Border Collie Adolescence

Border collie adolescence
Border collie adolescence is the cause of over 90% of my behaviour consultations, which tells you how challenging this part of raising a collie can be! Their problem behaviours range from aggression to owners, strangers or other dogs, to shadow chasing, chasing vehicles, lack of recall, pulling on the lead or sound fears and phobias, to name just a few. And adolescence is a dangerous time for dogs. Research has shown that the biggest cause of death in dogs aged 1-3 years is being put to sleep due to behaviour problems or being involved in a road traffic accident (often due to lack of recall)?

So what’s going on?

In this article I’m going to take a deep dive into border collie adolescence to explain exactly what’s happening inside our collies when they hit the dreaded teenage phase.

They’re still puppies!

adolescent border collie

We all tend to forget that adolescent dogs are still puppies! They look grown up and we’ve already taught them all of these great behaviours and they’ve generally been doing well, so we expect a lot of them. However, our temperamental teenagers are actually still inexperienced, vulnerable puppies. They still need a lot of sleep, they still can’t have too much exercise, they still need protecting and they’re not old enough to know better.

So what is border collie adolescence?

Adolescence is a transient event that precedes and outlasts puberty. The onset varies between breeds and within breeds, but we generally find that most collies tend to reach adolescence at around 8-12 months old, and it can last until they are 3 years old. The start and end of adolescence in border collies varies between individuals and some may be as young as 6 months. Anecdotally, trainers and behaviourists find that high energy working breeds such as collies tend to mature physically and behaviourally later than some other breeds, meaning that border collie adolescence may be later.
It’s important to know that early neutering will not stop adolescence.

car chasing border collieHow can we recognise the start of adolescence?

  • Our collies might start to wander off and explore more instead of staying close to their caregivers.
  • They might suddenly stop coming when called and start to pull on the lead.
  • They might approach people, dogs or other subjects or items, then suddenly realise that they are scared and react.
  • They might start to become more territorial and start barking at delivery drivers.
  • They might start to react to other dogs, people, traffic or other triggers.
  • They might start to develop herding-type behaviours such as stalking, eyeing, chasing and nipping.
  • Car chasing, shadow chasing and behaviours such as guarding doorways or resource guarding owners may start to develop.

In the collie’s brain

Adolescence is less about the physical development of the collie’s body and much more related to the development of the brain. In adolescence, the collie’s brain is still evolving, but the neurons in the brain that inhibit behaviours (making strong emotional reactions less likely) are developing more slowly than the neurons that are causing the dog to feel a range of strong emotions. This causes increased likelihood of reactivity with dogs having less control over their emotions.

The amygdala, (the area of the brain that is responsible for fear responses and fear-based memories) is much more active during adolescence and these fear responses are more resistant to change. Even worse, the cortex, (the “thinking” part of the brain, that controls how we respond to stimuli) is still evolving, and there is less signalling between the cortex and the amygdala in adolescents compared to adult dogs. We therefore start to see increased risk taking, exaggerated responses and more resistant fear-based memories that are difficult to extinguish.

The HPA axis, the system that becomes active when we are fearful, is twice as active during adolescence as at other times in the dog’s life, meaning that the dog is much more sensitive to frightening events. This can lead to our teenage dogs becoming fearful of stimuli that they were previously not frightened of, and they essentially enter a second fear period during adolescence (the first is from roughly 12 to 16 weeks). This is why it’s really important to try as hard as we can to protect our collies from any unpleasant or frightening event during the first three years of their life.

These changes in the adolescent dogs’ brains cause them to be particularly susceptible to the effects of trigger stacking – where one overwhelming event after another can provoke an aggressive or fearful response when each event individually would not trigger a noticeable reaction.

Finally, the chemical that makes dogs anticipate reward (dopamine) peaks when our teenage dogs access their reward, whereas later in life dopamine is at its highest level when we are anticipating reward (which is why people often say Christmas is an anti-climax after all the excitement in the run up). Children would disagree with that, and so would our teenage collies. They want the reward NOW and are less able to cope with waiting or working for a reward.

In the body

The body is maturing more quickly that the brain, which is why we often think our adolescent dogs should “know better”. They look grown up!

It’s important to remember that adolescent children can experience growing pains, and this is something that our dogs may be experiencing as well. Pain in dogs can cause changes in behaviour, including aggression, and musculoskeletal issues, such as hip dysplasia, often start to cause the dogs problem during adolescence. Any sort of pain decreases the dog’s threshold for reaction (see our “managing arousal” blog post) and makes unwanted behaviours more likely, so it’s really important to rule out or treat pain in many cases of problem behaviours in adolescent dogs.

