At what age does an old dog lose its teeth?

There's no 'normal' age for that. Once the teeth have come through, a dog keeps its 42 teeth for life. A tooth that loosens or falls out in an adult or a senior is almost never down to age: it's most often gum disease, painful but treatable, to be shown to the vet.

Spotting the signs of ageing in my dog

Caring for my ageing dogPart of · Caring for my ageing dog

Spotting the signs of ageing in my dog

Q: How long does a dog live?

It depends mostly on size : smaller builds age more slowly and can reach 15-16 years, whereas large and giant dogs live less long. That's also why a large dog is a 'senior' from 6-7 years while a small one is closer to 9-10 (AAHA 2023 consensus).

Q: Why does my old dog pace in circles?

In an old dog, circling, wandering or getting lost in a familiar room, especially in the evening and at night, often points to cognitive decline (the canine equivalent of senile decline). It's neither silliness nor a whim. Before blaming it all on age, the vet first rules out pain, a full bladder or failing sight, and the earlier you act, the better you can support him.

Q: At what age is a dog considered a senior?

Mostly according to size: a large or very large dog is a senior from 6-7 years, a small one closer to 9-10, because smaller builds age more slowly (AAHA 2023 consensus). The point isn't the exact number, but to bring the check-ups closer together as he enters the last quarter of his life.

Q: My old dog sleeps a lot, is that normal?

Often yes: an adult already sleeps 12 to 14 hours out of 24, and a senior edges towards the top of that range. What should raise the alarm is a clear change : he suddenly sleeps much more and stays listless, absent when he wakes, or he sleeps badly and wanders at night. Then, have him examined.

Q: My old dog drinks and urinates a lot, is it serious?

It's the senior's red flag : drinking markedly more and urinating more can signal a kidney problem, diabetes or Cushing's. You never restrict his water to sort it out. Note how long it's been going on, put a number on it if you can, and see the vet fairly soon.

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“He's old” is not a diagnosis

Age makes certain illnesses more likely, and a dog often hides that he is unwell. The right reflex is to ask yourself whether this is simply the body gently slowing down, or a sign that should take you to the vet, rather than stopping at “he's old”.

A dog becomes “senior” mainly according to his size: a big dog is one from 6-7 years old, a small one closer to 9-10 years, because small builds age more slowly.

The signs of passing time

Not all changes are equal: some come with age and are nothing serious, others call for a vet's opinion. What matters is the sign, not the dog's age.

The harmless signs: the body slowing down

A greying muzzleThe coat turns white on the muzzle and eyebrows: nothing serious, and it doesn't hurt.

A bit more sleepAn adult already sleeps 12 to 14 hours out of 24; a senior tends closer to 14 hours.

Shorter walksHe has less stamina than at 3 years old: shorten the walk, but keep going out.

A steadier temperamentHe often becomes calmer; as long as he stays curious and keen on his food, all is well.

The signs that deserve a vet's opinion

Stiffness, limping, stairs he avoidsIt is often arthritis (worn joints), and it isn't a life sentence: it treats well, and he gets his spark back.

He drinks and urinates much moreIt can come from the kidneys, from diabetes or from a hormonal illness (Cushing's). Tell your vet quickly.

A new lump under the skinIf you feel a lump appear, grow or change, show it to the vet, without piercing it.

Unintended weight lossIn an old dog, losing weight for no reason is never trivial. Take him to the vet, as it often hides something else.

He gets lost, paces in circles, is restless at nightIt can be cognitive decline, the equivalent of an ageing brain: the sooner you react, the better he is supported.

Bad breath, a loose toothIt is rarely a matter of age, but gum disease, which is painful and treats well.

He eats less, or not at allAn appetite that fades little by little counts as much as a sudden refusal: both often hide an illness. If he stops eating altogether, or if he vomits and stays low, call the vet quickly.

A sign can change meaning: if he sleeps more and stays limp, vacant when he wakes, it is no longer harmless, so show him to the vet.

