Reduced Life Span of Large Dogs
A new study on large and small breed dogs may explain why larger breeds generally have shorter life spans. It may be that rapid growth as puppies leads to overproduction of oxygen free radicals, which can have long-term effects and result in premature aging.
Read more on the new hypothesis for the shorter life span of large dogs in Science.
Learn more about the physiology of dogs in the Merck Veterinary Manual.