3 Reasons Dogs Don’t Live as Long as Humans, and How to Extend Their Life

Written by Sharon Parry
Updated: September 27, 2023
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There is one downside to owning a dog that none of us like to talk about or even think about. However, the sad fact is that we will, at some stage, have to say goodbye to our much-loved companion. Humans have been grieving the loss of dogs for thousands of years. So, why don’t dogs live longer than humans? And just as importantly, what can we do to increase the life expectancy of our own dogs? Let’s attempt to answer the question, “Why don’t dogs live longer?” and come up with some practical steps that you can take to increase the chances of your dog having a long and happy life. There are no guarantees here, but anything is worth a try when it comes to our four-legged friends, right?

There are several reasons why dogs do not live as long as humans.

Why Don’t Dogs Live Long?

When we ask the question, “Why don’t dogs live longer?” what we actually mean is, “Why don’t dogs live as long as we want them to, which is at least as long as us?” The answer is quite complex and there are many factors that decide how long a particular species will live.

Size Matters

An adult female Pie Bald Great Dane sitting on green grass with sunlight shining on her.

Dogs are smaller than humans so tend to live shorter lives.

©Arthur Villator/Shutterstock.com

On the whole, we see that larger species live longer than smaller ones. So, elephants live for 70 years but fruit flies live for just 24 hours. We are bigger than dogs, so you would expect us to live longer. The theory is that smaller animals have a higher metabolic rate as indicated by a faster heart rate. They simply run out of energy sooner and die. However, there are so many exceptions to this rule that it cannot be the whole explanation. Parrots are quite small and have a very fast heart rate but they can live into their eighties and beyond.

Evolutionary Pressures

In ancient times, wild dogs faced more evolutionary pressure to survive than humans, so they evolved to develop more quickly.

©Bart Swanson / Creative Commons – License

The real answer is probably to do with evolutionary pressures. These are the hazards in the environment that threaten an animal’s survival. It could be predators, competition for food, or lack of water. Larger animals, like elephants, are less likely to be hunted by predators and so one generation can last for a long time. However, a small mammal like a mouse lives a very hazardous life and is very likely to be killed so it makes sense to have a fast turnover.

In ancient times, wild dogs would have faced more evolutionary pressure than early humans (who had very few predators) and so we lived longer. Everything about dog development is therefore speeded up. They get teeth, can live independently, and start reproducing a lot quicker than we do. Sadly, that also means that they die sooner too.

Human Dog Breeding Practices

Smiling charming adorable sable red merle and white border collie male outdoors portrait on spring time with park background. Most clever dogs breed in the world - herding border collie

Many human dog breeding practices have resulted in dogs that have genetic defects that hamper their life expectancy.


Another reason that dogs don’t live very long is connected to dog breeding practices. Many breeds have genetic defects that are passed down through the generations and lower the average life expectancy of the breed. If you can get an individual dog that does not have inherited conditions, they could live much longer than the average figure. This is why it is so important to do your research before you buy a pup. Studies have shown that inbreeding (breeding dogs that are genetically related) is associated with shorter lifespans.

What Affects Dogs’ Lifespans?

Even though all our domestic dogs belong to a single species, they have a remarkably variable lifespan. Some dogs die in just a few years but others can reach two decades. Why don’t dogs live longer? There are several factors that come into play.


There is a general understanding that larger dogs have shorter lifespans. It is thought that this is because their organs have to work harder to keep them going and simply wear out quicker. As an example, a Great Dane would be expected to live for 8-10 years but a Yorkshire Terrier can live for up to 16 years.

An in-depth study from the UK has recently recorded the life expectancy of many popular dog breeds. And it is clear that size is not the only determining factor. Also, average life tables are not actually that useful if you want to work out how many years of life your own dog has left.

Let’s consider a Chihuahua as an example. Their average life expectancy at birth is 7.9 years. So, if you have just rescued a 6-year-old Chihuahua you may be feeling a bit sad about how many years you will have together. There is no need to feel sad! The study also shows that many Chihuahuas die as young dogs which drags down the average life expectancy. However, once a Chihuahua has made it to the age of 6 years, they are very likely to go and live to the impressive age of 15 years!


Another reason to not rely on average breed lifespan tables is that some breeds don’t obey the rules. Let’s take a closer look at the French Bulldog, or Frenchie as they are affectionately called. These designer dogs are hugely popular right now and pups can sell for huge sums of money. Because they are a small dog, you would expect them to have a long lifespan. Sadly, in common with many other flat-faced breeds, they can face multiple health issues. The study we detailed above found that the average life expectancy at birth was only 4.5 years.


As an owner, there is not much that you can do to alter the genetic profile of your dog. However, you can do a lot to alter their lifestyle to give them the best chance of living longer. By lifestyle, we mean diet, home environment, exercise, mental stimulation, and health and safety precautions to protect from accidents.

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How to Make Your Dog Live Longer?

What you have read so far may sound a little depressing but we also have some good news to share. Domestic dogs are living a lot longer than they used to! In fact, scientists estimate that their lifespans have doubled in the last 40 years. This is probably because we now understand a lot more about the way in which diet and lifestyle can impact dogs’ life expectancy. There have also been huge advances in veterinary medicine.

