At six months he was the dog everyone commented on. Walked beautifully, came when called, settled in the pub. At ten months you are standing in a field shouting a name he clearly recognises and is choosing to ignore, attached to a lead he is towing you down the street by, and you are quietly wondering whether you got something badly wrong.
You almost certainly didn’t. But the advice you are about to be given, “don’t worry, he’ll grow out of it”, is only half true, and the half that isn’t matters a great deal. There is good data on which adolescent problems resolve by themselves and which ones get worse if you wait.
The short version
- Most adolescent behaviour problems are a hump. They rise from six months, peak around twelve, and fall back by eighteen.
- Pulling on the lead, barking, jumping up, recall failures, chewing and toileting accidents all follow that curve in a UK cohort of over 1,700 young dogs.
- Three do not. Fear, threatening behaviour and reactivity keep climbing through to eighteen months rather than settling.
- So “he’ll grow out of it” is sound advice for a dog who pulls, and poor advice for a dog who has started lunging at other dogs.
- Research also shows adolescent dogs ignore their own owner specifically, while responding better to strangers. It is not a reflection of your training.
On this page
You didn’t break him
The most useful finding on adolescent dogs is also the strangest. Researchers at Newcastle University, publishing in Biology Letters, worked with 69 dogs and then a larger group of 285 Labradors, Golden Retrievers and German Shepherds. They found the odds of a dog repeatedly ignoring a sit cue from its own caregiver were higher at eight months than at five. Over the same period, the same dogs got better at responding to a stranger.
Read that again. The dog has not forgotten the cue. He has not lost his training. He is specifically less responsive to you, at a specific age, in a way that resolves. It is the closest thing dog behaviour has to a teenager rolling their eyes at a parent while being perfectly polite to a teacher.
The hump, in numbers
A UK and Ireland cohort study followed puppies through their first eighteen months, surveying owners at 6, 9, 12, 15 and 18 months, with 1,718 responses at the first point. Owners reported which unwanted behaviours their dog was showing. The pattern across most behaviours is the same shape.
| Behaviour | 6 months | 12 months | 18 months | Shape |
|---|---|---|---|---|
| Barking | 7.9% | 13.4% | 10.5% | Peaks, then falls |
| Jumping up | 5.2% | 7.4% | 5.6% | Peaks, then falls |
| Pulling on the lead | 3.8% | 6.6% | 3.4% | Peaks, then falls |
| Recall failures | 3.3% | 6.6% | 2.8% | Peaks, then falls |
| Destructive behaviour | 3.1% | 3.3% | 1.3% | Falls |
| Toileting accidents | 2.3% | 1.4% | 0.7% | Falls steadily |
If your dog is somewhere between nine and fifteen months and everything seems to have fallen apart at once, that is not a coincidence and it is not your training collapsing. It is the top of the curve. Lead pulling nearly halves between twelve and eighteen months without anyone doing anything clever.
Recall is the one most owners panic about, and we went into it separately in why your dog listens at home and ignores you outside.
The three that don’t fix themselves
Here is the part the reassuring articles leave out. In the same dataset, three categories move in the opposite direction.
| Behaviour | 6 months | 12 months | 18 months | Shape |
|---|---|---|---|---|
| Displaying fear | 1.8% | 3.9% | 3.2% | Roughly doubles and stays up |
| Threatening behaviour | 0.9% | 2.0% | 3.4% | Keeps rising |
| Reactive behaviour | 0.5% | 1.1% | 1.9% | Keeps rising |
These are also the behaviours where owners are most likely to be told to wait, because they are less common overall. Under 4% of dogs at any age is easy to dismiss. But the direction of travel, not the size of the number, is what should decide whether you get help.
The trap most owners fall into
Adolescence is the point at which a lot of people lose patience with reward-based training and start looking at corrections, prong collars and e-collars. The dog is bigger, the failures are more embarrassing, and “he knows what he’s doing” feels true.
