Aggression in dogs - motivation and causes


At the heart of every dog ​​owner lies the desire to develop a harmonious relationship and a deeper understanding with their four-legged friend. But what happens if the loving companion suddenly shows aggressive behavior? Aggression in dogs can have a variety of causes and manifestations, and the reasons behind it are often misunderstood or unknown. The nature of these behavior patterns is rooted in both the dog's biology and its environment and upbringing. In a world where quick conclusions and stereotypical assumptions prevail, this blog invites you to explore the complex networks of cause and effect that underlie aggressive behavior in dogs. We delve into a multidimensional view, ranging from genetic factors to physical and mental health to different motivations for aggression in dogs.

Definition of aggression in dogs

The word “aggression” is often used when we talk about challenging or difficult behaviors in dogs. But what exactly is “aggression”? This is where it gets tricky, because there isn't really a uniform definition that covers all facets. 

Aggression often serves the purpose of creating a perceived avert threat or to defend resources.

Dr. Dorit Urd Feddersen-Petersen, an expert in the field of dog psychology, explains it this way: “Aggression comes from the Latin word «I attack», that as much as «approach" or «approach something" means. In animals, especially canids (i.e. dogs and their relatives), this is often the case securing space and asserting or defending one's status in a group. Expressed in a simple way: «Here I come, make room!», the dog might say. Aggression is also a way in which dogs communicate with each other and with us - and this communication is often more complex than it appears at first glance (Feddersen-Petersen, D. (2014). Dog psychology: social behavior and nature - emotions and individuality. Kosmos).


The definition of aggression thus expands far beyond the simple concept of a physical attack and broadens our perspective on the role that this behavior plays in the social dynamics and survival of animal species, particularly canids such as dogs. Aggression should not only be understood as potentially harmful behavior, but also as a complex and essential means of communication within social structures. Aggression in dogs is therefore normal behavior and is an essential part of communication (Heberer, U., Brede, N. & Mrozinski, N. (2017). Aggression behavior in dogs. Kosmos).

Intraspezifische Aggression

“Intra-” means “within” or “self”, thus “Intra-specific aggression” refers to aggressive behavior within a species. In dogs, this would be aggressive behavior from one dog towards another dog. This can manifest itself in various forms, such as conflicts over resources (such as food, toys or sleeping places), in response to perceived threats, or in contexts of social hierarchy and dominance behavior. Intraspecific aggression can occur due to competition, mating disputes, territoriality, or social hierarchy dynamics.


Example: Two dogs fighting over a toy and exhibiting aggressive behavior such as growling, showing teeth, or biting.

Interspecific aggression

“Inter-” means “between”, so “interspecific aggression” refers to aggressive behavior between individuals of different species. For example, in a dog this may include aggression towards people, cats, birds or other animals. This type of aggression can be triggered by prey drive, fear, protection of territory or resources, or a number of other factors. So interspecific aggression is what we often see when dogs react to other animal species in a way that can be interpreted as aggressive.


Example: A dog chasing or barking at a cat would be an example of interspecific aggression.


Aggressive behavior as communication: Understanding instead of condemning

Understanding aggressive behavior in dogs means taking a look at how they communicate. Dogs do not have the complex language of humans and instead communicate in other ways to express their needs, fears, joys and discomfort. Aggressive behavior plays an important role here, which is often misunderstood. Aggression is not the same as dangerousness. It is essential to emphasize that aggressive behavior does not necessarily mean dangerousness. When a dog growls or even shows his teeth, he is not always expressing a direct threat, but is signaling that he is demanding more distance. We as dog owners need to be aware of the escalation levels of aggressive behavior. If I punish my dog ​​for growling or showing his teeth, this can in the long term lead to the warning signals disappearing in the future and my dog ​​snapping straight away. It is therefore essential to distinguish between the different forms and causes of aggression in dogs in order to react adequately to them and avoid potential conflicts.

Different motivations for aggressive behavior

Wouldn't it be great if there was a simple list that told us exactly why a dog is aggressive and what we can do about it? A checklist like this would be super practical, but unfortunately it's not feasible. This is because dog aggressive behavior is complicated and influenced by many different things. So it is not easy to determine an exact reason for the behavior and find a clear solution. Behavior in dogs is fundamentally multifactorial. This means that behavior can occur not only for one reason, but for many different reasons. If a dog shows aggressive behavior, there is rarely just one motivation behind it. There are often several reasons that encourage the dog to behave aggressively and the dog can switch between the drives within a sequence. It is simply impossible for us humans to filter out just one motivation. Nevertheless, we would like to explain to you some motivations for aggressive behavior. 

