Wednesday , May 8 2024
Dog Age Vs. Human Age

Dog Age Vs. Human Age: Debunking the 7-Year Myth

The idea of dog years is common in pet-owning families, bringing attention to the dog age vs human age comparison.  There are many theories about how dogs age and how it differs from that of humans, but the consensus seems to be that 1 human year is 7 dog years.

This is common, but is it accurate? And where did this theory come from? This article will dive into the details to give you precise ways of estimating dog years and a better understanding of the process. Let us get into the details and find out more about how dogs age;

Dog Age Vs. Human Age 

Like most animals, dogs age faster than humans by several years. Many people believe that a dog ages 7 years for each human year, but this concept is not entirely accurate. Dog aging has a lot of complexity and isn’t as straightforward as humans.

There is faster aging in dogs than in humans, but there is also a difference in the specific dog species. This is not the case in humans, as everyone ages the same regardless of race or origin.

The breed of dogs mainly affects the size, and there is a correlation between the size of adult dogs and how fast they age. 

Generally, larger dog breeds will age more quickly and have shorter life expectancies. Smaller breeds like Chihuahuas tend to live longer.

Medium-sized, average dogs fall somewhere between the two categories. This is puzzling since small species like rats have short life spans in other animals while large animals like whales and elephants have longer life spans.

Scientists are baffled over the cause of the reversed aging process in dogs, and it is still a mystery why they don’t obey nature. This curiosity started ages ago with French scientist A. Lebeau investigating dogs and aging.

According to Lebeau, dogs age between 15 and 20 years faster than humans in the first year of a dog’s life. The rate of aging would then slow down in later years based on Lebeau’s theory.

According to the American Kennel Club, 7 dog years to 1 human year became popular in the 1950s. This occurred since humans lived for about 70 years and gods for 10, so people oversimplified it to create the 7:1 ratio. 

Modern specialists have proven this idea wrong even though the general concept is accurate. According to Dr Melissa Berg, the 7:1 ratio is too simple and outdated, even though dogs age significantly faster.

The easiest way to debunk the 7:1 ratio theory is to consider reproduction since dogs can reproduce as soon as they reach sexual maturity. Some small dog breeds will mature at six months or younger than that.

When you convert that using the 7:1 ratio, the theory falls apart and makes no sense. There isn’t any accurate way of knowing your dog’s age in dog years, but you can get it to an approximate value.

The aging of a dog depends on their size, so here is a quick table you can use to determine your dog’s age if you know it’s human years. 

Human Years Small(Under 20 lbs) Medium(21-50 lbs) Large(51-100 lbs) Giant (Over 100 lbs)
1 15 15 15 12
2 24 24 24 22
3 28 28 28 31
4 32 32 32 38
5 36 36 36 45
6 40 42 45 49
7 44 47 50 56
8 48 51 55 64
9 52 56 61 71
10 56 60 66 79
11 60 65 72 86
12 64 69 77 93
13 68 74 82 100
14 72 78 88 107
15 76 83 93 114
16 80 87 99 121

This estimate won’t be 100% accurate for all cases, but it will get you close enough. A general rule of thumb when considering your dog’s age is as follows;

  • The first human year equals about 15 ears for a medium-sized dog.
  • The second year for a dog is about nine years for a human; after that, each human year is around 5 years for the dog. 

How Do Researchers Come Up With The Dog Age Vs Human Age Numbers?

All the numbers and year differences must be eye-opening, but they raise many questions. The first and most significant question is how scientists develop these estimations. Many elements go into the decision, so it is hard to pinpoint an age for dogs.

Cats and dogs are generally considered senior when they reach 7 human years old, but most of them live much longer than that. Larger dog breeds are seniors between ages 5 and 6 since they have shorter lifespans.

A comparison of development rate, growth rate, and life span allows scientists to get estimates of how fast dogs age. By monitoring human development and lifespan and comparing it to that of dogs, we can look at life through our dogs’ eyes. 

Why Do Smaller Dogs Live Longer Than Larger Dogs?

The reversed pattern of aging is an intriguing phenomenon to researchers all over the planet. They have had trouble explaining the relationship between a dog’s body mass and lifespan since it seems to be opposite from the other mammals. 

The general idea is that animals with larger body mass, like humans and elephants, tend to have longer lifespans than those with smaller bodies. So why do smaller dog breeds have longer lifespans than larger dog breeds?

Cornelia Kraus is an evolutionary biologist at the University of Göttingen, and he has researched the topic. According to him, large dogs live acceleratedly, and their lives unwind quickly.

According to scientists, an increase in body mass by 4.4 pounds reduces a dog’s lifespan by about a month. The exact reason for this difference is still a mystery, but scientists have a lot of theories on it.

According to Dr. Kraus, larger dogs have accelerated growth, which leads to a higher likelihood of abnormal cell growth and death from cancer. 

This faster growth also means they are more likely to die of age-related sicknesses sooner than smaller dogs.

Many studies are going into creating a better understanding between growth and mortality in dogs. The study of canines is a highly monitored field of science since dog lovers want to extend and improve their pet’s lives.

The dog aging project is dedicated to understanding how dogs age. Additionally, there are plans to use geroscience research to help increase dog lifespans so they have longer and healthier lives with their owners. 

How To Know That Your Dog Has Aged

As a dog owner, it is vital to keep track of your dog’s age so that you know when they get old. Older dogs need extra care to ensure they live their entire life, and you might not know their age.

If this is the case, don’t get alarmed; there are many physical signs to look for and potentially tell if your dog is old. 

An excellent example of such signals is the teeth. At seven months, all of your pup’s teeth will have grown in and be relatively sharp and fresh.

Between 1 and 2 years, the teeth will likely be duller and might be slightly yellow, depending on the dog’s breed and hygiene. 

The dog will be old between 5 and 6 years, so they will start showing signs of dental diseases, and they need extra care for comfort.

Like humans, dogs get gray hair when they age, so this is another sign to look out for and tell when your dog is getting old. Other common signs of aging in dogs include;

  • Cloudy eyes or poor eyesight
  • Trouble hearing
  • Consistently low activity level
  • Stiff muscles and joints
  • Behavioral changes like confusion, anxiety, irritability, and accidents around the house. 

Most of these signs could also indicate sickness rather than old age, so if you notice them, go to the vet for a clear guideline. 

The vet is also better positioned to look at the dog and give you a reasonably accurate estimate of their age and a way forward.

Remember, a larger dog will age faster, so you should look for signs around 5 or 6 years old. Once the dog goes into the senior year, keep a close eye on them and ensure you provide a healthy diet and medical care.

Regular vet checks and pet insurance will be the best course of action to ensure your best friend gets the best care. 


This article has given you all the information to clear up the question about dog age vs human age. 

Dogs age significantly faster than humans, about five dog years for each human year. Larger dogs will age faster and need closer attention in old age.

You need to take better care of your dog once it gets to its senior years, and you should get insurance for it. 

An insurance plan will help cover the bill in case of an accident or major illness that would otherwise cost much money to treat.

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