Hormonal changes can increase our dogs’ stress responses and growth hormone affects availability of the sugars that the brain needs to fuel it. So, with reduced availability of sugars generally during adolescence, a lot of exercise can take away the vital sugars that the brain needs. This is one reason why regular meals as well as feeding treats throughout the day is a good idea to keep our puppies’ brains fuelled so that they can keep thinking properly and not over-react to everything!

Our adolescent puppies have an increased heart rate, respiration rate, muscle tension and temperature, and due to an increased physical response to stress, teenage dogs are much more likely to develop skin problems or gastro-intestinal issues.

Neutering adolescent dogs

Research suggests that neutering can lead to an increased likelihood of behaviour problems and/or contribute to certain health issues, leading to:

  • A stress response twice as active as entire dogs
  • Increased frustration
  • Potential pain

Additionally, the anaesthetic can cause issues with the microbiome, as can the stress of the procedure, and there is growing evidence that the microbiome has a much bigger effect on behaviour than previously thought.
It’s also important to remember:

  • Not to spay bitches within the first 20 weeks after a season – this can cause a condition in which the bitch is in a permanent state of phantom pregnancy.
  • Entire males can’t help totally switching off from owners when they encounter the scent of a bitch in heat – it’s not a choice for them, it’s an overwhelming drive.
  • The teenage phase is when males may start to roam, but their sex drive can wax and wane, so may be stronger some days than others.

There are many reasons why a vet might want to neuter a dog so always bear in mind any medical conditions and be guided by your vet as well as your behaviourist.

So what do these changes in our dogs during adolescence mean for us?

Always bear in mind that in the past, when our dogs’s descendents were wild animals, adolescence was the time when dogs would need to leave the nest and safety of their immediate family and go out into the big wide world to make new friendship groups and find new partners. This is how dogs (and humans) have evolved for many hundreds of years. Therefore, their hormones and goals change during adolescence. It is only natural that they find the company of their families less interesting than the company of other dogs, people and potential sexual partners. Their hormones drive them to try new things and take risks, because they are less aware of the consequences of their actions, and their brain development, based on the wild living of their descendents, is focused on fear to make sure that they notice things that may kill them at this crucial time when they are leaving the protection of their parents and siblings.

During collie adolescence, we therefore may see:

Adolescent border collies

  • A fluctuating attention span
  • A desire for independence
  • An increased likelihood of being scared of things
  • Increased interest in novel foods, and other dogs or people
  • More risk taking (eg. rushing over to dogs)
  • An increase in frustration
  • Increased arousal
  • Much less self-control
  • More likely to switch into aggression during play

All of these changes can lead our collies to performing problem behaviours that they can’t really help – it’s down to us to help them manage their emotions and to only put them into situations in which they can cope, in order to avoid:

  • border collie suddenly resource guardingInability to concentrate on handler
  • Increased likelihood to be frightened by triggers which can lead to reactivity
  • Running off to meet new people and dogs
  • Increased barking around the home
  • An increase in herding behaviours
  • An increased dislike of being touched (due to heightened stress response)
  • Roaming behaviour (especially in males)
  • Resource guarding (guarding food, toys or chews)
  • Resource guarding in bitches after a season
  • Decreased response to cues from owners
  • Increased conflict with owners – starting to growl when being told not to do something they want to do
  • Increased conflict with other dogs, especially between young adolescent males


Teenage border collieAggression can very commonly develop during border collie adolescence, and by aggression I mean growling, snarling, barking or lunging at triggers, because of all the changes that the dog is experiencing. It’s important to manage this aggression during adolescence, in order for the dog to be able to “come out the other side” a well-balanced, non-aggressive dog.

Some dogs are naturally more prone to aggression and these are the dogs that may not improve after adolescence, even with help. There are usually signs of aggression before adolescence with these dogs.

The best tactics for dealing with aggression in adolescence include:


Not allowing the dog to practise the aggressive behaviour – if it happens once, try to prevent it from happening again. This involves management of the environment. So, for example, if your dog growls at you when you try and move him off the dining room table, put things on the table so that he can’t jump onto it (big cardboard boxes work well). If he growls when you try and retrieve a stolen sock from him, ensure that there are NEVER any stolen socks to steal and guard. If he growls at another dog in your household at dinner time, keep them separate when there is food about. There is almost always a way to manage the environment so that your dog has no need to use aggression. This might mean a bit of temporary reorganisation in your home, but it is worth it to avoid the aggression.

