Decoding Your Dog’s Age: What to Look For

It’s common to be unsure about the age of your rescue dog. Fortunately, there are some ways to determine how old he really is.
By: Caitlin Ultimo
Decoding your dog's age

It’s not uncommon for pet parents to be unsure of their dog’s age. When pets are found through shelters and foster homes, sometimes—due to circumstances beyond their control—the rescue group won’t have a full background about the dog. “In my practice, we commonly see rescued pets and we are unsure of their age,” says Stephanie Liff DVM and owner of Pure Paws Veterinary Care of Brooklyn, NY. You may have been given an age or age range for your pet, but still wonder if that estimation is accurate.

How Old is My Dog?

Knowing your dog’s age can give you a better idea of his overall health, but more often you may just want a little insight into his life before he made it to you and his forever home.

“Experienced veterinarians can quite often decipher approximate ages with a given history, but in a shelter situation where little is known about the patient’s past, aging becomes more variable when you extend beyond 2 to 3 years,” says Danel Grimmett DVM, of Sunset Veterinarian Clinic. You may not ever be able to definitively determine your dog’s exact age (typically there is a margin of roughly two years) but you can formulate a better guess by considering a few of your dog’s current characteristics.

How to Tell How Old a Dog Is

While it’s unlikely that you’ll be able to pinpoint your dog’s exact age, there are some physical and behavioral signs that can help you come up with a good ballpark. Try the following suggestions for figuring out your dog’s age.

Check their teeth. After four months of age, your dog’s permanent or adult incisors, canines and premolars should be erupting. By six months, the baby teeth should be gone. If your dog still has a few baby teeth he is still a puppy and you can guess he’s younger than six-months-old. Beyond that, though, without knowing the birthdate, it can be difficult to use teeth as the defining factor.  “Some younger pets will have unhealthy teeth due to poor husbandry and nutrition and so it can be difficult to determine age based on the cleanliness of the adult teeth,” says Liff.  

Observe their eyes. “We often see age related changes in the eyes such as iris atrophy, cataract formation or lenticular sclerosis,” says Liff. However, these changes are not present in every older animal and there is not a specific age at which you can expect to see these changes.  Cataracts, for example, can develop in young dogs due to congenital disease, ocular trauma or other metabolic diseases like diabetes.  

Look for grey hair. White or grey hairs around your dog’s face and muzzle can help in figuring out their age. Typically, greying of the muzzle starts around the age of five, but some dogs may go grey as early as two-years-old. Premature greying may simply be a part of your dog’s genetic makeup, however some believe environmental and cellular stress may also play a role.

Consider the breed. When trying to determine your dog’s age it’s smart to keep in mind the varying life expectancy for the size and type of pet being assessed. “It would be quite extraordinary to meet a Great Dane who is 13-years-old, but not so unusual to meet a Chihuahua of that age,” explains Grimmett.

Look for signs of arthritis. If your dog seems to be experiencing joint pain or stiffness he may have arthritis. Arthritis is another finding that usually is associated with advanced age, but again, it can be difficult to conclusively determine your dog’s age range solely based on whether he has or doesn’t have arthritis symptoms. “In pets with congenital malformations, like hip or elbow dysplasia, or a previous history of trauma, you may note arthritis at a very young age,” shares Liff.

Have a vet complete a blood profile. Blood work that examines your pet’s kidney, liver, pancreas and thyroid function may help identify your dog’s age range. Senior dogs may be more susceptible to issues or diseases that would show in the blood test, while a younger dog, would most likely not have irregularities.

“In the end, age is just a number when you extend beyond the puppy stage,” shares Grimmett. “Your dog’s overall health status and personality should play a larger role in determining placement into a home.”