What you can keep an eye on yourself

Between two visits, you are the one who sees your dog every day: nobody is better placed to spot what changes. Note it in a notebook or on your phone, it helps the vet compare from one visit to the next.

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An old dog is not a dog waiting for the end: he still learns, at any age. Since he burns less energy physically, keep his head busy: hide kibble around the house, teach him a trick, give him a toy to rummage in. He keeps himself occupied and tires himself out without straining his joints. The time spent with him counts for more than his performance.

AAHA — Senior Care Guidelines for Dogs and Cats (2023)
WSAVA Global Pain Council — Guidelines on chronic pain in dogs
Salvin et al. — Canine cognitive dysfunction: prevalence and under-diagnosis (2010)
Niemiec et al. (WSAVA) — Global Dental Guidelines (2020)
Merck/MSD Veterinary Manual — Dental Development of Dogs (dental formula: 42 adult teeth)

Going further

guideWorking out my dog's ageTurn your dog's age into concrete markers, so you know when he really enters his later years.Read the guide guideAssessing my dog's quality of lifeA simple grid to assess, day after day, whether his comfort of life is still good.Read the guide guideArthritis and mobility: keeping my dog comfortableStiffness, trouble jumping: what really helps, and it's free, a healthy weight.Read the guide guideAdapting daily life for an ageing dogRamps, non-slip mats, a warm bed: simple changes that make daily life easier.Read the guide guideCognitive decline (senility) in the older dogDisorientation, disturbed sleep: recognising senility to support your dog better.Read the guide guideVet check-ups for your senior dogThe right rhythm of visits and tests, to anticipate rather than react.Read the guide

Frequently asked questions

At what age does an old dog lose his teeth?

There is no “normal” age for that. Once teething is over, a dog keeps his 42 teeth for life. If a tooth becomes loose or falls out in an adult or a senior, it is almost never because of age, but most often because of gum disease, which is painful but treatable. Show it to the vet.

How long does a dog live?

It depends above all on size: small builds age more slowly and can reach 15-16 years, whereas large and giant dogs live appreciably less long. Breed, ideal weight and health follow-up also play a part.

Why does my old dog pace in circles?

If your dog paces in circles or gets lost in a room he knows well, especially in the evening and at night, that often suggests cognitive decline. It is neither stupidity nor a whim. Before putting it all down to age, the vet first rules out pain, a full bladder or failing eyesight. And the sooner you react, the better he is supported.

At what age is a dog considered a senior?

It depends first on his size: a large or very large dog becomes a senior around 6-7 years old, a small one closer to 9-10 years, because small builds age more slowly. The number matters less than the principle: he needs closer follow-up as soon as he enters the last quarter of his life expectancy. That is the definition of “senior” used by the AAHA (2023).

My old dog sleeps a lot, is that normal?

Most often yes: an adult dog already sleeps between 12 and 14 hours out of 24, and a senior tends closer to 14 hours. What should alert you is a clear change: he suddenly sleeps a lot more and stays limp, vacant when he wakes, or he sleeps badly and paces in circles at night. In that case, off to the vet.

My old dog drinks and urinates a lot, is it serious?

It can be. If he is drinking and urinating markedly more, take it seriously: it can signal kidney disease, diabetes, or Cushing's. Never restrict his water to deal with it. Note how long it has been going on, measure how much water he drinks if you can, and get advice fairly quickly.

My old dog isn't eating any more, what should I do?

Don't let it drag on. There is no official deadline beyond which you must consult, but a dog who hasn't touched his bowl for a day or two needs a vet's opinion, and sooner still if he is old. Don't wait for a total refusal: an appetite that fades little by little, over weeks, often reveals an underlying illness, such as kidney disease or a tumour. If he vomits, stays low, has a swollen belly or pale gums, get to the vet without delay.

Updated on July 11, 2026Sources

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