Mixed motivation

In most cases, aggressive behavior arises from a mixed motivation in which different forms of aggression play a role at the same time. This means that the dog does not react aggressively for a single reason, but rather his reaction is a mixture of various internal and external drives. For example, a dog could react territorially and at the same time aggressively out of fear. The presence of multiple motivating factors makes it difficult to identify the exact trigger for the aggressive behavior and intervene accordingly. Mixed motivation can also cause a dog to send inconsistent or difficult-to-interpret signals, making it challenging for the owner to correctly read their animal's condition.

Threatening behavior

Anxiety aggression

Fear aggression in dogs refers to aggressive behavior that arises from fear or insecurity. A dog that reacts aggressively out of fear is often trying to ward off or avoid a threat, whether real or imagined. This behavior is a form of self-protection to protect yourself from something that is interpreted as dangerous or disturbing. Fear is an emotion that occurs in response to a perceived threat or danger. It serves an important function in survival and protection by causing living beings to respond to potentially dangerous situations in a way that minimizes risk. However, in dogs (and animals in general), fear can be triggered not only by situations that are actually threatening, but also by circumstances that they interpret as such - even if there is no real danger.

The concepts of “Flight, Freeze, Fiddle, Fight” are often central to understanding fear responses in animals, including dogs. These four "F's" represent different ways animals can respond to fear or a threat:

1. Flight

The flight response is a common response to fear or danger. When a dog perceives a situation or object as a threat, its first reaction may be to try to move away from that threat. He could run away, hide, or go to a safe place. This type of behavior is intended to get the individual out of possible danger. Unfortunately, in an everyday situation when walking, this is not always possible for the dog because the leash could prevent him from hiding. 

2. Freeze

In a fearful situation, a “freeze” reaction often occurs. This is a survival mechanism that occurs in dangerous situations to avoid being noticed by predators. If the dog cannot escape from a frightening situation, he usually freezes. This can serve as a type of defense mechanism, especially when escape is not possible. The dog remains completely motionless and waits, often hoping that the threat will go away on its own or that it will not be noticed.

3. Fiddle (fiddles/distraction)

“Fiddle” or as Fidget refers to a type of distraction behavior or self-soothing. An unsettled dog may begin to exhibit behaviors that are considered... appeasement signals could interpret. The goal is often to reduce one's own tension and at the same time send non-verbal signals to the perceived threat that say: "I am not a threat to you." In this context, some dogs begin to show playful, rather silly behavior Dog owners then interpret this as a friendly invitation to play. This incorrect assessment can be really dangerous. 

4. Fight (Kampf)

If escape, freezing, or distraction are not possible or unsuccessful, the dog may resort to fighting as a last resort. This means that he shows aggressive behavior to drive away the threat, true to the motto “attack is the best defense”. “Fight” is often a last line of defense when the dog feels he has no other way to defend himself. For example, dogs that do not receive enough protection from their humans because the human misunderstands “Fiddel,” or the dog is left alone in its fear, will show aggression more often in the future. The original fear aggression then becomes learned aggression because the dog knows from experience that he has been successful with the aggression strategy so far. 

It is important to understand these reactions as normal behaviors that, from the dog's perspective, serve to protect itself from possible threats. A deeper understanding of these reactions and their triggers can help create environments and situations that minimize stress for the dog and help him feel safer and more relaxed. Proactively dealing with anxiety and stress in dogs, possibly with support from a professional dog trainer or animal behavior specialist, can be crucial to the animal's well-being.

How to recognize fear aggression: 

✔️ Dog is incapacitated

✔️ refuses treats 


Learned aggression

Learned aggression can be taught to the dog unconsciously or consciously. In the case of unconsciously learned aggression, the dog has learned based on his experiences that his dog is either unable to protect him adequately, in that the fear and fiddling shown were misinterpreted and interpreted as a request to play, or unintentional learning processes of aggressive reactions to certain places or environmental stimuli.

