For Life Span, a Dog’s Size Matters

Large Dogs Seem to Age at a Fast Pace

Research has yet to explain the relationship between body mass and a dog’s lifespan.

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 large breeds?

This phenomenon has baffled scientists for years and was the subject of a study published in The American Naturalist.

Large dogs age at an accelerated pace, and “their lives seem to unwind in fast motion,” according to lead researcher Cornelia Kraus, an evolutionary biologist at the University of Göttingen in Germany.

Scientists concluded that every 4.4 pounds of body mass reduced a dog’s life expectancy by about a month. The reason why is still unknown, though Kraus hypothesized several possibilities, including that larger dogs may succumb to age-related illnesses sooner and that the accelerated growth of large dogs may lead to a higher likelihood of abnormal cell growth and death from cancer.

Scientists plan future studies to better explain the link between growth and mortality.

The original version of this article appeared in “Paw Prints” in AKC Family Dog.