Aging in dogs varies from breed to breed, and affects the dog's health and physical ability. As with humans, advanced years often bring changes in a dog's ability to hear, see, and move about easily. Skin condition, appetite, and energy levels often degrade with geriatric age. Medical conditions such as cancer, kidney failure, arthritis, dementia, and joint conditions, and other signs of old age may appear.
The aging profile of dogs varies according to their adult size (often determined by their breed): smaller breeds have an average lifespan of 10-15 years, with some even exceeding 18 years in age; medium breeds typically live for 10 to 13 years; and giant dog breeds have the lowest minimum lifespan, with an overall average of 8 to 13 years. The latter reach maturity at a slightly older age than smaller breeds, with giant breeds reaching adulthood at around two years old compared to the norm of around 13–15 months for other breeds. The accelerated rate of growth required by the drastic change in size exhibited in giant breeds is speculated by scientists at the American Kennel Club to lead to a higher risk of abnormal cell growth and cancer.[1]