Consciously learned aggression, for example, is part of protection dog training. Here, dogs are conditioned to certain stimuli or processes in order to show aggressive behavior in specific situations. When it comes to dog sports of this type, it is important to have appropriate training tailored to the dog so that uncontrollable behavior does not develop.

Schutzhundausbildung, Hund beisst in Beissarm
Schutzhund training

Resource-related aggression

Resource-related aggression, often referred to as resource defense, is a form of aggressive behavior that occurs when a dog attempts to defend or secure a valuable resource.

  1. Food and treats: This is one of the most common resources that dogs defend. A dog may growl or snap if someone approaches his food bowl while he is eating.
  2. Toy: Some dogs exhibit aggressive behavior when they have a beloved toy and someone tries to take it away.
  3. Berths: A dog may view a favorite blanket, bed, or specific spot on the couch as his resource and defend it.
  4. People: A dog may view a particular person (often the primary owner) as its resource and react aggressively if it believes that person is threatened by others.
  5. Territory: Although this can also fall into the category of territorial aggression, places like the backyard or the house can be viewed as resources to be defended.

Resource-related aggression in dogs is manifested by a notable fixation and defense of objects such as food, toys or sleeping places, where the dog usually has an immediate presence and direct defense of the desired object. When another individual, be it human or animal, approaches, the dog stiffens, fixes the object with his gaze or stares just past it and begins to threaten clearly by growling, baring his teeth and widening his eyes. Depending on the dog's motivation, his aggressive behavior can appear both offensive and defensive. It is also important to emphasize that the intensity with which a dog defends a resource is influenced by various aspects. This includes the value of the resource itself, the opponent against whom the resource is being defended, and the status of the defending dog - including character, breed characteristics, gender, health status and age. Dogs with a higher social status tend to defend a resource more calmly and quietly or less violently than dogs with a lower social status, which tend to react faster, louder and more violently because in their position they may have more to lose and gain have to win.

Sexually motivated aggression

Sexually motivated aggression in dogs is closely linked to hormones and their behavioral effects aimed at optimizing their own reproductive chances. In male dogs, sexually motivated aggression is mainly manifested through showy behavior or comment fights, both of which aim to find agreement between male dogs without serious physical confrontation. It is rare for male dogs to become serious. The main difference is the task of female dogs and male dogs. Female dogs are responsible for raising puppies, which is why they tend to be more introspective when it comes to social behavior with people. However, in contrast to male dogs, if there are disagreements with other female dogs, the situation can be much more dangerous and even go to the point of blood. The behavior of female dogs with other dogs can depend heavily on the upbringing or character, but also on the respective cycle phase in which she is. Some dogs show aggressive behavior before, during or after heat - often in conjunction with a false pregnancy - which can lead to conflicts in a household with several dogs.

Socially motivated aggression

Socially motivated aggression in dogs arises and manifests itself in social contexts, particularly in relation to their human social partners. Sometimes socially motivated aggression can also arise when the dog wants to protect other dogs in its social group. A dog's aggressive behavior is often unintentionally encouraged by the owner's reactions and behavior - whether through fear, insecurity or even positive reinforcement. The problem of socially motivated aggression is further exacerbated by misinterpretations by the dog owner and the environment. Aggressive behavior is often misinterpreted as a protective instinct or a sign of fear, and the owner's responses - such as reassurance, petting or laughter - can further reinforce this undesirable behavior. This leads to the dog viewing its aggressive behavior as a shared experience with its human. 

How to recognize socially motivated aggression: 

✔︎  Sometimes misinterpreted as “protective instinct.”

✔︎  Can occur towards both people and other dogs.

✔︎  Can occur in different contexts (e.g. in the family, while going for a walk).

✔︎ A possible experiment for identification: The dog is tied up and shows aggressive behavior towards a stimulus. If the owner moves away, check to see if the dog shifts his attention from the stimulus to the owner. If the aggressive reaction subsides as soon as the owner moves away, it is socially motivated aggressive behavior. 

✔︎  In interaction with other dogs: Aggressive behavior may appear suddenly when introducing a new dog and could be mistakenly interpreted as territorial aggression.

