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How Old is My Adopted Dog?

Determining Your Dog’s Age

If you have decided to adopt a dog from an animal shelter or rescue GOOD FOR YOU! If you have already adopted or acquired your dog as a stray or from a friend THAT’S GREAT TOO!

Chances are, you know the approximate age of your adopted dog based on what you were told when you got him, but it is often difficult even for a veterinarian to tell the exact age of your pup. We can make an educated guess based on a few factors like teeth and fur color. You know your dog better than anyone. Learn the canine signs of aging and it will help you make more appropriate choices in the type of care you give your dog.

Chances are, you know the approximate age of your adopted dog based on what you were told when you got him, but it is often difficult even for a veterinarian to tell the exact age of your pup. If you are planning a trip to the animal shelter, you can take along these tips if age is a factor in picking out your new best pal.

First let’s talk a little about Aging Profiles of Dogs. Smaller dogs can live up to 16 years, medium sized dogs 10 to 14 years and large dogs like Great Dane size typically live 7 to 8 years. Large breed dogs stay “puppylike” for 24 months or more, compared to the usual 12 to 15 months for medium and small dogs.

Puppies: It is easier to tell how old a puppy is than an older dog based on their baby teeth:

  • At one month of age, milk teeth start pushing through the gums
  • Permanent Canine teeth come in around 5 months of age
  • The last permanent teeth to come in will be the back molars, those come in between 5 and 7 months of age

Ridges and Unevenness on the Front Teeth: At about 1 year of age, a dog will have ridges or bumps along the tops of their 4 front incisors, top and bottom jaw. Front incisors are the teeth that your dog uses for that nibbling type of grooming. As he ages, the bumps will wear down. At 3 to 4 years of age, the ridges should be halfway worn away and at about 7 years of age, the tops of these incisors should be completely smooth.

Tartar Buildup: Tartar generally starts to form around the teeth at about 4 years of age and gets darker and thicker the older your dog gets.

Just like with people, tooth condition depends on genetics and dental care or lack of care. Tooth condition is not an exact indication of age, just a guide.

Fur: Fur color is not a great way to gauge age. Fur around the muzzle or under the chin can start turning grey as early as 2 years old. Premature greying in dogs does exist. Stress is considered a factor, and dogs that had a rougher start in life may go grey earlier. Genetics are mainly responsible for when a dog goes grey, just like in people.

If you notice greying everywhere, like on the chest and face, behind the legs, ears and on the paws, your dog may be approaching senior status.

At what age is my dog considered a senior?

To answer this question most accurately, we have to refer to the Aging Profile factor. A dog is considered a senior in the last 25% of their expected lifespan.

  • A Great Dane has a life expectancy of 8 years, so they will be considered a senior at 6 years old
  • A Chihuahua has a life expectancy of 16 years, so they will be considered a senior at 12 years old

Young Senior Dog Indicators:

  • Senior dogs start developing lumps on their bodies called lipomas - these are fatty lumps and usually nothing to worry about
  • General slowing down and tiring out quicker after play
  • Behavioral changes: some not so great like new found fear of thunderstorms, others can be positive like attentiveness and patience
  • Muscle tone tends to decrease in senior dogs

Super Senior Dog Indicators:

  • Having accidents: Physical examinations should always be done if a housebroken dog starts having accidents indoors. If your older female dog has gone incontinent, your veterinarian can prescribe medication for this, and for males there’s always the Belly Band!
  • Lenticular Sclerosis is a bluish grey haze that covers your dog’s eyes when they get older. It does not affect your dog’s vision, but will look cloudy to you. Your veterinarian should be able to tell you if your dog has this when he shines a light into them. Lenticular Sclerosis is different than Keratitis (cloudy eye), the latter being very serious with a host of signs that should indicate vet attention is necessary.

Every dog is an individual, and if you spend time with them and tune into them you can probably guess pretty accurately how old they are. If you are planning a trip to the animal shelter, you can take along these tips if age is a factor in picking out your new best pal.


The Michelson Found Animals Foundation's mission of saving pets and enriching lives is made possible by the generous contributions of Dr. Gary Michelson and Alya Michelson.

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