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 Chihuahua and a Great Dane
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
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- The oldest whales in the ocean were alive before 'Moby-Dick' and have the harpoons to prove it - Upworthy ›



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An Irish woman went to the doctor for a routine eye exam. She left with bright neon green eyes.
It's not easy seeing green.
Did she get superpowers?
Going to the eye doctor can be a hassle and a pain. It's not just the routine issues and inconveniences that come along when making a doctor appointment, but sometimes the various devices being used to check your eyes' health feel invasive and uncomfortable. But at least at the end of the appointment, most of us don't look like we're turning into The Incredible Hulk. That wasn't the case for one Irish woman.
Photographer Margerita B. Wargola was just going in for a routine eye exam at the hospital but ended up leaving with her eyes a shocking, bright neon green.
At the doctor's office, the nurse practitioner was prepping Wargola for a test with a machine that Wargola had experienced before. Before the test started, Wargola presumed the nurse had dropped some saline into her eyes, as they were feeling dry. After she blinked, everything went yellow.
Wargola and the nurse initially panicked. Neither knew what was going on as Wargola suddenly had yellow vision and radioactive-looking green eyes. After the initial shock, both realized the issue: the nurse forgot to ask Wargola to remove her contact lenses before putting contrast drops in her eyes for the exam. Wargola and the nurse quickly removed the lenses from her eyes and washed them thoroughly with saline. Fortunately, Wargola's eyes were unharmed. Unfortunately, her contacts were permanently stained and she didn't bring a spare pair.
- YouTube youtube.com
Since she has poor vision, Wargola was forced to drive herself home after the eye exam wearing the neon-green contact lenses that make her look like a member of the Green Lantern Corps. She couldn't help but laugh at her predicament and recorded a video explaining it all on social media. Since then, her video has sparked a couple Reddit threads and collected a bunch of comments on Instagram:
“But the REAL question is: do you now have X-Ray vision?”
“You can just say you're a superhero.”
“I would make a few stops on the way home just to freak some people out!”
“I would have lived it up! Grab a coffee, do grocery shopping, walk around a shopping center.”
“This one would pair well with that girl who ate something with turmeric with her invisalign on and walked around Paris smiling at people with seemingly BRIGHT YELLOW TEETH.”
“I would save those for fancy special occasions! WOW!”
“Every time I'd stop I'd turn slowly and stare at the person in the car next to me.”
“Keep them. Tell people what to do. They’ll do your bidding.”
In a follow-up Instagram video, Wargola showed her followers that she was safe at home with normal eyes, showing that the damaged contact lenses were so stained that they turned the saline solution in her contacts case into a bright Gatorade yellow. She wasn't mad at the nurse and, in fact, plans on keeping the lenses to wear on St. Patrick's Day or some other special occasion.
While no harm was done and a good laugh was had, it's still best for doctors, nurses, and patients alike to double-check and ask or tell if contact lenses are being worn before each eye test. If not, there might be more than ultra-green eyes to worry about.