Status motivated aggression

Status-related aggression in dogs refers to the hierarchy and dynamics within their social groups or associations. Hierarchies in such associations, which are based on health, age-related experience and mental strength, make biological sense and serve as orientation for all members of the group. Since the characteristics that determine an animal's rank are changeable and not static, lower-ranking animals in particular repeatedly try to improve their status through aggressive behavior, which may give them additional freedom and improved living conditions. Hierarchical structures are essential in social associations, as clear and quick decisions can be necessary for survival, for example in threatening situations. When it comes to resource management, mentally strong dogs who have a higher rank in their association tend to be more generous and more likely to release resources. The type of aggression – whether resource-related or status-related – plays a role in whether a resource is defended or a conflict is triggered. While resource-related aggression focuses on the desire not to give up a resource, status-related aggression tends to question the other party's right to withdraw a resource, which can be dangerous in certain contexts.

How to recognize status motivated aggression: 

✔︎ Offensive behavior: Expressions such as head raised, direct eye contact, and tail carried high.

✔︎ Resource and status conflicts: Disputes over resources such as food or space are often linked to questions of status.

✔︎ Subtle control: Inconspicuous methods to influence the holder's freedom of movement (e.g. blocking the path).

✔︎ Spatial monitoring: Positioning in strategic locations to control space and movements.

Territorial Aggression

Territorial behavior is a natural behavior in dogs and occurs particularly in the context of their living space. For sedentary animals like dogs, living space is a resource essential for survival. Important resources such as food or resting places are located in their territory. They raise their young in their territory and mate there. Our dogs live closely with us these days and their adaptability has affected their interpretation of “territory.” A dog not only perceives his home as territory, but can show territorial aggression on the car or on his walk. Strictly speaking, territorial aggression is linked to resource-related aggression because (living) space is a resource for dogs. Dogs have always served as valuable partners for humans when it comes to monitoring locations. Many dog ​​breeds were originally - and still are - used as farm dogs to protect the home from intruders or, in the case of livestock guard dogs, to defend the herd from robbers and predators. The Hovawart, for example, takes its name from its former role as a “court guard”. Territorial behavior develops quite late in a dog's behavioral development. It's possible that your dog won't show any signs to visitors for the first two years and this behavior will become more prominent as he ages.


How to recognize territorially motivated aggression: 

✔︎ Aggressive barking along territory (e.g. garden fence)

✔︎ Rapid approach to the border, often to a certain point

✔︎ Excitement at the territorial borders

✔︎ Blocking the path by stopping threateningly

✔︎ Running after intruders with possible attempts to attack (bite attempts)

✔︎ Carrying out mock attacks or real attacks

✔︎ Intruders are caught and barked at until they stop moving

Hund bellt am Zaun
Dog barks at the fence

Redirected aggression

Redirected aggression occurs when a dog displays aggressive behavior toward a person or animal even though their aggression was actually directed at someone or something else. This type of aggression can occur when a dog is aroused or frustrated by a particular situation or individual, but is unable to direct his aggression directly at the triggering target. A very banal example is biting the leash as soon as the dog doesn't reach its intended destination. The aggression is often directed against the dog owner, for example if the other dog cannot be addressed directly. Instead, the aggression is redirected to a closer, more easily accessible target. Whether redirected aggression is intentional or reflexive remains a point of debate. What is certain is that such aggressive behaviors can often be reduced or modified when dog training is specifically aimed at improving impulse control and managing status-related conflicts.

Causes of aggression

Aggression in dogs can be triggered by a variety of factors. Both the system and the environment play a crucial role here. The factors that can produce these behaviors are diverse and often complexly intertwined. This inevitably brings up the investment-environment debate, which deals with the influence of genetics (disposition) and environment (upbringing, socialization) on behavior. A dog may have a genetic predisposition to certain behaviors, such as aggression. Nevertheless, the environment in which he grows up and lives plays a decisive role in whether and how these abilities come into play. The genetic component determines possible behaviors, while environmental conditions significantly influence which of these behaviors are actually expressed.


Genetic factors are central in shaping a dog's temperament and behavioral tendencies. It is an undeniable fact that the DNA that a dog inherits from its parents forms the basis for many of its later behavioral patterns, including susceptibility to aggression. This does not mean that a dog's behavior is completely determined by its genes, but it does establish certain basic traits and potential that can emerge under certain circumstances. It is essential to emphasize that despite breed-specific tendencies, a significant portion of behavioral expression varies from dog to dog, and environment, training, socialization and individual experiences have a significant impact on how genetic tendencies ultimately manifest themselves. A dog of a breed with a reputation for gentleness may well exhibit aggressive behavior, and conversely, a dog of a breed often viewed as “difficult” may well be very friendly and gentle.

