why do small dogs live longer than big dogs

Researchers Are Studying the Lifespan Inequity of Large and Small Dogs When it comes to lifespan, researchers have found that size matters. Small dog owners can expect to enjoy several more years with their pets than the owners of large dogs. It doesn t seem to make much sense: generally speaking, large mammals, like elephants and whales, tend to live longer than small ones, like mice. So why, then, do small dogs have a longer average life span than the larger breeds? This phenomenon has baffled scientists for years and was recently the subject of a study published in The American Naturalist. According to the lead researcher, Cornelia Kraus, who is an evolutionary biologist at the University of G ttingen in Germany, large dogs age at an accelerated pace, and their lives seem to unwind in fast motion.

Scientists concluded that every 4. 4 pounds of body mass reduce a dog s life expectancy by about a month. The reason why is still unknown, though Kraus suggests that there are several possibilities, including that larger dogs may succumb to age-related illnesses sooner. Also, larger breeds grow from puppies to adults at an accelerated rate, and this may lead to a higher likelihood of abnormal cell growth and death from cancer. These findings are just the tip of the iceberg in our understanding of canine lifespans and what determines them.

Scientists plan future studies to better explain the link between growth and mortality.
б explains why small dogs tend to live longer than big dogs. For more from Dr. Ward, find him onб б or atб. б As a practicing veterinarian of over twenty years, IБve been nagged by an obvious and seemingly unanswerable question: why do small dogs live longer than large dogs? For years itБs been widely accepted and understood in the pet world that tiny teacup poodles will live ten or more years longer than aб. TheyБre both dogs, share the same basic DNA, eat the same types of foods, and live in similar homes.

Yet one breed lives up to three times longer. Why? New research sheds some light on this issue. In the April issue of the scientific journal БThe American Naturalist,Б biologists at GermanyБs University of Gцttingen explored the relationship between size of dog breeds and life expectancy. Researchers analyzed data on over 56,000 dogs representing 74 breeds that visited North American veterinary teaching hospitals. The scientists found that larger dogs appeared to age at a faster rate than smaller dogs. Interestingly, the research concluded that every increase in 4. 4 pounds (2 kg) reduces life expectancy by approximately one month. б Okay, so my observations on small dogs living longer than big dogs were correct.

But why? That has yet to be definitively determined. Lead researcher Cornelia Kraus has been quoted saying that larger dogsБ lives Бseem to unwind in fast motion. Б Her research found that bigger breeds died more often from cancer than their tinier canine cousins. Kraus speculates that because large breeds grow faster and age quicker than small breeds, that abnormal cell growth found in cancers would be more likely. Another possibility is that larger dogs start aging at an earlier age, thus developing age-related diseases earlier. Kraus also postulated that larger dogs may simply live riskier or more dangerous lifestyles than dogs carried in handbags, thus leading to earlier mortality. б When Kraus and her colleagues plotted each of these three possibilities with the data, she found that the Бfaster agingБ hypothesis was most consistent with her findings. б My own suspicion is that in addition to accelerated cell division and growth, researchers will also discover more genetic abnormalities in large breeds due to fewer breeding pairs and smaller geographic distributions.

I also think theyБll find differences in key hormones such as IGF-1 or insulin-like growth factor 1, something scientists