A 2020 study in PLOS ONE assessed 92 companion dogs across seven training schools. Dogs from the high-aversive schools showed more stress-related behaviours during training, were more often in tense and low behavioural states, panted more, and had higher post-training rises in cortisol than reward-trained dogs. In a follow-up task with 79 dogs, they were also more pessimistic in a cognitive bias test, a difference that showed up outside the training context entirely.
Set the welfare argument aside for a moment. Look at the timing. The behaviours that are climbing during adolescence are fear, threat and reactivity. Adding stress and pain to a dog in the window when those three are rising is working against yourself.
Riding out the hump
- Lower the difficulty, don’t lower the standard. Go back to quieter places and shorter distances. You are not retraining from scratch, you are letting him succeed while his brain catches up.
- Stop spending cues you can’t back up. Every ignored recall makes the word weaker. If you are not confident, go and get him.
- Pay better, not more often. The competition outdoors has got more interesting. Your rewards need to keep pace.
- Use equipment to manage while training catches up. A long line for recall, a well-fitted harness for pulling. Management is not cheating, it is preventing rehearsal.
- Protect sleep. Adolescent dogs are frequently overtired rather than under-exercised, and the symptoms look identical. We covered that pattern in puppies in the puppy witching hour.
- Keep going for a season, not a fortnight. The data says the curve turns between twelve and eighteen months. Most people quit at the peak.
Acting on the slope
If what you are seeing is fear, growling, lunging or reactivity rather than ordinary teenage rudeness, the plan is different and the timing is urgent.
- Book a vet appointment first. New fear or aggression in a young dog can have a physical cause. Pain changes behaviour before it changes how a dog moves.
- Get qualified help early, not after six months of hoping. Look for someone who uses reward-based methods and holds an assessed qualification rather than a self-issued title.
- Stop the rehearsals. Every lunge on a walk practises the behaviour. Change your route, your times, your distance. Avoiding the trigger is a legitimate part of treatment, not a failure.
- Write down what happens. Trigger, distance, your dog’s reaction, how long to recover. This is the single most useful thing you can bring to a behaviourist.
- Do not punish the growl. A growl is information. Suppress it and you get a dog who skips the warning.
If the problem is that he plants himself and refuses to move rather than reacting outwards, that is a different picture again, covered in why a puppy plants himself and won’t walk on the lead.
Common questions
When does dog adolescence actually start and end?
Roughly six to eighteen months, varying with size and breed. The behavioural peak in the cohort data sits around twelve months, with most of the common problems back near their starting level by eighteen.
He was perfect and now he ignores everything. Did I train him wrong?
Probably not. The Newcastle research found reduced responsiveness was specific to the owner and improved for strangers over the same months, which points to development rather than training failure.
Should I stop training until he grows out of it?
No. Reduce difficulty so he can succeed, but keep going. Stopping means eighteen months of rehearsing the wrong things, and the habits outlast the hormones.
Will neutering fix it?
It is not a training solution, and for fear-based or reactive behaviour the evidence does not support it as a fix. It is a separate decision to discuss with your vet on its own merits.
How do I tell ordinary teenage rudeness from something more serious?
Ask what the behaviour is made of. Excitement, distraction and poor impulse control are the hump. Fear, avoidance, growling, lunging and stiffness are the slope. If you are seeing the second group, do not wait it out.
The bottom line
Most of what makes a ten-month-old dog exhausting is a curve that comes back down on its own, and the evidence says you should hold your nerve, keep training, and stop reaching for harsher tools. But fear, threat and reactivity are not on that curve. They are still climbing at eighteen months. Knowing which of the two you are looking at is the most important judgement you will make this year.
Sources
- Asher L, et al. Biology Letters, 2020. Adolescent-phase conflict behaviour; reduced responsiveness to the caregiver but not to a stranger.
- Generation Pup cohort, Owner-Perceived Undesirable Behaviours in Young Dogs and Changes with Age, 2025. Prevalence of nineteen behaviours at 6 to 18 months.
- Vieira de Castro AC, et al. PLOS ONE, 2020. Welfare outcomes of aversive versus reward-based training in 92 companion dogs.