  • German Shepherds: They were originally bred to work with sheep and should be able to protect the flock. In some cases, this can lead to them having a certain protective and vigilant tendency, which can also manifest itself as aggression towards strangers.
  • Terrier-Rassen (z.B. Jack Russell Terrier): Many terriers were bred to hunt small game and often have high energy and stamina. They may also have a high threshold and a tendency to behave impulsively and reactively, which may result in a greater propensity for aggression, especially in situations that are perceived as threatening or challenging.
  • Bullartige Terrier (z.B. American Staffordshire Terrier): These breeds are often associated with a certain stubbornness and aggressive behavior, but this should always be viewed with caution and on an individual basis. Historically, bull-like terriers were bred for various “sports” and tasks that could encourage aggressive behaviors. In the past, they were used, among other things, for bull and bear fights, but also as rat catchers. These activities promoted traits such as bravery, endurance and a certain willingness to be aggressive towards other animals.
  • Rottweiler: A Rottweiler may have a natural inclination to protect its territory or family, due to its history as a working dog in various protective and guarding roles. Therefore, they could exhibit aggressive tendencies in certain contexts, particularly when they perceive a threat to their territory or people.

Education and socialization

When we talk about training and socialization in dogs, we are referring to the process by which dogs learn how to behave appropriately in different situations and towards different creatures. This affects their interactions with people, other animals and their environment in general.


Early socialization

Socialization begins in puppyhood and continues throughout the dog's life. However, the primary socialization phase takes place between the third and twelfth week of life. During this period, it is essential that puppies are exposed to a variety of people, animals, environments and experiences. This helps prevent or at least minimize fear of unfamiliar objects, creatures or situations later in life.


Socialization and behavior

A lack of socialization can lead to insecure or fearful behavior, which in turn can lead to aggression if the dog feels threatened or is backed into a corner. Likewise, a bad experience with a particular stimulus (such as another dog, person, or situation) during the critical socialization period can lead to anxiety and possibly aggressive behavior later in life.


The role of the owner

This is where the role of the dog owner comes into play. Adhering to a structured training and socialization plan as well as observing and responding appropriately to the dog's behavior are essential. At the same time, building a strong bond between owner and dog through trust and respect is essential to creating a safe and stable environment in which the dog can learn.


Epigenetics represents an interface between genetic factors and the environment. Epigenetics deals with changes in gene expression, i.e. how genes are “read” or “muted” without changing the DNA sequence itself. These changes can be triggered by environmental factors such as stress, diet or exposure to toxins, and can also be inherited without the DNA sequence itself changing between generations. When it comes to aggression in dogs, epigenetic factors may contribute to how and when aggressive behaviors occur. For example, trauma or severe stress to the mother dog could set epigenetic marks that activate or deactivate certain genes associated with stress responses or fear behavior. This, in turn, could influence the dog's threshold for exhibiting aggressive behavior in certain situations. It is therefore conceivable that not only the immediate learning experience (i.e. the association of conspecifics with negative experiences), but also long-term changes in gene expression contribute to the dog having a lower tolerance threshold for social stress in adulthood and being more prone to aggressive behavior .

Here, epigenetics plays a role as an intermediary between the genetic makeup of an individual and its environment by allowing life history and environmental influences to influence the function of its genes.

Physical health problems

One aspect that can greatly influence a dog's aggressive behavior is physical health problems. Pain, discomfort and a general inability to act normally can permanently change a dog's character and temperament.

Some breeds are genetically predisposed to certain health conditions that can cause pain or discomfort. For example, some large breeds are prone to hip dysplasia, while smaller breeds may be more likely to suffer from patellar dislocations. Pain from these conditions can directly affect a dog's behavior and make him irritable or aggressive, especially when his painful areas are touched.

Mental health and stress

Stress, be it acute or chronic, can significantly affect a dog's behavior. A dog that is constantly under stress, whether from an unstable home environment, regular confrontations with trigger factors, or other stress-promoting circumstances, may exhibit increased levels of aggression. You can find out more about the topic of stress here

In addition to stress, fear can promote aggressive behavior. Fear-motivated aggression has already been explained above. 

