"Dogs age" can be used synonymously with "canine years" or "dog years". These phrases refer to the common belief that one year of a dog's life is equivalent to seven human years. However, this perception is somewhat inaccurate as different dog breeds age at different rates. Another alternative is "puppyhood" which refers to the period of a dog's life when it is still young and playful. As a dog reaches maturity, "adulthood" can be used to describe this stage of life. Finally, as a dog enters its later years, "senior dog" or "geriatric dog" can be used to describe its age.