Is a “Dog Year” Really Seven Human Years?

When it comes to working out dogs’ age, we’ve always been told that one year in human years is the equivalent of seven years in doggy terms. This myth was heightened during the ‘80s when a string of commercials graced our airwaves and told us that one poor dog (the adorable Danny) was 14 – “That’s like 98 to you and me.” Well, you don’t really need to be a mathematician or a dog expert to realize that that number doesn’t sound quite right. So is a ‘dog year’ really equivalent to seven human years?

It’s all a myth

Despite these commercials advocating the idea that one human year is the equivalent to seven years, scientists have known for centuries that that this isn’t correct. In fact, the first attempt to equivalate dog years with human years goes all the way back to the 13th Century, when a note was inscribed at Westminster Abbey, noting that the ratio was 9 to 1 – and that dogs lives 9 years and men lived 81 years (although we now know this isn’t correct either).

The myth is a marketing ploy

Many researchers believe that the origin of the myth came as a marketing ploy – and a pretty effective one at that, considering millions of people around the world consider the idea to be true. A veterinarian has offered the idea that this marketing ploy was designed to (falsely) educate dog owners of the health risks associated with their pets – encouraging them to take their dogs to the vets more than they previously would.

The math is all wrong

One article in Business Insider has disputed the claims that people are aging slower than dogs, slower in approximately seven years, because in reality – it just does not work. If this equation were correct, this would mean humans are able to start reproducing just 7 years old and could live to the grand old age of 150. Which of course, has yet to happen.

The real answer is pretty complex

The actual answer as to what constitutes a dog and a human year is pretty complex – because it varies for each breed of dog, and is different every year. For example, dogs normally reach their sexual maturity at just one year old – which in human years would be around 12-15 years-old. Therefore, in their first year of life, dogs age nearly 15x faster than humans.

Various breeds are different

When it comes to dogs’ maturity, it gets even more complicated when you look at the different breeds. Smaller breeds of dogs grow old faster than their larger friends – and smaller breeds also outlive the larger breeds. This means when it comes to deciding the dog: human ratio, it’s going to be different for each breed.

How do you actually calculate your dog’s age?

Despite the difficulties behind it, it is still easy to determine the dog’s age – and it’s not done by a simple multiplication. Find a chart online, or an authority website for your dog’s breed to find out how long your dog’s breed is expected to live for. Divide that by four, and you have the milestones to look out for.

This is based on the assumption that an average human lives until about 80 years old, and has four ‘milestone’ birthdays – 20, 40, 60 and 80. So, if your dog is expected to live for twelve years, then divide twelve by four to get three. So when it is three, it is ’20’ in human years, when it is six, it is ’40’ in human years, etc. Alternatively, your vet can do it for you.