General Aggression Model


The General Aggression Model was developed by Craig Anderson and Brad J. Bushman as a framework for explaining aggressive behavior in general, often in the context of human aggression. The model aims to explain various factors that contribute to the emergence of aggressive behavior and how these factors interact in different contexts.

The General Aggression Model can be divided into three main components:

  • Input phases: These involve personal and situational factors. be environmental influences.

  • Routes or paths (Routes): This part refers to the internal mental processes. This includes thoughts, feelings and physical reactions.

  • Output: This refers to the final behavior, which can be either aggressive or non-aggressive.

If we were to apply the model to aggressive behavior in dogs:

  • Input phases: Personal factors could include race, age, health status, previous experiences or training methods. Situational factors could include immediate stimuli such as loud noises, other animals or people.

  • Routes: How the dog processes these stimuli based on his internal states, his experiences and his upbringing. What does the situation trigger in the dog and which emotions or affects does it promote?

  • output: The dog's actual behavior, which can be either aggressive, passive, or anything in between.

Although the General Aggression Model was not developed specifically for dogs, it can certainly be adapted and used as a framework to understand how various factors might influence dogs' aggressive behavior.

Vitomalia's conclusion

Aggression in dogs often raises questions and concerns among owners and the public. But behind the complex behavioral pattern of aggression there are various causes and motivations that are influenced both at the genetic level and by environmental factors. Aggressive behavior can be driven by various motivations. These range from fear to territorial defensiveness to resource defense or even hierarchy-related reactions. The key to understanding often lies in closely observing the context. 

Some breeds may be more prone to certain forms of aggression than others due to their breeding history, although individual differences also need to be considered. Although genetic factors influence a dog's potential for certain behaviors, including aggression, they are not the sole determining element. The expression of this genetic potential is always modulated by a variety of influences, including environmental factors, individual experiences and epigenetic changes. Therefore, an integrative approach that considers both genetic and environmental factors is essential to truly understand and positively influence a dog's behavior. A lack of proper socialization and training can promote aggressive behavior, even if the dog does not have a genetic predisposition to it. In addition, both physical and mental health problems can cause or increase aggressive behavior. This illustrates how complex aggressive behavior and the associated causes and motivations are in dogs. 


What is meant by aggressive behavior in dogs?

Aggressive behavior in dogs refers to any form of behavior intended to harm or threaten another person, animal, or object. This can be expressed through growling, biting, barking, or other gestures.

What are the main causes of aggression in dogs?

The main causes may include genetic factors, parenting and socialization problems, physical health problems and mental health/stress. External factors such as the environment in which the dog lives can also play a role.

Are there certain breeds that are prone to aggressive behavior?

While some studies indicate a higher incidence of certain behaviors in some breeds, it is crucial to emphasize that it is not breed but a variety of factors, including training and environment, that determine a dog's behavior. Due to the original breeding goals for hunting dogs, guard dogs or livestock guard dogs, a tendency towards aggressive behavior can be observed in different situations.

How do genetic factors influence a dog's aggressive behavior?

Genetic factors can influence the likelihood of certain behaviors by shaping the dog's physical and psychological foundation. These genetic predispositions interact with environmental factors to shape ultimate behavior.

How can physical and mental health problems affect aggression in dogs?

A dog in pain or other physical discomfort may exhibit aggressive behavior to protect itself. Psychological stress, such as chronic stress or anxiety disorders, can also lead to increased irritability and aggression.

What does correlation and causality mean in the context of aggressive behavior in dogs?

Correlation means that two things are related to each other and the strength of the relationship can vary. For example, certain types of dogs may exhibit aggressive behavior more frequently, but may not necessarily be causally linked. Aggression and race are related to each other, but are not the origin alone. Causality means that a cause (e.g. an illness) produces an effect (e.g. aggression). In dogs, it is often a combination of several factors that lead to aggressive behavior.

Are there preventive measures to prevent aggressive behavior in dogs?

Yes, this includes good socialization at a young age, consistent, fair training, regular veterinary checks and a stable, safe environment. A solid understanding of canine communication and the dog's needs are also crucial.