It's complicated! And it's difficult to give a definitive answer. However, we can take a look at veterinary studies analysing different populations in different countries to at least draw some high level conclusions.
Dogs go through various life stages as they grow from playful puppies to mature adults and finally into their senior years. These stages include puppyhood, adolescence, adulthood, senior and geriatric. The timing of these life stages is influenced by size, breed, genetics and lifestyle.
Fortunately, over the past few decades, average life expectancy for dogs has steadily increased. Studies show dogs are living longer now compared to some years ago. This rise is likely due to improvements in veterinary medicine, preventative care, nutrition, and other advances in canine health and wellbeing. Dog parents also have greater access to information and resources for optimal care of their pets.
While many factors influence lifespan, size impacts it the most. A dog’s weight is more predictive of lifespan than either height, breed, or breed group. In variation of body size, dogs far surpass all other domestic animals, with at least a 40-fold difference between the largest and smallest breeds. Among species, larger animals tend to live longer than smaller ones, however, the opposite is usually true between individuals of the same species.
Smaller dogs tend to live significantly longer than larger dogs across all breeds. Large dogs (above 50 kg) like Great Danes and Bouviers generally live for 6-8 years, while small dogs (below 10 kg) like Chihuahuas and Toy Poodles can reach 14-16 years.
Breed matters too. Certain ancestral breed groups, like mountain dogs, have lifespans shorter by 3-4 years. Some breeds are more prone to some diseases like cancers and heart problems that cut their lives short.
The decision to spay or neuter makes a big difference. Intact females tend to live shorter lives by 1-2 years on average, likely due to pregnancy complications and mammary cancers. However, spayed females live the longest of all by 1-2 years over intact females. For males, neutering brings a smaller longevity boost of about 6 months compared to intact males. Those spayed or neutered under 1 year of age gain the most longevity benefits. However, the optimal age for gonadectomy is still debated.
Genetics also play a key role. Mixed breed dogs live around 1-2 years longer than purebreds on average, likely due to hybrid vigor and reduced inbreeding. Across purebreds, breeds with lower inbreeding coefficients and higher genetic diversity can live up to 1 year longer.
Large breeds tend to have higher inbreeding, likely due to breeding practices involving fewer reproducing females. Variation in inbreeding between breeds does not appear to impact lifespan as much as size itself. However, inbreeding within breeds does reduce lifespan.
Lifestyle also influences lifespan. Obesity in pets is a condition of particular interest. It is the most common nutritional disorder in companion animals, and obese dogs have a reduced lifespan compared with dogs of normal body condition. Overweight dogs have lifespans shorter by 1-2 years compared to lean, ideal body condition. But underweight also foreshadows illness and reduces longevity so maintaining optimal weight is necessary for a long and healthy life.
Dogs receiving attentive preventive veterinary care live up to 1 year longer by catching problems early. More frequent dental cleanings add years by reducing bacteria and infection risk.
Higher household income is linked to better health, likely through increased veterinary care. However, income also associates with more diagnosed diseases, potentially reflecting greater diagnostic opportunities that catch issues before they impact lifespan.
Socialisation and mental stimulation are also important for behavioural and cognitive health. Social isolation is linked to higher mortality risk and lower overall wellbeing. Dogs living with other pets experience health benefits comparable to social integration for people. Dogs in unstable neighbourhoods with high turnover suffer mobility declines very similar to low socioeconomic status human populations.
Allowing dogs to roam freely decreases lifespan by 1-2 years from accidents and infectious diseases like parvo virus. Supervision maintains safety and health. Providing a secure loving home environment contributes greatly to longer, healthier lives.
While genetics and breed traits play a role, lifestyle and preventive care choices also greatly impact how long dogs live. Understanding these factors helps us make informed decisions to nurture our four-legged friends. When it comes to canine longevity, proactive care and love are key.
This post is part of my deep dive into the topic of longevity for dogs to understand how can we help our best friends live longer and healthier lives. This is a complex topic and any attempt to compress it into a digestible post may look like an oversimplification. If you want to go deeper, below you can find some papers that helped me write this post.
- 2019 AAHA Canine Life Stage Guidelines
- Risk Factors Associated with Lifespan in Pet Dogs Evaluated in Primary Care Veterinary Hospitals
- Lifespan of companion dogs seen in three independent primary care veterinary clinics in the United States
- Is free-roaming a key factor determining lifespan? An epidemiological study on the life expectancy of Turkish companion dogs
- Life expectancy tables for dogs and cats derived from clinical data
- Association between life span and body condition in neutered client-owned dogs
- Body size, inbreeding, and lifespan in domestic dogs
- How size and genetic diversity shape lifespan across breeds of purebred dogs
- The Size–Life Span Trade-Off Decomposed: Why Large Dogs Die Young
- Exploring mechanisms of sex differences in longevity: lifetime ovary exposure and exceptional longevity in dogs
- Reproductive Capability Is Associated with Lifespan and Cause of Death in Companion DogsLife tables of annual life expectancy and mortality for companion dogs in the United Kingdom
- Longevity and mortality in Kennel Club registered dog breeds in the UK in 2014
- Longevity and mortality of owned dogs in England
- Social determinants of health and disease in companion dogs: a cohort study from the Dog Aging Project
- Healthy, Active Aging for People and Dogs