Figuring out your dog's age is tricky without a birth certificate. There is no surefire way to to determine his age without records, but you can get a rough estimate by examining his body and demeanor. Research his life expectancy according to his breed and size before you get started.
Examine your pet's teeth when the opportunity presents itself. If you are comfortable handling your dog at close quarters, gently lift his gums away with your fingers to get a closer look. If his teeth are white and clean, he's probably less than two years old. Canine teeth start to accumulate tartar and turn yellow after two years, and they usually have significant tartar after five. Older dogs often have a layer of tartar covering all their teeth by the time they are ten years old. At this point, most of the teeth are entirely yellow and brown.
The sharpness of your dog's teeth can also help you figure out his age. Teeth are sharp and pointy when they first come in, but even incisors start to wear down into more rounded tips after 4 or 5 years. Red, bleeding and discolored gums are signs of dental disease, which are commonplace in senior dogs. Dogs can start losing their teeth by 10 to 15 years of age. Even though teeth are one of the best indicators of your dog's age, keep in mind that the dog may have received dental care before you got him.
Signs of Seniority
Gray fur doesn't necessarily mean your dog is old, and not all senior dogs experience fur color changes. Your furry friend is considered a senior once he enters the final 25 percent of his expected life span, according to the Found Animals Foundation. Early signs of seniority in dogs includes the development of harmless lumps on his torso, decreased muscle tone and diminished stamina during exercise. Older senior dogs tend to struggle to get up after laying down due to joint pain. Many senior pups also have clouded or hazy-looking eyes. Some causes of ocular discoloration are purely cosmetic, but the cloudiness may also be related to a vision-impairing disorder like cataracts.
A Pomeranian celebrating his tenth birthday is actually more youthful than a six-year-old Great Dane. It's hard to judge a dog's age without knowing the expected life span of the breed, since tooth decay and signs of senior-hood arrive much sooner in some canines than others. Smaller breeds under about 40 pounds tend to live 15 to 20 years, although some medium-sized dogs can hit the double digits just as easily. Great Danes and some other larger breeds over 50 pounds are considered seniors at around 6 years, since they are only expected to live 8 or 9 years. Not all large dogs are short-lived though. For example, Doberman Pinschers are expected to live 15 years or longer despite an average adult weight of almost 80 pounds, according to America's Pet Registry.
Quentin Coleman has written for various publications, including All Pet News and Safe to Work Australia. He spent more tan 10 years nursing kittens, treating sick animals and domesticating semi-feral cats for a local animal shelter. He graduated from the University of Delaware with a bachelor's degree in journalism.