Why do small dogs live longer than large ones? Here's a simple scientific explanation.
Dogs aren't like the rest of the animal kingdom.
A basic rule throughout nature is that larger animals tend to live longer than smaller ones. Elephants saunter into their sixties and whales can cruise the ocean for centuries, whereas mice live about a year or two and the common house fly won’t make it past a month.
The major reasons for the discrepancy are slower metabolisms and reduced risks from predators. However, there is a disconnect when it comes to man’s best friend. On average, smaller dogs tend to outlive larger ones.
For instance, petite Chihuahuas can live up to 15 years, outliving their significantly larger counterparts, Great Danes, by a solid 8 years. What’s to account for the huge difference in lifespan?
Dogs diverge from the rest of the animal kingdom regarding longevity primarily because of how they mature as puppies.
According to Discover Magazine, larger breeds suffer from more physical ailments when they age because they expend more of their early resources for growth instead of maintaining their bodies. This can lead to more damage on the cellular level that doesn’t manifest until the dog has reached adulthood. This lowers a larger dog's defenses against cancer while also raising the possibility of DNA replication damage that can lead to cancer at a later age.
To put it simply: Larger dogs grow up fast, which leads to a faster decline.
"There's a body of robust theory in evolutionary biology—what we call 'life history theory' – about the way animals allocate their resources to different functions," evolutionary biologist Professor Mark Elgar of the University of Melbourne's School of Biosciences told Phys.org. "The bottom line is, there is no free lunch.”
"We conclude that large dogs die young mainly because they age quickly," Elgar says.
It appears that all that wear and tear on a large breed dog’s body as they rapidly grow can harm its health in the long run. A group of undergraduate students from Colgate University in New York found that as puppies, large breed dogs have significantly more free radicals in their cells, which can lead to damage that has long-lasting effects.
Free radicals steal parts from other molecules, which causes damage and can lead to aging and disease.
Being a dog lover is bittersweet because you know that you and your furry friend will have to say goodbye one day. I guess that’s what makes the time together so special. Your time together is finite, so it’s best to enjoy it together while you can.
The good news is that, as pet owners, if we take good care of our dogs, they can have the best chance of living a long and happy life. The American Kennel Club offers this list of tips to promote your dog’s longevity and quality of life:
- Feeding a healthy diet
- Helping maintain a healthy weight
- Encouraging breed- and age-appropriate physical and mental exercise
- Taking our dogs for annual veterinary checkups and vaccinations
- Providing preventive dental care
- Administering heartworm, flea and tick preventatives
- Keeping them safe from accidents
- Giving love and affection