Ask the Vet: Do Smaller Dogs Live Longer?

Does the size of your dog affect how long he will live?


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Question: Is it true that small dogs live longer than large dogs? And if so, why?

Answer: Yes, it’s true, though no one is completely sure why. Generally speaking, large mammals live longer than small mammals. For example, elephants live much longer than mice. However, within a given species, the smaller animals generally live longer than the larger ones.

Nowhere is it more pronounced than with dogs, probably because their size range — from the massive mastiff to the tiny Chihuahua — is so extreme. Research has found that large dogs live about 5 to 8 years, while small dogs average 10 to 14 years. A study of over 50,000 dogs comprising 74 breeds that examined size, age at death, and cause of death revealed that large dogs actually age faster than small dogs. More research is being done to better understand why.

In the meantime, enjoy every moment with each of your dogs, regardless of their expected longevity.

Ask the Vet is written by veterinarian Lee Pickett, VMD. Send questions to [email protected] and read more at

This article is featured in the November/December 2022 issue of The Saturday Evening Post. Subscribe to the magazine for more art, inspiring stories, fiction, humor, and features from our archives.

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