Small dogs live longer than large dogs.

[bluemingidiot]

A study found that larger dogs are prone to cancer, bone-related diseases, gastrointestinal problems, neurological and endocrine conditions, ears, nose, and throat issues, and infectious diseases.

It found that smaller dogs are more likely to suffer from ocular, cardiac, and respiratory issues, along with liver or pancreatic diseases.

Part of the explanation may be that a larger percentage of big dogs live outside in harsher and less hygienic situations.  Additionally, since they eat more, they may get cheaper, less wholesome food.

[vickilynn]

Cavalier King Charles Spaniels are a small dog exception. They don’t have a very long life span. So many genetic diseases. I’ve been lucky with my Jenny. She’s almost 10 now. Last vet visit, though, they heard the dreaded heart murmur, indicating MVD. Hope I have a couple more years with her yet.

[Woodpecker]

This has always happened with our dogs. Our black golden retriever & ? The owner never knew who the father was, but Cooper looked like a really big black Lab, with sort of a Great Dane look, weighed 95lbs. He died at 6 years old, unknown reasons. Our Boxer Jade was also a big girl, 90 lbs & died when she was laying on the deck at 6 years old, too. Unknown reason also.

My daughters Jack Russsell Terrier lived until 15 years old. We had to put him down as he couldn’t get up to walk. Vet took tests, she thought he had cancer. That was a terribly hard, sad day.

[bluemingidiot]

In a separate study of 584,000 dogs in Great Britain, Large dog breeds and breeds with flattened faces had shorter average life spans than smaller ones and those with elongated snouts.  Female dogs also lived slightly longer than male ones.

[countrymom22]

Mixed breed dogs also seem to live longer and be healthier.