Dogs communicate with each other in many ways. Like us, they use posture, facial expressions and vocal tones to signal how they feel. They are also very reliant on scent to identify those around them. But it is often the nuances of their posture and actions that we as humans struggle to appreciate. Many dog owners will have experienced an unpleasant dog interaction when either their own dog or another dog growls whilst out on a walk. Understanding why a dog may behave this way can help to appreciate the feelings your dog is trying to express.

Understanding Behavioural Drivers

Your dog’s behaviour is either innate or learned. Innate behavioural responses are instinctual or genetic, and include sexual and predatory behaviours. Some behaviours that are characteristic for a breed such as a Border Collie’s drive to herd have a genetic involvement. But many of the behaviours involved in dog-to-dog interactions are learned. A dog will learn both positive and negative behavioural responses based on how it perceives, and is perceived by, other dogs.

If a dog fails to learn cues or misses out on dog-to-dog interactions during crucial developmental stages, they may struggle to interact appropriately later on. In some individuals, natural or surgical alterations to anatomy such as the ears or tail may result in the wrong signal being perceived by another dog. This can lead to confusing or apparently mixed messages. Unpleasant prior experiences may also contribute to a seemingly excessive response to a new situation.

Understanding Dog Communication

For a dog, scent is their strongest sense. They use pheromones to identify individuals, decide if they are friend or foe, fertile or not, and what sex they are. Dogs secrete these from special glands associated with their anus, genitals, and muzzle. This is the reason you will see your dog greet another with a muzzle sniff followed by a genital sniff. As this involves getting very close and personal, each dog is already giving the other signals ahead of time through posture and vocalisations, letting the other know whether it is okay to get that close.

Interpreting your dog’s signals involves looking at their actions collectively. You may have seen your dog bounce on the spot or bow down next to another dog. These are excited postures that invite play and interaction. Engaged ears, open mouths and elevated or mobile tails usually go with these. Circling behaviour and a good sniff will usually result in a shared playtime.

As with people though, not all dogs like to be approached by strangers. Some can be overwhelmed by seemingly overzealous behaviour in another dog. Others prefer only to interact off the lead, so they have the choice of retreat. If a dog is uncomfortable with the situation or lacks confidence, they will exhibit either obviously negative signals, or signs that we would class as more subtle.

A direct and face-on approach can be confrontational, especially if accompanied by lip curling, barking, or growling. But the often-overlooked signs of anxiety or discomfort may involve a tense posture with dropped ears, a side-step which may include a raised paw, or merely an eye position known as ‘whale eye’. This is where a sideways glance is not accompanied by a head turn creating a white crescent around one edge of the eye.

Understanding Growling

Growling occurs when your dog is aroused or stimulated and will follow on from, or accompany, those non-vocal cues. It can be a normal part of play, so other play behaviours need to be looked for to give context.

Non-playful growling can be either offensive or defensive and arises based on how a dog perceives a situation. This could involve a memory from a prior experience; the feeling of being sore or unwell; a response to the signals being given by the other dog; or a lack of response to their initial non-vocal cues. An invasion of space, especially when on a lead with no ability to retreat is another trigger.

These causes are often thought of as fear or anxiety-driven aggression; but they are more about emotional expression and a desire to avoid escalating conflict. These defensive growls are designed to incite the withdrawal of the other individual and prevent physical contact. 

Dogs also growl as a territorial or possessive response if they think an object or person of value is being threatened. This could include their home and garden, or you as their owner. You might see this at the park or at home with toys and food or if friends or family visit with their dogs.

In many scenarios, defensive growling will come first 

The aim is to retain space and will usually be accompanied by the other signs of an uncomfortable dog. Offensive growling is more likely to be accompanied by an erect and tense posture and bared teeth, with or without lunging. It appears assertive and is often the escalation of defensive growling where the situation has not yet been diffused.

If a stand-off becomes prolonged, a dog may alternate between defensive and offensive behaviour, including rolling over while growling in an effort to appease the other dog. If they have a history of perceived negative interactions, an individual may go straight to a heightened and more offensive growling behaviour without the initial defensive strategy. This is sometimes referred to as a reactive dog or a dog-aggressive dog and can be frightening to experience as a dog owner.

How can I help my dog?

Although we think of growling as undesirable, it is your dog’s way of coping with the current situation. Therefore, it is important to never punish a dog for reacting this way. Ideally, the behaviour should be addressed early on with both a physical health assessment and behavioural support.

Changes in behaviour could indicate an underlying health problem. Pain, such as osteoarthritis in older dogs, and internal conditions such as diabetes can impact your dog’s temperament. And it may make them seem more aversive to another dog’s attentions. Your vet can help to either diagnose or rule out a physical condition which may be affecting their mental fitness. Once a physical condition is ruled out or under management, your vet can refer your pet to a certified animal behaviourist.

A clinical animal behaviourist can not only help with getting to the bottom of what is driving the growling but can also support you in a management plan. This will vary depending on the cause and type of growling but will be individualised to your dog’s specific needs. Behaviour-modifying medication may be recommended but are not a stand-alone treatment. They are designed to assist the behavioural management plan and are not appropriate in all cases.

Behavioural therapy can sometimes take time to see outward results. And sadly, some neurological causes of growling or aggression cannot be treated. If there are concerns with your dog’s wellbeing or the safety of others, both your vet and behaviourist can discuss the implications of these and assist with decision making.


The causes of growling are varied and individual and require observation of the other cues that your dog is giving to interpret the likely cause. In some cases, the underlying trigger may have occurred prior to you obtaining your pet and may be out of your control. Seeking physical and mental health support from your veterinary team can help you achieve the best welfare outcome for your dog in the long run.

Further Reading: