Approaches to aggression

While they are integrated into the everyday world of humans, dogs still have their own modes of expression. These have sometimes been used, and even exploited by humans for highly debatable ends. Consequently, we do not always identify the truly aggressive dogs and the poor reputation some breeds have is not always based on objective or proven facts.

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“How the dog experiences the world

It requires a great deal of effort to understand the dog’s “Umwelt” – a German term for the world as experienced by a particular animal – and how they see us. Wherever they are found, feral dogs most often live peacefully with other dogs and with humans provided resources are relatively abundant. The small number of scientific studies dealing with wild dogs in the forests or stray dogs in cities confirms all these observations. In the vast majority of cases, dogs that live together or with humans do so in a spirit of cooperation and harmony. But even dog lovers cannot say that they have never come across dogs that are aggressive towards humans or other dogs. In the vast majority of cases, we are responsible for this aggression.

History of Molossers

When humans first started to settle and practise agriculture and animal breeding, they also discovered that dogs were not only great companions and hunters, they were also impressive guards and efficient waste disposers. By crossing the strongest with the most ferocious and the best guard dogs, within a few thousand years in different parts of the world we created stronger, more ferocious dogs with even more acute guarding instincts. These were the first Molossers. We have not been able to produce a precise timeframe or identify exact geographical locations, but we do have a few descriptions of dogs employed in antiquity based on their ferocity and courage in battle against enemy armies. Alexander the Great and Scipio the Roman have both left epic works describing packs of war dogs that were let loose on the enemy. Dogfights in Roman amphitheatres are also mentioned. The modern Bulldog is descended from dogs which less than two hundred years ago were still used for bull-baiting in the UK, where Bulldogs were also crossed with terriers to produce a faster fighting dog, the Bull Terrier. Miniature fighting dogs bred in the central market of Paris at the beginning of the 20th century but soon banned are the ancestors of the modern French Bulldog, which themselves are pleasant little companion animals very popular with city folk.

Underground dog fighting continues to this day in many countries, often using American Pit Bull Terriers or similar types. Organisers and owners face custodial sentences and large fines if convicted.

Military dogs

The military has taken advantage of the courage and athleticism of selected breeds, originally sheepdogs, for over a century. Almost all the world’s armed forces now train dogs to save humans by putting their own lives on the line.

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Why does my dog bark when left alone at home?

This type of behaviour is called separation anxiety and it is a common problem. Dogs are social animals and they perceive isolation as a serious threat. Teach your dog that to be alone is in fact a pleasant activity. After a long walk you can give your pet a rubber toy filled with treats and don’t pay any attention to him or her. When your pet is engaged with the toy, go to another room and shut the door behind you. Then open the door shortly afterwards so that your dog doesn’t notice your absence. This game should be played as often as possible and it is recommended to change the rooms and extend the period of your dog’s isolation. Then you can try to leave your home in similar manner. If your pet can stay alone without problems for half an hour, it is usually easy for him or her to be in isolation for longer periods.


Hana Žertová,
Doctor of Veterinary Medicine
(Czech Republic)

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Why do dogs sometimes eat dirt?

Pica is defined as eating nonfood items (including faeces). It can be related to behaviour (i.e. boredom, curiosity) but is sometimes associated with a specific disease process (examples include digestive problems, liver disease, and anaemia). An especially concerning consequence of pica is the possibility of intestinal obstruction or perforation, either of which can be a life-threatening condition.


Olivier Dossin, DVM PhD DECVIM-CA University of Illinois College of Veterinary Medicine, Veterinary Clinical Medicine (USA)

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1) Causes of pica

Pica is the craving for and eating of unnatural foods such as dirt, clay etc. There is no real clear cause, but pica may be due to medical or behavioral problems and should be further evaluated by your veterinarian. It is often incorrectly assumed that pica is due to a nutritional deficiency. This is rarely the case if the pet is eating a good quality complete and balanced pet food.

2) Why don’t we change pet foods frequently?

Veterinarians do not recommend changing foods frequently because pet foods are formulated to be complete and balanced-providing everything the dog needs, in the proper “balanced” amounts. However, there can be a significant variation in nutrient levels such as fat, protein and fibre content between foods. Sudden changes in any of these nutrient levels may cause gastrointestinal upset which could cause flatulence, nausea, diarrhoea or vomiting.