There is also a wealth of research being carried out into how we can help our dogs live longer. One excellent example is The Dog Aging Project which aims to “understand how genes, lifestyle, and environment influence aging…and use that information to help pets and people increase healthspan, the period of life spent free from disease.”

Research produced by collaborations such as the Dog Aging Project results in advice that we can all follow to help our dogs live longer.

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Injury and Disease

Sadly, thousands of dogs die every year from injuries. This can be from falls, collisions with vehicles, and countless other incidents. You can reduce the risks of an accident by making your dog’s safety a priority.

Start with dog training. A badly trained dog is not under control and an out-of-control dog is more likely to have an accident. There are lots of dog training books and courses that you can try.

Buy some safety gear such as leashes and harnesses with fluorescent strips that show up at night. When your dog travels in a car or motorbike use a harness and/or an appropriate carrier.

Many dog diseases can be prevented with vaccination and your vet will advise on what is needed in your area. Also, some diseases can be transmitted by fleas, ticks and worms so make sure that you use preventative treatments for these parasites.

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Tooth Decay

Dental disease may sound like a trivial matter but can have a direct effect on how long your dog lives. Dogs with gum disease have a lot of bacteria and chronic inflammation in their mouths. This can lead to kidney, liver, and heart disease which can all be fatal.

To look after your dog’s dental health, brush their teeth with a special dog toothpaste several times a week. Also, give them dental treats and chew toys that scrape off plaque.

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Maintain a Healthy Weight

Obesity is a serious canine health problem in the US with an estimated 40-45% of dogs aged 5-11 weighing more than they should. Obese dogs are more likely to get cancer, heart disease, diabetes mellitus, hypertension (high blood pressure), osteoarthritis, urinary bladder stones, and issues if they need a general aesthetic. All of these reduce life expectancy. If you are struggling to control your dog’s weight, you should seek advice from your vet. They may suggest that you transition your dog to a weight management diet.  

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Exercise is very important when it comes to increasing lifespans. Dogs that have enough exercise for their breed have healthy hearts and lungs and keep their joints strong. Dogs love nothing more than to head off on an adventure with their human companions. When you are busy with chores, try an automatic fetch machine to keep your pet occupied.

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Mental Stimulation

Cognitive decline is a problem in older dogs. It may be helpful to keep your dog mentally stimulated all their lives. Dogs love interactive toys that make them think and exercise their minds as well as their bodies.

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Spaying and Neutering

Overall, intact dogs (males and females that have not been neutered or spayed) have shorter lifespans than dogs that have been fixed. This is because an intact dog is more likely to roam and get into fights and suffer trauma and infection. Fixed dogs are more likely to get some types of cancer though.


Many causes of death in dogs can be avoided with vigilance on the part of the owner. This could simply be keeping an eye on what your dog is doing. It also involves taking them to the vet for investigations if you think that something is wrong. Many canine conditions can be successfully treated if they are caught early.

Summary of 3 Reasons Dogs Don’t Live as Long as Humans

1Size Matters
2Evolutionary Pressures
3Human Dog Breeding Practices

What Dogs Have the Longest Lifespans?

Infographic of 10 Dogs With the Longest Lifespans
Toy poodles and Shih Tzus live on average for 10 to 18 years.

The fact that dogs have relatively short lifespans compared to us humans is a tough pill to swallow. But if you love the animal dubbed “man’s best friend,” and are looking to invest in one, it would be a good idea to consider the lifespan of the breed. While some dog breeds only average up to 10 years, others can live 15 to 20 years. Below is a list of 10 dog breeds that have the longest average lifespans for your consideration:

RanDog BreedAverage Lifespan
1Toy Poodle10-18 years
2Shih Tzu10-18 years
3Chihuahua14-16 years
4Pomeranian12-16 years
5Dachshund12-16 years
6Maltese13-15 years
7Australian Shepherd12-15 years
8Lhasa Apso12-15 years
9Yorkshire Terrier11-15 years
10Beagle10-15 years

The photo featured at the top of this post is © NayaDadara/Shutterstock.com

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About the Author

Dr Sharon Parry is a writer at A-Z animals where her primary focus is on dogs, animal behavior, and research. Sharon holds a PhD from Leeds University, UK which she earned in 1998 and has been working as a science writer for the last 15 years. A resident of Wales, UK, Sharon loves taking care of her spaniel named Dexter and hiking around coastlines and mountains.

FAQs (Frequently Asked Questions) 

Which dogs live the longest?

Lifespans are very variable and are notoriously difficult to predict. However, the popular breeds that tend to live the longest are Jack Russell Terriers, Chihuahuas, Cockapoos, and Toy Poodles. Also, the dogs that live longest are the healthy ones!

How long can a dog live?

The oldest recorded dog was an Australian Cattle Dog who lived on a ranch in Victoria, Australia. He was called Bluey and lived between 1910 and 1939 when he died at the grand old age of 29 years and 5 months!

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