Avoid conflict

Always avoid conflict in adolescence. If a dog growls at you, back off and follow the advice above. This IS NOT “giving in”. It’s teaching your dog that we are listening to what they are trying to communicate. Ignoring a dog’s growl will teach your dog that growling doesn’t work, meaning that over time they may give up growling and just bite. Dogs that bite with no warning are unpredictable and dangerous.

No punishment

Punishing dogs is not only ethically wrong and unnecessary, but it causes conflict, and we need to avoid conflict with adolescent dogs at all times. Dogs that are punished during adolescence are more likely to retaliate, and we can end up setting up a pattern of conflict instead of building on our relationship with the dog. It is much better to set everything up so that your dog is always in the right, then you don’t have to punish him. You can focus on praising him instead, and your relationship with him will be so much better.

Be consistent

Not using punishment isn’t the same as being permissive. If you don’t want the dog to jump up to see what’s on the worktop, for example, insist that they don’t. Have the dog on a long line, and every time they jump up, say no and gently pull them off (with the long line – never pull an adolescent dog’s collar). Once they are off they are right (they are not jumping up) so praise them a lot for getting off. Make it more worth their while to be off the counter rather than jumping up using praise and food, which they can only access by being on the floor.

Be sympathetic

If your dog is being aggressive to strangers or other dogs, the chances are that they are scared. They are not nasty dogs – they just need our help and support. They need to be kept away from the scary trigger so that they can’t practise the behaviour (the more a dog performs a behaviour, the more they will use that behaviour in the future).
Even if their behaviour isn’t related to fear, but due to frustration or other sexual urges, they still need our help to get them through this period.

Castration of dogs

Castration of male dogs will NOT automatically stop any aggression. It will only help if the cause of the aggression is related to the dog’s sexual drive. If it’s caused by fear, then losing the testosterone could make his aggression even worse, and I’ve seen this many times, when dogs’ fear-related aggression has become much worse after castration.

Speying bitches

Sometimes hormones related to actual or phantom pregnancies can make a female dog gather resources in preparation for an actual or phantom pregnancy. In this state, food and nesting sites become increasingly valuable after a season, and she may start guarding resources from other dogs or people for up to 20 weeks after her season. In these cases, then speying her 20 weeks after her season could help – discuss it with your vet.

So what can we do to help our adolescent dogs?

border collie crate training


Adolescent dogs are still puppies. They still need a lot of sleep. Sleep allows them to recover from any frightening or over-exciting experiences and allows their arousal to decrease again. Note: if your dog has a frightening experience, try and do something else with them that is more positive before they go to sleep. Doing something they enjoy that is calming (scatter feeding, lickimats, snuffle mats, hiding treats for them to find) before they sleep will help to ensure that they are less likely to remember and be affected by the frightening experience, or at least be less affected by it.

border collie recall training


It’s tempting to try and walk our adolescent dogs more to try and “tire them out”, but this can have the opposite effect. Keeping them calm and doing lots of calming, sniffy, licky activities, will tire them out more, and keep them calm. Lots of exciting walks, while tiring them out briefly, leaves them fitter and requiring walks for further and further for the same effect. This isn’t good for their joints, and can starve their brain of the essential sugars it needs to think and make sensible decisions.
Try not to walk dogs in busy locations all the time – have some quieter, calmer walks. Focus more on “sniffy walks” than distance. Stop every time your dog wants to sniff and let them.


Growth hormones affect the availability of sugars, so in order to keep the brain supplied with sugars, feed your adolescent dogs regularly throughout the day – training them with treats is a good way of doing this.
Food intolerances may develop during adolescence so always contact your vet if your dog has excessively runny poos, is itching/scratching a lot or has problems with anal glands, all of which can be caused by food allergies.
A dog’s microbiome can be related to a range of problem behaviours for reasons that are not yet completely clear. So ensuring that your dog’s poos are regular and solid is important.