Julie A. Churchill DVM, PhD, DACVN
Asst. Clinical Professor
Companion Animal Nutrition
University of Minnesota College of Veterinary Medicine
St. Paul MN (USA)

The impact of genetic selection by humans

These examples from history and prehistory, right up to the present day, all confirm that genetic selection and training by humans can be employed to produce an attack or guard dog that is potentially aggressive in certain circumstances. On the other hand, when they are left to their own devices and their reproduction is not interfered with they can live alongside humans throughout the world without resorting to aggression towards either us or other dogs. Genetic selection by humans can have a considerable positive impact on temperament when the goals are reasonable. Who would believe that those adorable little French Bulldogs are descended from formidable fighting dogs that drew big crowds in Paris just a century or so ago? Most of the molosser-type dogs found today are loyal and devoted protectors which on the inside, are nothing like their ancient ancestors.

The impact of development, environment and lifestyle

Leaving aside genetic selection, which we have seen can be used to change an aggressive temperament in a positive or a negative way, the conditions in which the puppy is raised in the first few weeks and the conditions and environment in which it spends the rest of its life have the greatest bearing on its social abilities with regards to other dogs and humans.

© Diffomedia/Royal Canin

Almost three weeks into its life the puppy is ready to encounter humans, other dogs and experience its physical environment. The encounters and experiences it has in the next few months will be decisive for its future emotional balance. If it is allowed to explore a rich and varied physical environment, full of smells, sounds, sights and other beings, it will experience thousands upon thousands of sensations which it will be able to use as points of reference in its later life. As the number of formative positive experiences and social contacts with various dogs and humans is gradually increased, the puppy will learn to respect others, to behave in a “civilised” way, just like a child at school. It will also be more sociable. Science has now confirmed something we have known in our hearts for a long time: our longstanding canine companions can be just as civilised as we can, provided they are raised in the right conditions. The aggression shown by selected individuals is almost never a matter of nature, but rather a consequence of nurture.

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My dog keeps chewing the furniture. How can I stop him?

The first idea is that you can’t or shouldn’t stop a dog chewing. This behaviour is a natural and healthy activity for puppies and dogs. Dogs will always chew, because they use it as a pastime. There are breeds more predisposed towards chewing than others, especially hunting dogs (like Retrievers, Spaniels and Hounds). Chewing is also a form of occupation therapy to relieve stress and release energy. Boredom, loneliness, frustration and anxiety are leading causes of destructive behaviour like chewing. Dogs can adopt compulsive behaviours as a response to stress. It’s necessary to consider these causes in order to properly address the issue.

Some owners allow puppies to get away with chewing but will not tolerate it from an adult dog. To avoid an adult destructive dog, the puppy needs to clearly understand as soon as possible that only toys are for chewing and then get him to stick to this rule. Particularly when the puppy is teething, it is very important to have chew toys available all times.

A great way to stop your dog from chewing furniture is to re-direct the chewing behaviour. As you find your dog chewing furniture, you should take a toy and re-direct his attention to the toy. When he turns his attention away from the furniture onto the toy, you have to praise him greatly. The same praise need to be given when you find your dog chewing the correct items. This will give positive reinforcement around chewing the correct objects. Please remember that punishment will not deter chewing but can actually increase the behaviour.

Remember that dogs have always been pack-oriented animals and their sociable nature makes them require plenty of time interacting with you. Your dog needs your companionship, mental and physical stimulation. They need sufficient exercise, because an excess of energy can cause more stress and associated destructive behaviour. If you have no time for it, you can use dog-walking or dog-sitting services. In some places you can also find doggie day-care. But your dog has a mind too! To keep your dog happy, he also needs mental stimulation. There are active toys that stimulate your dog and allow him to play alone, keeping him occupied for hours on end.

To sum up these hints to control your dog’s chewing habits, you will need to consistently follow the training methods adding a touch of patience and you will be well on your way to solving the problem.


Gonçalo da Graça Pereira, DVM, M.Sc.
Clinical Ethology and Animal Welfare
Assistant Professor,
Faculty of Veterinary Medicine
Lusófona University (Portugal)

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