Recognising 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: 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.

7 min read

Growing old isn't an illness

Ageing isn't an illness: a healthy older dog can enjoy years of happy life (AAHA 2023 consensus). What makes it trickier is that old age makes certain illnesses more likely, and that a dog masks them out of a survival instinct. The right reflex is to tell a body that's gently slowing down apart from a sign that calls for an opinion. 'He's old' is never a diagnosis: at best, it's a hypothesis to confirm with the vet.

'Senior' depends mostly on size: a large dog counts as one from 6-7 years, a small one closer to 9-10, because smaller builds age more slowly (AAHA 2023 consensus).

The signs of the passing years

Not all changes are equal: some come with age and mean no harm, others call for a look from the vet. What matters is the line, not the age.

The harmless signs: a body slowing down

A greying muzzleThe coat whitens on the muzzle and eyebrows with age: it's cosmetic and painless.

A little more sleepAn adult already sleeps 12 to 14 hours out of 24; a senior edges towards the top of that range.

Shorter walksLess stamina than at 3: you shorten them, but you keep going out.

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

The signs that deserve a vet's opinion

Stiffness, limping, avoiding the stairsOften painful arthritis, not something to simply accept: it can be eased (a dog whose pain is relieved often 'grows younger').

A clear rise in thirst and urinationThe senior's red flag (kidney, diabetes, Cushing's): flag it quickly.

A new lump under the skinAny mass that appears, grows or changes should be shown to the vet, without piercing it.

Unintended weight lossNever trivial in an old dog: have it investigated.

Disorientation, wandering, day-night reversalCould be cognitive decline (CCD), which is managed all the better the earlier you act.

Bad breath, a loose toothNot 'age': almost always gum disease, painful but treatable.

The same sign can tip over: a dog that sleeps more AND stays listless, absent when it wakes, is no longer in the 'normal' zone and should be examined.

What you can keep an eye on yourself, calmly

Between two visits, you're the one who sees your dog every day: no one is better placed to spot what changes. A notebook or a note on your phone turns a hunch into a useful marker for the vet.

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An old dog isn't a dog whose end you're waiting for. Keep giving him something to think about: scent games around the house, little exercises, a trick taught gently with a marker word. The shared moment matters more than the performance.

AAHA — Senior Care Guidelines for Dogs and Cats (2023)
WSAVA Global Pain Council — Recommendations 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)

To go further

guideWorking Out Your Dog's Age (and What It Really Means)Turn your dog's age into real milestones, so you know when the senior years truly begin.Read the guide guideAssessing your dog's quality of lifeA simple checklist to assess, day by day, whether their comfort and quality of life still hold up.Read the guide guideArthritis and mobility: keeping my dog comfortableStiffness, trouble jumping: what really helps, and it's free, keeping them at a healthy weight.Read the guide guideAdapting daily life for an ageing dogRamps, non-slip mats, a warm bed: simple changes that ease everyday life.Read the guide guideCognitive decline (senility) in the senior dogDisorientation, disrupted sleep: spotting cognitive decline so you can support them better.Read the guide guideVeterinary care for your senior dogThe right pace of check-ups and tests, so you stay ahead of problems instead of reacting to them.Read the guide

Frequently asked questions

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.

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).

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.

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.

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.

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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