The following factors can upset your dog’s microbiome:

  • Antibiotics
  • Anaesthetics
  • Unsuitable diet
  • Parasite infection or treatment
  • Stress

The following factors help support a healthy microbiome in your dog:

  • Probiotics
  • Bone broth
  • Fresh foods and treats
  • There is a possibility that even herbivore poo could help!

training a border collie puppy to tug


Providing your adolescent collie with 3-5 activities a day is thought to be ideal (with a walk being one activity). However, try and keep activities calm. Avoid high energy games and activities within the house if you want your dog to settle more easily in the house. Independent enrichment such as the following can help:

  • Treat searches
  • Chewing
  • Kongs
  • Confidence courses (free work)
  • Searching

Border collie adolescence - social interactions

Social interactions

Our adolescent collies need our help to regulare their interactions and ensure that they don’t get themselves into difficult situations. Older dogs are much less tolerant of youngsters, and collies are so sensitive that an aggressive interaction with another dog during border collie adolescence could easily end in a lifelong fear of other dogs. It’s the same with people – don’t let your dog go running up to everyone they meet – some people won’t like this and if they react negatively, this could scare your dog.
Arrange walks or meeting with other dogs that you know are friendly and unlikely to react, and even better if they will play. Social walks can lower arousal around other dogs and improve their ability to focus on training.

Be very careful with dog daycare or dog walkers. Ensure that they are able to guarantee that the interactions your dog has with other dogs in their care is only positive. Male adolescent collies are likely to misjudge their ability to challenge other dogs and win, meaning that they may start fights more often. Ensure that your dog carer is aware of this.

Your relationship with your dog

Consistency is key – continue to insist on the behaviour that you want, even if it feels like you are fighting a losing battle. Lower criteria and ask for less than you would have done before adolescence. Remember that our adolescent collies are struggling with a range of hormonal issues.
Use high value reinforcement to reward good behaviour, and regularly vary the reinforcement – adolescent dogs appreciate novelty.

Work on the following training

  • Settle at home and out and about
  • Loose lead walking
  • Recall – practise, practise, practise!!!
  • Spend a lot of time just sitting, watching the world go by with your dog
  • Self-control exercises
  • Herding games, such as sheep balls
  • Scentwork – finding treats or itemsCooperative care – getting your dog used to being handled, groomed, having their harness put on, having teeth and ears checked.
  • Tricks

How to deal with the following common over-excitement/poor manners problem behaviours:

  • Jumping up
  • HumpingCounter surfing
  • Leash ragging
  • Lurching on the lead
  • General impatience

Stay calm and attempt to pre-empt the behaviour: make a note of when it is likely to occur and change the environment or your behaviour to stop it from occurring in the first place. Move slowly, talk softly and talk calmly. If necessary, redirect him onto something else – another activity or toy. Sometimes it’s just easier to step out of the room and take a deep breath before trying again!
Get the help of a trainer or behaviourist if the problems persist.  I’m always happy to help – contact me if needed!

4 thoughts on “Border Collie Adolescence”

  1. Fascinating article, I am looking to rescue an older dog and had been thinking about maybe 8 plus but now thinking I could end up with a dog who has not been well managed so might be better to get a younger dog (not a puppy) and train him/her myself. I had a brilliant Collie girl that I had from aged 9 and she was the best dog ever until she died at 15 but I guess that was just lucky as she had been well trained by her owner who had died.This insight into behaviour is so useful and Collie specfic.

    • Hi Claire, it’s so lovely to hear that you’re thinking of adopting a collie. There are so many in rescue right now. Best of luck and you know where I am if you need me. xx

  2. This is very good advice , my adolescent male collie , is doing well , he learns fast , he has had the added anxiety and fear after being attacked by two staffies lucky enough I was able to fight then off , they were both off their leads and mine was on his lead , but caused him a lot of trauma to the point he didn’t want to go for his walk , I coaxed him and made sure I would protect him , so now he likes his walks again , but if we see another dog he is sometimes reactive , but he is also good at remembering how we dealt with going out , he sits and waits until the other dog is out of sight , before we walk on , but he is on the look out . All in all he is developing properly, he is a joy to have around , he likes to help me with doing chores , he will bring washing down to the washing machine , he puts his toys in his box at bedtime , he help me in the garden by taking weeds etc from me and putting them into a tub to go into the bin , he is wonderful , and I’m aware he is still a youngster not 2 until January , he learns something new every day , I couldn’t imagine life without him ,
    Thankyou for your news letter today
    Sandra chapman & Bryn

    • Hi Sandra, you’re very welcome – he sounds absolutely gorgeous. Well done with your lad – it’s always so hard when they’ve been attacked. Try and pair other dogs with food, so that the other dogs become the predictor of something good rather than something bad. If he won’t take food then you might be too close, so he is too worried. In that case, move further away and try again. Good luck!


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