Do Dogs Really Age “Seven Dog Years” for Every Human Year?

You’ve probably tried to work out how old your dog is in “dog years”, right? It’s a fun exercise and can give you a rough idea. But it’s also a big simplification. Biologically, a dog can have puppies within its first year, but in Sweden it’s forbidden to mate a female dog before she is 18 months old. A human, on the other hand, can’t have children at age seven. So that rule of thumb is a bit too simplified.

There is now a new way to calculate a dog’s age, based on a study by researchers at the University of California, who followed 104 Labrador retrievers over several years. The results showed that dogs’ biological clocks are similar to those of humans and that dogs’ and humans’ life stages line up. The difference is that a dog’s biological clock ticks much faster than a human’s the older the dog gets.

In the first human year, your dog is 31 years old in dog years; in the second human year, it increases by 11 years; in the next human year, by six years. So the difference per year shrinks as more human years pass.

See the list below to find out how old your dog really is:

• 1 human year = 31 dog years
• 2 human years = 42.1 dog years
• 3 human years = 48.6 dog years
• 4 human years = 53.2 dog years
• 5 human years = 56.8 dog years
• 6 human years = 59.7 dog years
• 7 human years = 62.1 dog years
• 8 human years = 64.3 dog years
• 9 human years = 66.2 dog years
• 10 human years = 67.8 dog years
• 11 human years = 69.4 dog years
• 12 human years = 70.8 dog years
• 13 human years = 72 dog years
• 14 human years = 73.2 dog years
• 15 human years = 74.3 dog years
• 16 human years = 75.4 dog years
• 17 human years = 76.3 dog years
• 17 human years = 76.3 dog years
• 18 human years = 77.2 dog years
• 19 human years = 78.1 dog years
• 20 human years = 78.9 dog years

So with the help of this clock, it is possible to estimate age and even make a prediction about how long a person or dog is expected to live. But remember that this is only a general calculation. The biological clock is of course affected by disease, lifestyle, and genetics and the impact they have on our bodies.

Source: biorxiv.org