Comparing One Year of a Dog to Seven Years of a Human Is a Myth

Direct Correlation Doesn’t Work 
The team of scientists from San Diego University in California came up with a new technique that doesn’t use the direct correlation between the dog’s age and the human’s age and it shows that dogs age much faster than people early on in their lives and then the process gradually slows down. The research also showed certain connections between human and dog development. For example, it showed that approximately a seven-week-old puppy is as old as a baby of nine months. 

DNA-based Research
The whole research was based on the molecular changes on the surface of DNA in a sample of 104 Labradors from the age of 0 to 16 years. Thanks to that they found out that molecular changes, the so-called process of methylation, influence the expression of certain genes. During their lives, dogs go through “shutting down” of certain genes they no longer need or their bodies fix genes in which mutations occur. 

Common Milestones for Dogs and People
Both people and dogs share the processes of shutting down or fixing the genes as well as they also have some similar physical life milestones, such as the replacement of teeth, the onset of puberty or sexual maturity. However, the time when these occur is different. 

Aging Is Fastest until One Year of Age
The whole research also came up with a formula that can help to determine the age of every dog. It means that a one-year-old puppy is on a similar level as a 31-year-old human. The human equivalent of a two-year-old dog is 42 years, and a three-year-old puppy is approximately as old as a 49-year-old human. This pattern makes it clear that the aging of dogs gradually slows down. At this rate, a 7-year-old dog can be compared to a 62-year-old human. 

The following table shows the age of a dog and its equivalent in human years:

1 dog year  31 human years
2 dog years  42 human years
3 dog years  49 human years
4 dog years  53 human years
5 dog years  57 human years
6 dog years  60 human years
7 dog years  62 human years

Researchers also introduced a formula that can be used to for further calculations. However, it’s not as simple as the previously used one with direct correlation. The human years of a dog can be calculated as six times the natural logarithm of a real age of a dog increased by the constant of 31.