These changes are the result of aging, which build up with age. This feature - showing similar changes or patterns as they age - is shared by other animals such as mice, dogs, chimpanzees, and wolves. So the team decided to adopt the same method to calculate the dog's age in human years.
These changes that can help scientists estimate the biological age of dogs and humans are a result of a chemical, methyl group. They get added to the DNA in patterns that correspond to a dog's or a human's age.
“We already knew that dogs get the same diseases and functional declines of aging that humans do, and this work provides evidence that similar molecular changes are also occurring during aging”, Matt Kaeberlein, a biogerontologist at the University of Washington in Seattle, who was not involved with this research, told Science.
In this study, the team focused on a particular breed: Labrador retrievers. They examined how patterns of changes in the DNA of 104 dogs - ranging from 4 weeks to 16 years of age - changed with time and compared them with DNA from 320 humans aged between one and 103 years.
From their analysis, the researchers found out that dogs and humans showed similar age-related patterns in certain regions of the DNA. They saw similar patterns between young dogs and young humans as well as old dogs and old humans.
Further, dogs’ and humans’ life stages also seem to match, say the researchers. They show that a 7-week-old puppy is equal to a 9-month-old baby in human years. The formula also gets it right while estimating the average lifespan of dogs and humans. A 12-year-old Labrador retriever is equal to a 70-year-old human, the study says.
Steve Austad, an evolutionary biologist and aging expert at the University of Alabama in Birmingham, told Science that he does not find the results surprising. He thinks the technique could reveal far more interesting results if applied to issues like the different life spans among different dog breeds.
You can find the calculator here.
The findings are published on the pre-print resource bioRxiv.