 Hi, I'm Warren Eckstein with the Pet Show Tip of the Day. The senior dog. You know, many similarities exist between the aging process in humans and the aging process in dogs. For instance, a sign of aging common in both is the graying of the hair around the head. In dogs, it's particularly apparent around the muzzle and the ears. Both older people and older dogs are likely to experience the stiffness associated with arthritis of the joints. And just as with older people, older dogs are prone to losing a portion or all of their eyesight and their hearing.