A common question among pet parents is why small dogs live longer than big dogs? In reality, does size really matter when it comes to the average lifespan of a dog? The short answer to this question is yes, dog size does affect lifespan. But is there anything that pet parents can do to help their dog — no matter their size or breed — to live a longer and happier life? Let's find out!

Why Do Small Dogs Live Longer?

One thing to keep in mind when talking about the average lifespans of small, medium, large and giant breed dogs is that these are average figures. This means that some dogs will live shorter than the average and other dogs will live longer. But if this is the case, why do small dogs live longer than large dogs?

It is believed that large dogs simply age more quickly than small dogs. It's not uncommon for some giant breeds to gain upward of 100 pounds (45.36 kilograms) in a year, whereas some small breeds may only gain 10 pounds (4.54 kilograms). This rapid growth associated with some giant breeds appears to negatively affect their longevity. When looking at the average lifespans of dogs based on breed, there are often certain generalizations; however, even within the same size category, some dogs may live longer than others due to common health issues associated with a specific breed.

What Is the Average Lifespan of a Dog?

The average lifespan of a dog is dependent on whether they're a small, medium, large or giant dog breed — so the answer varies.

Small Breed Dogs

Smaller breeds, like the Chihuahua and Maltese, which are popular due to their portability, are considered on average to be less than 20 pounds (9.07 kilograms) and have an average life expectancy of 10 to 15 years. However, the oldest known Chihuahua on record, named Megabyte, passed away at 20 years and 265 days old.

Medium and Large Dog Breeds

Medium dog breeds, like many of the spaniel breeds, are approximately 20-50 pounds (9.07-22.68 kilograms) and large breeds, like the popular Labrador retriever and boxer, are usually considered on average to be greater than 50 pounds (22.68 kilograms). The average lifespan for medium and large breeds is approximately 10-13 years.

Giant Dog Breeds

Giant dog breeds are usually considered to be greater than 90 pounds (40.82 kilograms). The average lifespan for a giant breed, such as the regal Great Dane, is unfortunately only 6-8 years, but some have lived to be 11-12 years old or older.

Further, mixed-breed dogs tend to live about 1.2 years longer on average than same-sized purebred dogs.

The current record for the longest-living dog based on Guinness World Records is held by a medium breed dog born in Australia in 1910, an Australian cattle dog named Bluey, who lived for 29 years and 5 months.

How Can Pet Parents Help Their Dogs Live Longer?

There are many things that pet parents can do to help their companion live a longer life, no matter what size or breed they have. The following can keep your pet happy and healthy:

  • Provide routine wellness veterinary care: This includes regular physical examinations, appropriate vaccinations and other preventative health care measures, including heartworm and flea/tick preventatives, routine dental cleanings and blood work monitoring, as directed by a veterinarian. This routine care can help any dog live a longer life.
  • Spay and neuter: Dogs of any size or breed can benefit from spaying or neutering in order to live longer. It reduces the risk of certain reproductive cancers, prostate or uterine infections (which can be life-threatening) and potential traumas/injuries.
  • Maintain a healthy weight: Provide your furry friend with tons of daily exercise and feed them the appropriate amount of food. A recent study published in the Journal of Veterinary Internal Medicine showed that the lifespan of overweight dogs was shortened by up to 2.5 years compared to dogs at an appropriate weight. Maintaining an appropriate body weight places less stress on the joints and organ systems of the body.

Different breeds have certain health concerns that pet parents, along with their vet, should monitor. It's recommended that the pet parent learn about the characteristics and common health concerns of a particular breed or mixed-breed dog prior to adoption. This helps them to identify health concerns early on so that they can be addressed with the family's vet in a timely manner.

So, why do small dogs live longer? The short answer is that large dogs age more quickly than small dogs, but there's more to take into account. With routine vet care, exercise and lots of love, you can give your dog their best chance at living a longer, healthier life. And hopefully, with the continuing advances in veterinary care and nutrition, there will be a day in the future where we don't have to ask questions like "why do small dogs live longer than big dogs" anymore.

Dr. Jessica Seid Dr. Jessica Seid

Jessica Seid is an emergency veterinarian practicing in the New England area. She is a graduate of the North Carolina State College of Veterinary Medicine and has been in the field for more than a decade. When she's not helping patients, she enjoys spending time with her husband, daughter and French bulldog.

Related articles

Common Health Concerns to Look for in Puppies

Watch out for these 6 common health issues that puppies may develop in their first year of life. Learn all the symptoms so you can provide the best care.

Excessive Thirst in Dogs: Common Causes & When to See the Vet

Discover the many conditions that cause excessive thirst in dogs, from simple dehydration to more serious issues, and learn when you should visit the vet.

Can Dogs Eat Pumpkin?

Can Dogs Eat Pumpkin?

Why Are Dogs Scared of Vacuums?

Discover why your dog is afraid of the vacuum cleaner, how you can help them get used to it and overcome their fear.

Is it Safe to Feed My Dog a Banana?

Are bananas good or bad for dogs? Find out if it's safe too feed him a banana treat and what to do if he's eaten a whole one, peel and all.

Helping Your Dog Deal With Allergic Dermatitis & Skin Irritants

Discover seven common dog skin diseases — including causes, symptoms, and treatment — to stay educated about your dog's health.

Cataracts in Dogs: Symptoms, Appearance & Treatments

Learn everything you need to know about cataracts in dogs, including common symptoms of the condition, breeds most at risk, and how they can be treated.

Understanding Blastomycosis in Dogs

Learn important information on blastomycosis in dogs, including how its transmitted, common symptoms, treatment options & geographic considerations.

Canine Influenza Vaccine: What You Need to Know

While canine influenza is a newer condition, it can be troublesome for your pup. Learn about dog flu symptoms & which types of dogs should get vaccinated.

No Matter What Kind of Trip, This Dog Travel Checklist Can Help.

Whether you're taking your dog on a road trip, camping, or flying with him, use these helpful travel checklists to make sure you pack everything he needs.

Can Your Dog Smile At You?

It may look like your dog is grinning, but can dogs smile for real? Learn about their facial expressions & whether their face can actually show happiness.

Teaching an Old Dog New Tricks: A Guide for Senior Training

Is teaching an old dog new tricks really impossible? Discover the truth about this cliche and learn tips for successfully training your senior dog.

Why Do Dogs Need to Pee on Everything?

Are you curious why your dog feels the need to pee on everything? Learn what dog marking is, why dogs do it, and what you can do to reduce this behavior.

Clipping Dog Nails for Puppy Pedicures

Learn the basics for safely trimming your dog's nails at home, including tools you'll need and the technique for making trimming painless and easy.

Dogs and Ticks: Protecting Your Pup

Everything you need to know about dogs & ticks: identifying different types of ticks, what diseases they can cause and how to prevent future tick bites.

Puppy Day Care: Is It a Good Fit?

What should you look for when deciding on a dog day care? Learn tips for what to look for in a day care and how to prepare your pup for his first day.

Hill's Puppy Food: Quality Ingredients for Health & Nutrition

Learn about Hill's puppy food and the nutritional benefit & high quality ingredients that it contains for your pup.

Does My Dog Like to be Petted?

Does your dog really like to be petted? Learn the best spots to pet a dog, especially for new puppy owners, as well as areas to avoid when petting.

Tips for Socializing an Older Dog

Socializing an older dog is usually more challenging than socializing a puppy. Learn how to overcome the challenges to safely socialize an adult dog.

Hip Dysplasia in Dogs: Causes, Symptoms, & Treatment

Learn all about hip dysplasia in dogs, including causes & symptoms of the disease, most susceptible breeds, diagnosis and treatment options.