It’s often difficult for dog lovers to accept the fact that dogs tend to age must faster than humans. Puppyhood in dogs always seems to just fly by. One minute the puppy is romping around in a clumsy manner, and the next, 80 pounds later, the pup has already grown into a large representation of his breed. The path from adulthood to senescence can feel quite brief as well. Fortunately, by calculating a dog’s age, and comparing it to a humans’, it’s possible to at least keep track of Max’s advancements in life.
Using the 7:1 Ratio
A few years ago, conventional wisdom suggested that converting a dog’s years into human years was quite simple; all that was needed was just solving an easy equation. The belief back in time was that a dog’s year was the equivalent of seven human years. This meant that, in order to get the equivalent of a dog’s age in human years, the dog’s age just had to be multiplied by seven.
So if Max was 1 year old, if he were human, he would be a 7-year- old child, and if he was 7 years old, he would be a 49-year-old man. This has raised many doubts from dog experts who were scratching their heads in wonder. Respected scientist and Professor of Psychology, Stanley Coren, was quick to point out one major flaw in an article for Live Science. He explained that a dog at the age of 1 is already capable of reproducing, while a 7-year old child is obviously not!
It’s quite unclear where the 7:1 theory came from or who invented it, but what’s known is that it first made its appearance in the old math text books children used in the 1960’s. Perhaps those who were in school back then may vaguely remember some math problems requiring them to calculate the age of man’s best friend by using the 7:1 ratio.
Factors Known to Affect a Dog’s Lifespan
A better knowledge of a dog’s aging process, along with several factors known to influence lifespan reveals that, contrary to popular belief, the 7:1 ratio offered only an oversimplified glimpse of a dog’s true age. There are really many factors to keep in mind that this ratio unfortunately overlooks. The following are some factors that have an impact on attaining accurate dog- to -human age calculations.
The Size Factor
The Breed Factor
The Weight Factor
By looking at other mammals living on this planet, a large size seems to suggest a longer lifespan. Indeed, whales, gorillas and elephants are known to live longer than smaller critters such as voles, shrews and mice, explains Daniel Promislow, a professor teaching genetics at the University of Georgia in an article on the BBC website.
In the dog world though, the opposite seems true. It’s a known fact that smaller dogs tend to live much longer than larger breeds. Small dogs are often estimated to live in their late teens, often reaching the ripe age of 16 years. Larger dogs, regrettably, have often much shorter life spans, most reaching an average of 7 or 8 years old. Finally, medium dogs rank somewhere in between, living an average of 10 to 13 years of age.
Smaller dogs also tend to reach skeletal and reproductive maturity more quickly in their first years; whereas, larger dogs tend to lag a bit behind. For instance, a small dog is usually already mature by the age of 12 to 15 months, while a large dog will be considered mature at around 2 years of age. This is quite bizarre if you think that a small dog is considered older in its first few years, but then gets younger after the age of five!
Breed can also be an important factor. Each dog breed has an average lifespan that varies according to its genetic potential. For instance, giant dog breeds such as Deerhounds and Great Danes have quite a short life span; indeed, they are considered elderly at just 6 to 8 years. Smaller dog breeds have more luck on their side with 40 percent of them living more than 10 years. Perspective dog owners looking for a dog breed to enjoy for many years should consider a Maltese or a Miniature Schnauzer. According to the World Atlas of Dog Breeds, both these popular breeds have the potential for living 15 years or more!
What about mixed breeds though? Unfortunately, most formulas and calculators don’t offer an option for mutts, but according to Dan O’Neill, who has been conducting research on the subject for a PhD at the Royal Veterinary College, crossed breeds are estimated to live about 1.22 years longer than purebred dogs.
With statistics showing small dogs living longer it’s easy to deduce that size is still the most relevant factor, but it turns out that weight matters much more than height. Indeed, a study co-authored by Kimberly Greer, revealed that dogs weighing less than 30 pounds were the ones that had the longest lifespan.
There are several more factors that may have an impact on a dog’s longevity. According to Steven N. Austad, a professor and researcher on aging at the University Of Texas Health Science Center, female dogs tend to have a longer lifespan than males, even though this isn’t as evident in humans.
Another factor is health. The lifespan of certain purebred dogs is often considerably lowered because of genetic predisposition to deadly conditions. Reputable breeders may try to diminish this factor by selectively breeding stock with a history of reduced health problems in their bloodlines. Dog owners may further help their dogs attain longer longevity by feeding them a nutritious diet, preventing obesity and providing good care.
Finally, the comparison with human years also poses some problems. Dogs tend to mature more quickly than children. As mentioned, a 1- year- old dog is more like a pre-teenager or a teen-ager, rather than a 7-year old child! This flaw has caused experts to re-evaluate the 7:1 ratio and find more accurate systems.
More Accurate Dog Age CalculatorsSo with all the above variable factors in mind, how can a dog’s age be accurately calculated in human years? Fortunately, nowadays more accurate formulas have been crafted. There are several varieties available, but some are more accurate than others. The following are some examples.
The Dog Years Calculator offered by Online Conversion keeps into account the fact that dogs mature much faster than humans in their first couple of years. Therefore, for the first 2 years it calculates 10.5 dog years per human year, and after that, 4 dog years per human year. While this is much more accurate than the seven-to-one rule, it’s still missing some important points that can make a big difference.
An even more accurate calculator was crafted by the WebMD website. In this case a chart is offered. The beauty of this chart is the fact that it keeps into account the dog’s weight. Dogs are categorized into 3 groups: small dogs weighing 20 pounds or less, medium dogs weighing anywhere between 21 and 50 pounds and large dogs weighing over 50 pounds.
As mentioned, because different dog breeds age at varying speeds, the breed of the dog plays also an important factor when it comes to calculating age and its equivalent in human years. The Pedigree website has a dog age calculator based on individual breeds. This should be as close as dog owners can get to attaining accurate calculations as it should automatically consider genetic longevity, size and weight.
What if You Don’t Have an Age?
What about dog owners who cannot make calculations because they have rescued their dog and they have no idea of how old their companions are? There is good news for them. An approximate age can be calculated by simply looking at the dog’s teeth. Most veterinarians are trained to estimate age by looking at some important dental details. Yes, horses aren’t the only creatures blessed with teeth that reveal their age!
In young puppies, age can be estimated by looking at the eruption of the adult, permanent teeth which grow at distinct times. The age of older dogs can be estimated by looking at their level of wear and tear and the presence of tartar. An in-depth physical exam by an experienced veterinarian may further reveal helpful details about a dog’s age. The condition of a dog’s eyes, bones, joints, muscles, and internal organs may indeed speak volumes and reveal important clues.
The Bottom Line
It’s a known fact that dogs are the most unique and diversified animals populating planet earth. Centuries of selective breeding have created dogs that vary considerably in shape, size, color, height and weight. Therefore, it’s quite normal for man’s best friend to have a varied lifespan. While no dog to human age calculators have yet been scientifically proven to be accurate, the approximations of some formulas can be quite reliable. The next question though is: what about adding in the factors that influence human longevity?