Barking is a normal behaviour in dogs. Humans have encouraged and selected for barking over generations of domestication. What constitutes excessive barking can be subjective, but it can be associated with problems for owners, neighbours and the dog.
Dogs bark excessively for different reasons. The dog may be bored, lonely, scared, frustrated, or suffering from separation anxiety [1, 2].
Excessive barking as an indicator
Excessive barking is usually an indicator of underlying issue(s) such as pain, fear or distress, the presence of trigger(s) (e.g., passers-by, other dogs barking) and/or failure to meet the dogs’ mental and physical needs (e.g., insufficient exercise, mental stimulation and/or social interaction).
Boredom, loneliness and frustration
Excessive barking in dogs who are left alone all day with nothing to do may be an expression of boredom, loneliness and frustration. They may bark continuously and may also perform behaviours such as digging up the garden.
Excessive barking may be a dog’s way of expressing fear, and/or warning of a real or perceived threat(s). They may be fearful of people or dogs approaching and certain noises (e.g., fireworks, thunderstorms, lawnmowers).
It is natural for a dog to want to warn others about real or perceived threats. Your dog may bark excessively at visitors and people strolling past because they are perceived as potential intruders.
Continuous barking is just one of the potential symptoms of separation anxiety (severe distress when left alone), which may also include destructive behaviour, inappropriate urination and defaecation, and self-harm (e.g., chewing or licking themselves until they create wounds). Dogs with separation anxiety are not coping with being alone. Separation anxiety is a mental health issue that requires veterinary treatment.
Identifying the reasons for excessive barking
Identifying the reason(s) for excessive barking requires characterisation of the dog’s environment, daily activities, and barking habits. Keeping a diary can help identify the triggers and/or unmet needs :
- When and where does the dog bark excessively?
- Is the behaviour associated with particular sights or sounds?
- Does it occur when their owner(s) are at home or away?
- Is the dog left alone for long periods with nothing to do?
- Does the dog have the opportunity to engage in daily exercise, natural behaviours, and physically and mentally stimulating activities?
If excessive barking persists, seek the advice of a reward-based dog trainer, veterinarian, and/or qualified veterinary behavioural specialist, especially if the dog is suffering from separation anxiety. See the Knowledgebase article ‘My dog is barking excessively, what should I do?’ for more information.
 Pongrácz P, Molnár C, Miklósi Á (2010) Barking in family dogs: An ethological approach. The Veterinary Journal 183:141–147
 Cross NJ, Rosenthal K, Phillips CJC (2009) Risk factors for nuisance barking in dogs. Aust Vet J 87:402–408
 Righetti J (2004) Barking up the wrong tree: The importance of understanding and correct diagnosis of barking in dogs. In: Urban Animal Management Conference Proceedings. pp 13–14